We just had a severe earthquake in south eastern Turkey, northwestern Syria. We call this the Kahramanmaraş Earthquake
https://earthquake.usgs.gov/earthquakes/eventpage/us6000jllz/executive
Well, I learned tonight (14 Feb) that these M 7.8 and M 7.5 earthquakes have been named by the Turkey Minister of the Interior. The names are the Pazarcik (M7.7) and Elbistan (M7.5) earthquakes.
For AFAD, it is M7.7 Pazarcik and M7.5 Elbistan earthquakes. Both are towns of Kahramanmaras. Kandilli's naming is more complicated: https://t.co/4cTMPQyYMI
— Dr. Ezgi Karasozen (@ezgikarasozen) February 14, 2023
This earthquake is the largest magnitude event in Turkey since 1939 and it looks like there will be many many casualties.
Hopefully international aid can rapidly travel there to assist in rescue and recovery. The videos I have seen so far are terrifying.
This is the same magnitude as the 1906 San Francisco earthquake.
There has already been an aftershock with a magnitude M 6.7. This size of an earthquake would be damaging on its own, let alone as it is an aftershock.
I will be updating this page over the next few days.
UPDATE 6 Feb ’23
The East Anatolia fault is a left-lateral strike-slip fault system composed of many faults and is subdivided into different branches and different segments.
The first thing to remember is that people created these names and organized these faults using these names. The faults don’t know this and don’t care. It is possible that the people that organized these faults did not fully understand the reason these faults are here, so they may have organized them incorrectly. It may be centuries to millenia before we really know the real answer to why faults are where they are and how they relate to each other.
The Arabia plate moves north towards the Eurasia plate, forming the Alpide belt (perhaps the longest convergent plate boundary on Earth, extending from Australia/Indonesia in the east to offshore Portugal in the west. This convergence helps form the European Alps and the Asian Himalaya. In the aftershock poster below, we see the Bitlis-Zagros fold and thrust belt, also part of this convergence.
Turkey is escaping this convergence westwards. This escape has developed the right-lateral strike-slip North Anatolia fault system along the northern boundary of Turkey and the left-lateral East Anatolia fault system in southern Turkey.
During the 20th century, there was a series of large, deadly, and damaging earthquakes along the North Anatolia fault (NAF), culminating (for now) with the 1999 M7.6 Izmit Earthquake. The remaining segment of the NAF that has yet to rupture in this series is the section of the NAF that extends near Istanbul and into the Marmara Sea.
The East Anatolia fault (EAF) has a long history of large earthquakes and I include maps that show this history in the posters and in the report below (I have more to add later this week).
Today, I woke up to learn that there was a magnitude M 7.5 earthquake that happened since I posted this report the night before. This was not an aftershock but a newly triggered earthquake on a different fault than that that slipped during the M 7.8. However, there will be some people who will call this an aftershock.
https://earthquake.usgs.gov/earthquakes/eventpage/us6000jlqa/executive
The aftershocks have been filling in to reveal what faults are involved and there are many faults involved in this sequence. I include a larger scale view of these faults in the updated aftershock interpretive poster below. >>>
This M 7.5 earthquake is on a different fault than the main part of the sequence (the Çardak fault). The main sequence appears to be on two segments of the main branch of the East Anatolia fault
Below is my interpretive poster for this earthquake
- I plot the seismicity from the past month, with diameter representing magnitude (see legend). I include earthquake epicenters from 1922-2022 with magnitudes M ≥ 3.0 in one version.
- I plot the USGS fault plane solutions (moment tensors in blue and focal mechanisms in orange), possibly in addition to some relevant historic earthquakes.
- A review of the basic base map variations and data that I use for the interpretive posters can be found on the Earthquake Reports page. I have improved these posters over time and some of this background information applies to the older posters.
- Some basic fundamentals of earthquake geology and plate tectonics can be found on the Earthquake Plate Tectonic Fundamentals page.
- In the upper right corner is a map from Armijo et al. (1999) that shows the plate boundary faults and tectonic plates in the region. This M 6.7 earthquake, denoted by the blue star, is along the East Anatolia fault, a left-lateral strike-slip plate boundary fault.
- In the upper left corner is a comparison of the shaking intensity modeled by the USGS and the shaking intensity based on peoples’ “boots on the ground” observations. People felt intensities exceeding MMI 7.
- To the right of the intensity map is a figure from Duman and Emre (2013). This shows the historic earthquakes along the EAF.
- In the lower right corner is a map that shows the faults in the region. Note how the topography reflects the tectonics.
- In the lower center lerft is a plot that shows how the shaking intensity models and reports relate to each other. The horizontal axis is distance from the earthquake and the vertical axis is shaking intensity (using the MMI scale, just like in the map to the right: these are the same datasets).
I include some inset figures. Some of the same figures are located in different places on the larger scale map below.
- Here is the map with a month’s seismicity plotted.
- Here is the map with a day’s seismicity plotted (prepared a few hours after the main shock).
- There are some additional inset figures here:
- The USGS Finite Fault Model (FFM) is shown on center right. This graphic shows how much the USGS model suggests that the fault slipped during this earthquake. Learn more about the USGS Finite Fault Models here.
- To the right of the legend are two maps that show (left) liquefaction susceptibility and (right) landslide probability. These are based on empirical models from the USGS that show the chance an area may have experienced these processes that may have happened as a result of the ground shaking from the earthquake. I spend more time explaining these types of models and what they represent in this Earthquake Report for the recent event in Albania.
- I include a plot of the tide gage data from Erdemli.
- Here is the map with about a day’s seismicity plotted.
- I plot the 2023 earthquakes in blue and the 2020 earthquakes in green.
- Here is the same two maps with about 3 day’s seismicity plotted. There are other modest changes.
- I updated the aftershock map that now includes about 2 weeks of aftershocks from CSEM-EMSC.
- This also includes the faults mapped by the USGS (Reitman et a., 2023).
- Below I also added a comparison of the USGS ground failure and intensity data between the ’20 M 6.7 and the ’22 M 7.5 & M 7.8 earthquakes.
- I updated the aftershock map that now includes about 3 weeks of aftershocks from CSEM-EMSC.
- This also includes the faults mapped by the USGS (Reitman et a., 2023).
- The USGS does not have a mechanism for the M 6.7, so I am using the INGV focal mechanism from here: https://www.emsc-csem.org/Earthquake/earthquake.php?id=1218449
UPDATE: 6 February 2023
UPDATE: 8 February 2023
UPDATE: 14 February 2023
I updated some of the content below including slip rate estimates, probabilistic seismic hazard assessment for the EAF, stress modeling following the 2020 M 6.7 earthquake, and information about the Dead Sea fault.
UPDATE: 15 February 2023
UPDATE: 27 February 2023
- This is the plate tectonic map from Armijo et al., 1999.
- Here is the tectonic map from Dilek and Sandvol (2009).
- This is the Woudloper (2009) tectonic map of the Mediterranean Sea. The yellow/orange band represents the Alpide Belt, a convergent plate boundary that extends from western Europe, through the Middle East, beneath northern India and Nepal (forming the Himalayas), through Indonesia, terminating east of Australia.
- Below is a series of figures from Jolivet et al. (2013). These show various data sets and analyses for Greece and Turkey.
- Upper Panel (A): This is a tectonic map showing the major faults and geologic terranes in the region. The fault possibly associated with today’s earthquake is labeled “Neo Tethys Suture” on the map, for the Eastern Anatolia fault.
- Lower Panel (B): This shows historic seismicity for the region. Note the general correlation with the faults in the upper panel.
- Upper Panel (C): These red arrows are Global Positioning System (GPS) velocity vectors. The velocity scale vector is in the lower left corner. The main geodetic (study of plate motions and deformation of the earth) signal here is the westward motion of the North Anatolian fault system as it rotates southward as it traverses Greece. The motion trends almost south near the island of Crete, which is perpendicular to the subduction zone.
- Lower Panel (D): This map shows the region of mid-Cenozoic (Oligo-Miocene) extension (shaded orange). It just happens that there is still extension going on in parts of this prehistoric extension.
- Upper Panel (E): This map shows where the downgoing slab may be located (in blue), along with the volcanic centers associated with the subduction zone in the past.
- Lower Panel (F): This map shows the orientation of how seismic waves orient themselves differently in different places (anisotropy). We think seismic waves travel in ways that reflects how tectonic strain is stored in the earth. The blue lines show the direction of extension in the asthenosphere, green lines in the lithospheric mantle, and red lines for the crust.
- Upper Panel (G): This is the map showing focal mechanisms in the poster above. Note the strike slip earthquakes associated with the North Anatolia and East Anatolia faults and the thrust/reverse mechanisms associated with the thrust faults.
- Here are some interesting seismicity plots from Bulut et al., 2012.
- The upper two panels show the faults, earthquake epicenters, depth profile locations, and the names of the EAF fault segments.
- The lower panels show the seismicity plotted relative to depth, for each of the 5 profiles.
- Here is a map showing tectonic domains (Taymaz et al., 2007).
- Here is a tectonic overview figure from Duman and Emre, 2013.
- This is a map that shows the subdivisions of the EAF (Duman and Emre, 2013). Note Lake Hazar for reference.
- This map shows the fault mapping from Duman and Emre, 2013. Note Lake Hazar for reference. We can see some of the thrust faults mapped as part of the Southeast Anatolia fault zone.
- This is the figure from Duman and Emre (2013) that shows the spatial extent for historic earthquakes on the EAF.
- Aktug et al. (2016) used GPS observations to evaluate the plate motion rates along the EAF.
- The following two figures show the plate motion vectors and profiles of the plate velocities across the fault zone in three locations (a, b, and c).
- They used GPS data from different studies, which is the reason the vectors have different colors.
- These are the 3 GPS velocity profiles from Aktug et al. (2016) shown on the above map.
- The panels on the left represent their estimates for the slip rate of the EAF relative to the locking depth for the EAF.
- The panels on the right show how the GPS velocities change across the fault zone in these 3 areas. The velocities are measured parallel to the fault.
- Using profile a as an example, on the ight side of the fault, the velocity is held to be about 0 mm per year. As we cross the fault, the velocity jumps up to about 10 mm/year. So, the slip rate of the EAF zone across the profiles a, b, and c are about 10, 7, and 12 mm/year. As a reference, the San Andreas fault in California has a slip rate of about 25 mm/year.
- Ferry et al. (2011) used a 14,000 year long record of prehistoric earthquakes to evaluate the episodic behavior of the Dead Sea fault (DSF).
- This first map show the DSF, GPS site velocities, and geological slip rates in different locations. The DSF eventually turns into the EAF.
- This map (Ferry et al., 2011) shows the historic seismicity for this region with earthquake mechanisms for some of the earthquakes.
- Here is a figure that shows a more detailed comparison between the modeled intensity and the reported intensity. Both data use the same color scale, the Modified Mercalli Intensity Scale (MMI). More about this can be found here. The colors and contours on the map are results from the USGS modeled intensity. The DYFI data are plotted as colored dots (color = MMI, diameter = number of reports). In addition to what I write below, the data on the left are from the M 7.5 and the data on the right are from the M 7.8.
- In the upper panel is the USGS Did You Feel It reports map, showing reports as colored dots using the MMI color scale. Underlain on this map are colored areas showing the USGS modeled estimate for shaking intensity (MMI scale).
- In the lower panel is a plot showing MMI intensity (vertical axis) relative to distance from the earthquake (horizontal axis). The models are represented by the green and orange lines. The DYFI data are plotted as light blue dots. The mean and median (different types of “average”) are plotted as orange and purple dots. Note how well the reports fit the green line, the orange line, or neither line. What reasons can you think that may be explain these real observation deviations from the models.
- Below the lower plot is the USGS MMI Intensity scale, which lists the level of damage for each level of intensity, along with approximate measures of how strongly the ground shakes at these intensities, showing levels in acceleration (Peak Ground Acceleration, PGA) and velocity (Peak Ground Velocity, PGV).
- Here is a comparison between these three earthquakes from 2020 and 2022.
- The scale and spatial extent for each map is the same.
- There are many different ways in which a landslide can be triggered. The first order relations behind slope failure (landslides) is that the “resisting” forces that are preventing slope failure (e.g. the strength of the bedrock or soil) are overcome by the “driving” forces that are pushing this land downwards (e.g. gravity). The ratio of resisting forces to driving forces is called the Factor of Safety (FOS). We can write this ratio like this:
FOS = Resisting Force / Driving Force
- When FOS > 1, the slope is stable and when FOS < 1, the slope fails and we get a landslide. The illustration below shows these relations. Note how the slope angle α can take part in this ratio (the steeper the slope, the greater impact of the mass of the slope can contribute to driving forces). The real world is more complicated than the simplified illustration below.
- Landslide ground shaking can change the Factor of Safety in several ways that might increase the driving force or decrease the resisting force. Keefer (1984) studied a global data set of earthquake triggered landslides and found that larger earthquakes trigger larger and more numerous landslides across a larger area than do smaller earthquakes. Earthquakes can cause landslides because the seismic waves can cause the driving force to increase (the earthquake motions can “push” the land downwards), leading to a landslide. In addition, ground shaking can change the strength of these earth materials (a form of resisting force) with a process called liquefaction.
- Sediment or soil strength is based upon the ability for sediment particles to push against each other without moving. This is a combination of friction and the forces exerted between these particles. This is loosely what we call the “angle of internal friction.” Liquefaction is a process by which pore pressure increases cause water to push out against the sediment particles so that they are no longer touching.
- An analogy that some may be familiar with relates to a visit to the beach. When one is walking on the wet sand near the shoreline, the sand may hold the weight of our body generally pretty well. However, if we stop and vibrate our feet back and forth, this causes pore pressure to increase and we sink into the sand as the sand liquefies. Or, at least our feet sink into the sand.
- Below is a diagram showing how an increase in pore pressure can push against the sediment particles so that they are not touching any more. This allows the particles to move around and this is why our feet sink in the sand in the analogy above. This is also what changes the strength of earth materials such that a landslide can be triggered.
- Below is a diagram based upon a publication designed to educate the public about landslides and the processes that trigger them (USGS, 2004). Additional background information about landslide types can be found in Highland et al. (2008). There was a variety of landslide types that can be observed surrounding the earthquake region. So, this illustration can help people when they observing the landscape response to the earthquake whether they are using aerial imagery, photos in newspaper or website articles, or videos on social media. Will you be able to locate a landslide scarp or the toe of a landslide? This figure shows a rotational landslide, one where the land rotates along a curvilinear failure surface.
- Here is an excellent educational video from IRIS and a variety of organizations. The video helps us learn about how earthquake intensity gets smaller with distance from an earthquake. The concept of liquefaction is reviewed and we learn how different types of bedrock and underlying earth materials can affect the severity of ground shaking in a given location. The intensity map above is based on a model that relates intensity with distance to the earthquake, but does not incorporate changes in material properties as the video below mentions is an important factor that can increase intensity in places.
- If we look at the map at the top of this report, we might imagine that because the areas close to the fault shake more strongly, there may be more landslides in those areas. This is probably true at first order, but the variation in material properties and water content also control where landslides might occur.
- There are landslide slope stability and liquefaction susceptibility models based on empirical data from past earthquakes. The USGS has recently incorporated these types of analyses into their earthquake event pages. More about these USGS models can be found on this page.
- Below is a figure that shows both landslide probability and liquefaction susceptibility maps for this M 7.8 earthquake.
- Below is a figure that compares both landslide probability and liquefaction susceptibility maps for these three earthquakes.
- The scale for each map is the same.
Some Relevant Discussion and Figures
Tectonic setting of continental extrusion in eastern Mediterranean. Anatolia-Aegean block escapes westward from Arabia-Eurasia collision zone, toward Hellenic subduction zone. Current motion relative to Eurasia (GPS [Global Positioning System] and SLR [Satellite Laser Ranging] velocity vectors, in mm/yr, from Reilinger et al., 1997). In Aegean, two deformation regimes are superimposed (Armijo et al., 1996): widespread, slow extension starting earlier (orange stripes, white diverging arrows), and more localized, fast transtension associated with later, westward propagation of North Anatolian fault (NAF). EAF—East Anatolian fault, K—Karliova triple junction, DSF—Dead Sea fault,NAT—North Aegean Trough, CR—Corinth Rift.Box outlines Marmara pull-apart region, where North Anatolian fault enters Aegean.
Tectonic map of the Aegean and eastern Mediterranean region showing the main plate boundaries, major suture zones, fault systems and tectonic units. Thick, white arrows depict the direction and magnitude (mm a21) of plate convergence; grey arrows mark the direction of extension (Miocene–Recent). Orange and purple delineate Eurasian and African plate affinities, respectively. Key to lettering: BF, Burdur fault; CACC, Central Anatolian Crystalline Complex; DKF, Datc¸a–Kale fault (part of the SW Anatolian Shear Zone); EAFZ, East Anatolian fault zone; EF, Ecemis fault; EKP, Erzurum–Kars Plateau; IASZ, Izmir–Ankara suture zone; IPS, Intra–Pontide suture zone; ITS, Inner–Tauride suture; KF, Kefalonia fault; KOTJ, Karliova triple junction; MM, Menderes massif; MS, Marmara Sea; MTR, Maras triple junction; NAFZ, North Anatolian fault zone; OF, Ovacik fault; PSF, Pampak–Sevan fault; TF, Tutak fault; TGF, Tuzgo¨lu¨ fault; TIP, Turkish–Iranian plateau (modified from Dilek 2006).
A: Tectonic map of the Aegean and Anatolian region showing the main active structures
(black lines), the main sutures zones (thick violet or blue lines), the main thrusts in the Hellenides where they have not been reworked by later extension (thin blue lines), the North Cycladic Detachment (NCDS, in red) and its extension in the Simav Detachment (SD), the main metamorphic units and their contacts; AlW: Almyropotamos window; BD: Bey Daglari; CB: Cycladic Basement; CBBT: Cycladic Basement basal thrust; CBS: Cycladic Blueschists; CHSZ: Central Hellenic Shear Zone; CR: Corinth Rift; CRMC: Central Rhodope Metamorphic Complex; GT: Gavrovo–Tripolitza Nappe; KD: Kazdag dome; KeD: Kerdylion Detachment; KKD: Kesebir–Kardamos dome; KT: Kephalonia Transform Fault; LN: Lycian Nappes; LNBT: Lycian Nappes Basal Thrust; MCC: Metamorphic Core Complex; MG: Menderes Grabens; NAT: North Aegean Trough; NCDS: North Cycladic Detachment System; NSZ: Nestos Shear Zone; OlW: Olympos Window; OsW: Ossa Window; OSZ: Ören Shear Zone; Pel.: Peloponnese; ÖU: Ören Unit; PQN: Phyllite–Quartzite Nappe; SiD: Simav Detachment; SRCC: South Rhodope Core Complex; StD: Strymon Detachment; WCDS: West Cycladic Detachment System; ZD: Zaroukla Detachment. B: Seismicity. Earthquakes are taken from the USGS-NEIC database. Colour of symbols gives the depth (blue for shallow depths) and size gives the magnitude (from 4.5 to 7.6).
C: GPS velocity field with a fixed Eurasia after Reilinger et al. (2010) D: the domain affected by distributed post-orogenic extension in the Oligocene and the Miocene and the stretching lineations in the exhumed metamorphic complexes.
E: The thick blue lines illustrate the schematized position of the slab at ~150 km according to the tomographic model of Piromallo and Morelli (2003), and show the disruption of the slab at three positions and possible ages of these tears discussed in the text. Velocity anomalies are displayed in percentages with respect to the reference model sp6 (Morelli and Dziewonski, 1993). Coloured symbols represent the volcanic centres between 0 and 3 Ma after Pe-Piper and Piper (2006). F: Seismic anisotropy obtained from SKS waves (blue bars, Paul et al., 2010) and Rayleigh waves (green and orange bars, Endrun et al., 2011). See also Sandvol et al. (2003). Blue lines show the direction of stretching in the asthenosphere, green bars represent the stretching in the lithospheric mantle and orange bars in the lower crust.
G: Focal mechanisms of earthquakes over the Aegean Anatolian region.
Epicentral map and depth sectional views for seismicity along the EAFZ obtained in this study based on (a, c) absolute locations and (b, d) double-difference derived relative locations, respectively. Black dots represent earthquake locations and the gray lines are presently active faults. Selected NWSE trending transects indicated in Figures 6a and 6b and plotted as depth sections in Figures 6c and 6d.
Fault Mapping
Schematic map of the principal tectonic settings in the Eastern Mediterranean. Hatching shows areas of coherent motion and zones of distributed deformation. Large arrows designate generalized regional motion (in mm a21) and errors (recompiled after McClusky et al. (2000, 2003). NAF, North Anatolian Fault; EAF, East Anatolian Fault; DSF, Dead Sea Fault; NEAF, North East Anatolian Fault; EPF, Ezinepazarı Fault; CTF, Cephalonia Transform Fault; PTF, Paphos Transform Fault.
The main fault systems of the AN–AR and TR–AF plate boundaries (modified from Sengor & Yılmaz 1981; Saroglu et al. 1992a, b; Westaway 2003; Emre et al. 2011a, b, c). Arrows indicate relative plate motions (McClusky et al. 2000). Abbreviations: AN, Anatolian microplate; AF, African plate; AR, Arabian plate; EU, Eurasian plate; NAFZ, North Anatolian Fault Zone; EAFZ, East Anatolian Fault Zone; DSFZ, Dead Sea Fault Zone; MF; Malatya Fault, TF, Tuzgo¨lu¨ fault; EF, Ecemis¸ fault; SATZ, Southeast Anatolian Thrust Zone; SS, southern strand of the EAFZ; NS, northern strand of the EAFZ.
Map of the East Anatolian strike-slip fault system showing strands, segments and fault jogs. Abbreviations: FS, fault Segment; RB, releasing bend; RS, releasing stepover; RDB, restraining double bend; RSB, restraining bend; PB, paired bend; (1) Du¨zic¸i–Osmaniye fault segment; (2) Erzin fault segment; (3) Payas fault segment; (4) Yakapınar fault segment; (5) C¸ okak fault segment; (6) Islahiye releasing bend; (7) Demrek restraining stepover; (8) Engizek fault zone; (9) Maras¸ fault zone.
Map of the (a) Palu and (b) Puturge segments of the East Anatolian fault. Abbreviations: LHRB, Lake Hazar releasing bend; PS, Palu segment; ES, Erkenek segment; H, hill; M, mountain; C, creek; (1) left lateral strike-slip fault; (2) normal fault; (3) reverse or thrust fault; (4) East Anatolian Fault; (5) Southeastern Anatolian Thrust Zone; (6) syncline;(7) anticline; (8) undifferentiated Holocene deposits; (9) undifferentiated Quaternary deposits; (10) landslide.
Surface ruptures produced by large earthquakes during the 19th and 20th centuries along the EAF. Data from Arpat (1971), Arpat and S¸arog˘lu (1972), Seymen and Aydın (1972), Ambraseys (1988), Ambraseys and Jackson (1998), Cetin et al. (2003), Herece (2008), Karabacak et al. (2011) and this study. Ruptured fault segments are highlighted.
Slip Rates
The GPS observations employed in this study. The velocity error ellipses are at 95% confidence level. The dashed rectangles show the profiles for investigating the trade-off between the slip rate and the locking depth.
The variability of the slip rates w.r.t. the locking depth (red) and the χ2 values of the estimation (black). The thick grey bands show 2-s error bounds of the slip rates for profiles a to c (left panel) and the velocity profiles with slip rate and locking depth estimated simultaneously (right panel). The red curve shows the model fit to the GPS data (open circles with error bars at 95% confidence level) and the blue curve is the fault parallel shear strain rate for the best fit model determined from the analysis shown in Figure 3 and described in the text.
a) General map of the Dead Sea Transform system. Numbers are geological slip rates (in black) and geodetic strain rates (in white). Sources: Klinger et al. (2000); Niemi et al. (2001); Meghraoui et al. (2003); Reilinger et al. (2006); Ferry et al. (2007). Pull-apart basins: ab, Amik basin; gb, Ghab basin; hb, Hula basin; ds, Dead Sea. Major fault segments: EAF, East Anatolian fault; AF, Afrin fault; KF, Karasu fault; JSF, Jisr Shuggur fault; MF, Missyaf fault; YF, Yammouneh fault; ROF, Roum fault; RAF, Rachaya fault; SF, Serghaya fault; JVF, Jordan Valley fault; WAF, Wadi Araba fault. (b) Detailed map of the JVF segment between the Sea of Galilee and the Dead Sea. The segment itself is organized as six 15-km to 30-km-long right-stepping subsegments limited by 2-km to 3-km-wide transpressive relay zones. The active trace of the JVF continues for a further ∼10 km northward into the Sea of Galilee (SG) and ∼20 km southward into the northern Dead Sea (DS). The color version of this figure is available only in the electronic edition.
Seismicity of the Dead Sea Transform system. Instrumental events with M ≥4 from 1964 to 2006 (IRIS Data Management Center; see Data and Resources section) in filled circles. Background seismicity is very scarce and mainly restricted to the Lebanese Bend and the Jordan Valley. The 1995 Mw 7.3 Aqaba earthquake and aftershock swarm dominate the seismicity of the Red Sea basin. Historical events with I0 ≥ VII (Ambraseys and Jackson, 1998; Sbeinati et al., 2005) in open circles. Apart from the 1927 Mw 6.2 Jericho earthquake, no significant event has occurred along the JVF since A.D. 1033 (see text for details).
Shaking Intensity
Earthquake Triggered Landslides
- There is a seminal paper (Wells and Coppersmith, 1994) where these geologists compiled the existing data from global earthquakes.
- They extracted different aspects of the physical size of these earthquakes so that they could develop relations between the earthquake size (e.g., length of the fault that ruptured the surface of the Earth) and earthquake magnitude. Since these relations are based on real data from real earthquakes, we call these empirical scaling relations (i.e., the size of the earthquake slip “scales” with the size of the magnitude).
- Their analyses also subdivided the earthquakes in ways to see if different types of earthquakes (strike-slip, normal, or thrust/reverse) had different scaling relations.
- Some have updated the database of earthquake observations. However, these updated scaling relations are not that much different than the original Wells and Coppersmith (1994) scaling relations. Perhaps there is sufficient variation in earthquake size that we have yet to deconvolve all the variation in fault ruptures?
- Below I present the Wells and Coppersmith (1994) scaling relations for subsurface earthquake slip length. I do this because it may be a while until we have a good estimate for other measures (like surface rupture length) but we can estimate the subsurface fault length in different ways with existing data (like the spatial extent of aftershocks).
- In the upper panel I list the rough length of three fault segments that are part of the East Anatolia fault system.
- I use the relations represented by the diagonal lines in the center panel to calculate the earthquake magnitude for faults of varying length (100-200km). Based on their relations, a magnitude M 7.8 earthquake may have ruptured a fault with a subsurface length of 200 km.
Fault Scaling Relations
Seismic Hazard and Seismic Risk
- These are the two seismic maps from the Global Earthquake Model (GEM) project, the GEM Seismic Hazard and the GEM Seismic Risk maps from Pagani et al. (2018) and Silva et al. (2018).
- The GEM Seismic Hazard Map:
- The Global Earthquake Model (GEM) Global Seismic Hazard Map (version 2018.1) depicts the geographic distribution of the Peak Ground Acceleration (PGA) with a 10% probability of being exceeded in 50 years, computed for reference rock conditions (shear wave velocity, VS30, of 760-800 m/s). The map was created by collating maps computed using national and regional probabilistic seismic hazard models developed by various institutions and projects, and by GEM Foundation scientists. The OpenQuake engine, an open-source seismic hazard and risk calculation software developed principally by the GEM Foundation, was used to calculate the hazard values. A smoothing methodology was applied to homogenise hazard values along the model borders. The map is based on a database of hazard models described using the OpenQuake engine data format (NRML). Due to possible model limitations, regions portrayed with low hazard may still experience potentially damaging earthquakes.
- Here is a view of the GEM seismic hazard map for Europe.
- The USGS Seismic Hazard Map:
- Here is a map that displays an estimate of seismic hazard for the region (Jenkins et al., 2010). This comes from Giardini et al. (1999).
- The GEM Seismic Risk Map:
- The Global Seismic Risk Map (v2018.1) presents the geographic distribution of average annual loss (USD) normalised by the average construction costs of the respective country (USD/m2) due to ground shaking in the residential, commercial and industrial building stock, considering contents, structural and non-structural components. The normalised metric allows a direct comparison of the risk between countries with widely different construction costs. It does not consider the effects of tsunamis, liquefaction, landslides, and fires following earthquakes. The loss estimates are from direct physical damage to buildings due to shaking, and thus damage to infrastructure or indirect losses due to business interruption are not included. The average annual losses are presented on a hexagonal grid, with a spacing of 0.30 x 0.34 decimal degrees (approximately 1,000 km2 at the equator). The average annual losses were computed using the event-based calculator of the OpenQuake engine, an open-source software for seismic hazard and risk analysis developed by the GEM Foundation. The seismic hazard, exposure and vulnerability models employed in these calculations were provided by national institutions, or developed within the scope of regional programs or bilateral collaborations.
- Here is a view of the GEM seismic risk map for Europe.
- Probabilistic Seismic Hazard Assessment – East Anatolia fault
- Gülerce et al. (2017) conducted a Probabilistic Seismic Hazard Assessment (PSHA) for the EAF. I hope you are keeping up with all the acronyms in this report.
- A PSHA is basically a way of taking information about earthquake recurrence (from paleoseismology, seismicity rates, geodesy, etc.) for faults in a given region and using this information to make estimates of the likelihood (the chance) of a certain measure of ground shaking that might be exceeded over a period of time.
- The California Geological Survey has a website that provides an overview of what PSHA is and how it is conducted.
- A key part of PSHA is the incorporation of all possible and probable earthquakes for the faults in the analysis region. People conducting PSHA use a “logic tree” to organize this variation. Each branch of the logic tree is given a weight that the experts think that that branch is most likely to happen.
- Here is the logic tree presented by Gülerce et al. (2017).
- Of the many products that can come from a PSHA, the principal output are a series of maps that show the chance that ground shaking levels will be exceeded. E.g., a map that shows a 10% chance of being exceeded in 50 years (in other words, the chance that this ground shaking might happen in 475 years; aka the 475 year return period ground shaking map).
- There are lots of parameters that we use to calculate the ground shaking, such as the seismic velocity structure of the Earth (e.g., the Vs30, the seismic velocity of the upper 30 meters of the Earth).
- Here is the table showing the fault parameters for the faults used in this PSHA.
- These first maps are the 475 year return period maps (10% in 50 years) for Vs30 = 760 m/second (“softer” rock) and Vs30 = 1100 m/second (“harder” rock).
- These maps are the 2475 year return period maps (2% in 50 years) for Vs30 = 760 m/second (“softer” rock) and Vs30 = 1100 m/second (“harder” rock).
The Global Seismic Hazard Map. Peak ground acceleration (pga) with a 10% chance of exceedance in 50 years is depicted in m/s2. The site classification is rock everywhere except Canada and the United States, which assume rock/firm soil site classifications. White and green correspond to low seismicity hazard (0%-8%g), yellow and orange correspond to moderate seismic hazard (8%-24%g), pink and dark pink correspond to high seismicity hazard (24%-40%g), and red and brown correspond to very high seismic hazard (greater than 40%g).
PSHA map for the 475-yr return period peak ground acceleration (PGA) for (a) VS30 760 m=s and (b) VS30 1100 m=s. Contour lines (for PGA 0:4g) represent the design value for the highest earthquake zone in Turkish Earthquake Code (2007). The color version of this figure is available only in the electronic edition.
PSHA map for the 2475-yr return period PGA for (a) VS30 760 m=s and (b) VS30 1100 m=s. Contour lines (for PGA 0:6g) represent the design value for special structures for the highest earthquake zone in Turkish Earthquake Code (2007). The color version of this figure is available only in the electronic edition.
- When an earthquake fault slips, the crust surrounding the fault squishes and expands, deforming elastically (like in one’s underwear). These changes in shape of the crust cause earthquake fault stresses to change. These changes in stress can either increase or decrease the chance of another earthquake.
- I wrote more about this type of earthquake triggering for Temblor here. Head over there to learn more about “static coulomb stress triggering.”
- Lin et al. (2020) used the 24 January 2020 M 6.7 Doganyol Earthquake to investigate how the EAF slips before and after the M 6.7 mainshock.
- They also modeled the static coulomb stress changes along the EAF system following the 2020 M 6.7 earthquake.
- This map shows historic earthquakes and mechanisms, highlighting the 2020 M 6.7 event in red. (Lin et al., 2020).
- This map shows the extent for some historic earthquakes and the inset shows the change in static coulomb stress on the EAF following the 2020 M 6.7 event.
- Here are a suite of static coulomb stress changes given a range of fault parameters.
- Dr. Shinji Toda worked with Ross Stein and others to calculate static coulomb stress changes related to the M 7.8 earthquake. Here is their article and below is a video from their report.
Stress Triggering
Tectonic setting of the 2020 Doganyol earthquake. Red and black stars represent the epicenter of the 2020 earthquake and historical earthquakes, respectively. Black lines indicate the major active faults in this region, and the white box shows the projection of the fault plane. The locations of mainshock and historical earthquakes are from Kandilli Observatory and Earthquake Research Institute (KOERI; see Data and Resources) and U.S. Geological Survey (USGS) (see Data and Resources), respectively. Focal mechanisms are also plotted (see Data and Resources). The inset
shows motions of major tectonic units (Armijo et al., 1999).
Segments of the East Anatolian fault (EAF), distribution of historical earthquakes, and stress accumulation on the surrounding faults caused by the earthquake at a depth of 10 km (inset). The receiver fault is −246°=67°= − 9°. The geometry of each fault segment refers to the mechanism of the regional historical earthquake, and the effective friction coefficient is 0.4. The locations of historical earthquakes are from Ambraseys (1989), Ambraseys and Jackson (1998), Tan et al. (2008), and USGS (see Data and Resources). GCMT; Global Centroid Moment Tensor; KTJ, Karliova Triple Junction.
Stress accumulation caused by the earthquake on the surrounding faults calculated at a depth of 10 km; the dip angles are (a) 67°, (b) 47°, and (c) 87° with reference strikes fromDuman and Emre (2013). Stress accumulation caused by the earthquake on the surrounding faults calculated at (d) depths of 5 km; the geometry of each fault segment refers to the mechanism of the regional historical earthquake. The effective friction coefficient is 0.4.
- 2022.02.06 M 7.8 Turkey/Syria
- 2022.11.23 M 6.1 Turkey
- 2020.12.30 M 6.4 Croatia
- 2020.10.30 M 7.0 Turkey
- 2020.05.02 M 6.6 Crete, Greece
- 2020.01.24 M 6.7 Turkey
- 2019.11.26 M 6.4 Albania
- 2018.10.25 M 6.8 Greece
- 2017.07.20 M 6.7 Turkey
- 2017.06.12 M 6.3 Turkey/Greece
- 2016.10.30 M 6.6 Italy
- 2016.10.30 M 6.6 Italy Update #1
- 2016.10.28 M 5.8 Tyrrhenian Sea
- 2016.10.26 M 6.1 Italy
- 2016.10.16 M 5.3 Greece/Albania
- 2016.08.23 M 6.2 Italy
- 2016.01.24 M 6.1 Mediterranean
- 2015.11.17 M 6.5 Greece
- 2015.04.16 M 6.0 Crete
Europe
General Overview
Earthquake Reports
Social Media
Original Thread:
#EarthquakeReport for M7.8 #Deprem #Earthquake in #Turkey near #Syria
Felt intensity MMI 8
Sadly many will likely sufferRead more abt regional tectonics here https://t.co/3vFCChWOo9https://t.co/g7OiqPRrKk pic.twitter.com/3wUMjXIXzl
— Jason "Jay" R. Patton (@patton_cascadia) February 6, 2023
#EarthquakeReport for M7.8 #Deprem #Earthquake in #Turkey near #Syria
largest magnitude earthquake in Turkey since 1939 M 7.8
southwest of 24 jan '20 M 6.7
small tsunami in Erdemlireport here (and will continue to update)https://t.co/HIrvdxepUn pic.twitter.com/H3f187sijL
— Jason "Jay" R. Patton (@patton_cascadia) February 6, 2023
Aftershock zone of today's M7.8 #earthquake in SE Turkey extend for ~250km along the East Anatolian Fault system. That left-lateral fault system bounds the Anatolian tectonic microplate to the east. pic.twitter.com/tsq5YqoWpa
— Robin Lacassin – @RobinLacassin@qoto.org (@RLacassin) February 6, 2023
Damaging M7.8 EQ hit southern Turkey near the Syrian border ~4am local time. PAGER is red for this event; extensive damage is probable. Our hearts go out to those affected. See @Kandilli_info for local info. https://t.co/dMyc6ZVrE1 https://t.co/0OxrznZf1v pic.twitter.com/eco071JqVm
— USGS Earthquakes (@USGS_Quakes) February 6, 2023
The distance between the two blue markers in this map is ~330km. Some events to the SW could be on separate faults, events further to the NE may be triggered (???) or around the end of a (very long) main rupture (???). https://t.co/RHimY8B2g4 pic.twitter.com/DUROJZC6qd
— Anthony Lomax 😷🇪🇺🌍🇺🇦 (@ALomaxNet) February 6, 2023
Some tectonic background on today's M 7.8 #earthquake on (or just off?) the East Anatolian Fault (EAF) in #Turkey 🇹🇷. Figure updated from @Lea_Coromoto's recent GRL paper (https://t.co/xbMdGGyYoO). 🧵 pic.twitter.com/OY71CPvrVw
— Dr. Edwin Nissen (@faulty_data) February 6, 2023
#EarthquakeReport for M7.8 #Deprem #Earthquake in #Turkey near #Syria
reported intensities at least MMI 9!
hopefully international aid arrives soon!report here (and will continue to update)https://t.co/HIrvdxepUn pic.twitter.com/m8gCVoelFH
— Jason "Jay" R. Patton (@patton_cascadia) February 6, 2023
#EarthquakeReport for M7.8 #Deprem #Earthquake in #Turkey and #Syria
the difference in global eq catalog and a more local one (56 vs. 285 events)https://t.co/rFzezAxn5mhttps://t.co/1Ujy0bsZZd
read about this sequence here (will keep updating this) https://t.co/HIrvdxepUn pic.twitter.com/voOC221T4R
— Jason "Jay" R. Patton (@patton_cascadia) February 6, 2023
#EarthquakeReport & #TsunamiReport for M7.8 #Deprem #Earthquake in #Turkiye #Turkey #Syria
updated poster w/tide gage plot
aftershocks from 1 day compared w '20 M6.8
sequence
many faults involved in sequenceread more in report (will continue to update)https://t.co/HIrvdxepUn pic.twitter.com/Asq8YdNsJ4
— Jason "Jay" R. Patton (@patton_cascadia) February 7, 2023
#EarthquakeReport for M7.8/7.5 Pazarcik/Elbistan #Deprem #Earthquake in #Turkiye #Turkey #Syria
updated aftershock map w/@USGS_Quakes interp & AFEAD faults
ground failure & intensity comparison w/'20 M6.7updated and continuing to update report https://t.co/HIrvdxepUn pic.twitter.com/Cf1592F1Oe
— Jason "Jay" R. Patton (@patton_cascadia) February 16, 2023
Coseismic displacements from GPS PPP @ResusScience results of February 6, 2023 Mw7.8 (red star and arrows) and Mw7.6 (blue star and arrows) earthquakes in Maraş Turkey @Tubitak @ProfHasanMandal @profugurdogan @sergintav @AktifTektonik @etayruk @ilayfarimaz @geodesist_a pic.twitter.com/vHticEw9N1
— Seda Özarpacı (@sedaozarpaci) February 8, 2023
On it! Azimuth offsets. pic.twitter.com/SfrGAXPx8T
— Danielle Lindsay (@DLindsay_EQ) February 9, 2023
Pixel tracking of @planet satellite images shows fault rupture of Mw 7.8 in Turkey extends through and past Kirikhan, not clear where southern rupture termination occurs. Displacement varies from 2-4 m (1/2).
You can access fault mapping from here https://t.co/1eOHTT4LsD
(1/2) pic.twitter.com/dRS1VuPUPa
— Dr. Chris Milliner (@Geo_GIF) February 9, 2023
Here's @temblor's preliminary Coulomb stress analysis for the 2023 Türkiye earthquakes that can help understand *where* aftershocks are most likely (but not when or how big).
Article by @EeWkKI8KqQLHUqz @rstein357 et al. https://t.co/Xed6yOyySU
— temblor (@temblor) February 9, 2023
Prelim. observations of fault rupture in Turkey EQ sequence using satellite images & radar data. This provides a first estimate of surface rupture length– over 300 km (~185 mi) from both EQs. We expect to see more of the rupture as data become available @USGS_HDDS @DisastersChart pic.twitter.com/A9xQ5nG27d
— USGS Earthquakes (@USGS_Quakes) February 9, 2023
(1/2) Preliminary displacement maps from ALOS-2 descending track 78, acquired between 2022/04/06 and 2023/02/08 in radar line-of-sight, for the Mw 7.8 (February 6, 2023) main shock near the city of Nurdagi, Turkey, followed by Mw 7.5 aftershock within 9 hours. pic.twitter.com/lMcc8gn5YI
— Advanced Rapid Imaging & Analysis (ARIA) (@aria_hazards) February 9, 2023
It appears half of the Mw 7.8 Turkey surface rupture has been imaged with satellite data. This shows surface motion combining Sentinel-2 optical offsets from @NERC_COMET with ALOS-2 radar from @aria_hazards projected into NNE direction. Rupture terminates south of Kirikhan pic.twitter.com/djmMFZ0ZFJ
— Dr. Chris Milliner (@Geo_GIF) February 9, 2023
The range offset map from Sentinel-1 shows the two ruptures clearly
Data available athttps://t.co/IzMLypaBF7
We should have complete coverage for this terrible event by tomorrow morning. The scale of the event is frightening and our thoughts go out to everyone in the area. pic.twitter.com/lCanGRFAZ4
— NERC COMET (@NERC_COMET) February 9, 2023
The same North-South displacement field with fault trace overlay (from MTA 250K fault maps) 2/2 pic.twitter.com/L7pTLLhIKj
— Sotiris Valkaniotis (@SotisValkan) February 9, 2023
#Sentinel-1 Descending interferogram/ ground range, LOS displacement maps, and 3D displacement views (exaggerated) of the 06.02.2023 #Kahramanmaras #TurkeySyriaEarthquake . #InSAR data obtained from @NERC_COMET / @COMET_database@ISIK_VEYSEL @caglayanayse @AnkaraUni #deprem pic.twitter.com/r1WGK2ZOy9
— Reza Saber (@Geo_Reza) February 12, 2023
Today's M7.8 earthquake in Turkey occurred in the East Anatolian Fault zone.
Although this fault is a known hazard, the quake is unusual. Today's M7.8 released >2x as much energy as the largest recorded quakes in the region (M7.4).
Image credit: Kyle Bradley
— Dr. Judith Hubbard (@JudithGeology) February 6, 2023
During the night, terrible M7.8 #earthquake along the East Anatolian Fault zone, in Turkey, near border with Syria, felt over a very wide area.
Death toll >300, possibly will increase.https://t.co/Pb79TMQE0lhttps://t.co/vtyMMQO8NO
As in 1114
👇https://t.co/ZpBPQz3ela pic.twitter.com/9gavMmVrG2— José R. Ribeiro (@JoseRodRibeiro) February 6, 2023
Major M7.8, shallow, lateral slip #earthquake on S Anatolian Fault of European-Arabian convergence zone. Significant surface shaking with major surface and societal impact in densely populated area.#Turkey. https://t.co/qxeUaGEv6m pic.twitter.com/SSWH4n9aR8
— 🌎 Prof Ben van der Pluijm ⚒️ (@vdpluijm) February 6, 2023
The 6 February 2023 Mw=7.8 #earthquake near #Nurdağı in #Gaziantep, #Turkey is likely to have triggered substantial numbers of landslides:- https://t.co/6JNBwwEvkJ #TurkeyEarthquake pic.twitter.com/Z6HnYqwa69
— Dave Petley (@davepetley) February 6, 2023
Mw ~7.8 Nurdağı earthquake, Turkey aligns with a rapidly deforming mantle region compatible with left-lateral shear on the East Anatolian Fault. The fault broke in piecemeal ruptures in the past. Today's earthquake connected multiple segments https://t.co/oVXH18azgh pic.twitter.com/aMONEdrXBg
— Sylvain Barbot (@quakephysics) February 6, 2023
Artçı #deprem dağılımı ve segment uzunluğu esas alındığında, 06.02.2023, 04:17 Mw=7.8 depreminde 150 km uzunlukta bir yırtılma olduğu tahmin edilebilir.#Pazarcık#Maraş#Hatay#Antakya#nurdağı pic.twitter.com/QG5rGhLf2F
— Dr. Ramazan Demirtaş (@Paleosismolog) February 6, 2023
Türkei / Syrien: Opferzahl steigt auf 604 mit über 3000 Verletzten und einer unbekannten Anzahl an Vermissten.
Nachbeben und Feldbeobachtungen lassen auf eine Bruchlänge von über 300 Kilometern schließen. Aktualisierte ShakeMap pic.twitter.com/1MDnqH8CPa
— Erdbebennews (@Erdbebennews) February 6, 2023
This is a visualization of the waves from the M7.8 #earthquake in #Turkey rolling through most of North America. This events and the ones that followed caused an enormous amount of damage, please consider donating to relief efforts. #deprem @EarthScope_sci pic.twitter.com/xivO7ijZDP
— UMN Seismology (@UMNseismology) February 6, 2023
This seismic trace from a seismic station in Turkey (shown by the green triangle) shows the waves from the M7.8, M7.5 and numerous aftershocks. pic.twitter.com/ObB9FmrW0G
— Wendy Bohon, PhD 🌏 (@DrWendyRocks) February 6, 2023
Automatic displacement scenario, expected #InSAR fringes and Sentinel-1 orbits & dates for the February 6 M 7.9 #Turkey #earthquake, based on USGS slip distribution.
Post-event images acquired 12 days after the pre-event.With @antandre71
*** SCENARIOS ARE NOT REAL DATA *** pic.twitter.com/35T1EGk1a9— Simone Atzori (@SimoneAtzori73) February 6, 2023
Early Photos from the Earthquake in Turkey and Syria – 28 images of the widespread damage and rescue efforts following last night's magnitude 7.8 earthquake, which claimed at least 2,100 lives. https://t.co/vxPybAqJmA pic.twitter.com/KlTu3ta0if
— The Atlantic Photo (@TheAtlPhoto) February 6, 2023
Clear cumulative left-lateral offsets of Quaternary markers on the Sürgü-Çartak Fault: here a river and alluvial terrace offset by several tens of meters (be careful, this is not the offset of today's rupture). Arrows outline fault trace. pic.twitter.com/fauhotfiDv
— Robin Lacassin – @RobinLacassin@qoto.org (@RLacassin) February 6, 2023
Seismic waves from the M7.8 (USGS) earthquake in Southern Turkey crossing Europe. Each dot is a seismic station. (GMV) https://t.co/6cY0RObbXv pic.twitter.com/SHbdkxQXzD
— Nahel Belgherze (@WxNB_) February 6, 2023
7.8 Mw #earthquake in #Turkey as recorded by the @GEO3BCN_CSIC SEP seismometer in Barcelona pic.twitter.com/8CoAzuTcEk
— Jordi Diaz Cusi (@JDiazCusi) February 6, 2023
This earthquake does not significantly change the possibility of an earthquake in Istanbul. This probability remains significant as a large earthquake is expected to hit the area anytime in the coming decades. So what is key is to be prepared! https://t.co/EtLJxGrnwC
— EMSC (@LastQuake) February 6, 2023
Today's M7.8 #earthquake in #Turkey also generated a #tsunami. The tsunami height is 30 cm in Erdemli (see the picture). We expect a maximum tsunami coastal runup of up to around 1.5 m (or 2 m) in some places near the epicenter. pic.twitter.com/pHTiasEroj
— Dr Mohammad Heidarzadeh (@Mo_Heidarzadeh) February 6, 2023
This TV crew was broadcasting live when a second magnitude 7.5 #earthquake hit #Turkey ⤵️
Follow @CBKNEWS #TurkeyEarthquake #Turkiye #PrayForTurkey pic.twitter.com/ebA1QmxgkA
— CBKNEWS (@CBKNEWS121) February 6, 2023
Just awoke to see there was a M7.5 earthquake a few hours ago in the same area as the earlier M7.8 quake. Looking at the epicenters it seems this might be a second (triggered?) fault (blue), not the East Anatolian FZ (yellow). This is devestating for this area. #Turkey #Syria pic.twitter.com/7Im5dx6jfb
— Brian Olson (@mrbrianolson) February 6, 2023
This animation shows how Anatolia (Turkey) is pushed to the west by the indentation of Arabia, during the last 10 million years or so. This is accommodated along the North and East Anatolian Faults, causing major earthquakes. @UUEarthSciences #Tectonics #GPlates pic.twitter.com/tBz3dwfqQn
— Douwe van Hinsbergen (@vanHinsbergen) May 15, 2021
🗒️Registros de máxima aceleración del suelo (PGA, en cm/s²) del sismo 7.8 Mw de Turquía🇹🇷.
Pazarcık: 1966
Adıyaman Merkez: 880
Antakya: 867
Hassa: 848
Kırıkhan: 749
Altınözü: 534
Belen: 484
Sivrice: 424
Onikişubat: 354
Türkoğlu: 353
Adaklı: 329
Bahçe: 305
Tut: 291
Fuente: AFAD pic.twitter.com/t48oGjIPZG— ASISMET (@Asismet_IF) February 6, 2023
Taiwan has sent a search team to 🇹🇷 in response to the earthquake and donated
Previously, Turkey came to the aid of Taiwan in the 1999 and was the first team to depart their country. There was a Taiwanese search team in 🇹🇷 at the time in response to the 1999 Izmit earthquake. pic.twitter.com/f4Em2AB6GV
— 陳彥翰 Chen Yen-Han (@chen_yenhan) February 6, 2023
Part 2: pic.twitter.com/57tcAtX3CE
— Stephen Hicks 🇪🇺 (@seismo_steve) February 6, 2023
I wouldn't have been able to get through the last 24 hours of interviews without the online resources complied by this wonderful geoscience community including @Harold_Tobin @patton_cascadia @DrWendyRocks @SquigglyVolcano @JudithGeology @DrLucyJones @CPPGeophysics & many others🙏
— Adam Pascale (@SeisLOLogist) February 7, 2023
Refugees Drown in Shipwrecks Off Coasts of Greece, Italy https://t.co/Mdmh5YYDOk
— Democracy Now! (@democracynow) February 7, 2023
The Mw 7.5 aftershock in Turkey seems to have ruptured a splay fault that extends westward from the East Anatolian Fault. I attach a fault map from Bozkurt (2001) https://t.co/bUDHG3iDSI pic.twitter.com/Sk0P9ku005
— Sylvain Barbot (@quakephysics) February 6, 2023
Following the M7.8 EQ, a M7.5 aftershock struck at ~1:30 pm local time. Significant and widespread damage is likely. More aftershocks will occur. Follow @Kandilli_info for local information. https://t.co/KLLmXlfS70 https://t.co/8wyrVPRJ9J pic.twitter.com/Kh825PfB11
— USGS Earthquakes (@USGS_Quakes) February 6, 2023
BBC News – Drone footage shows earthquake aftermath in Turkeyhttps://t.co/aZPGuU5UKl
— EMSC (@LastQuake) February 7, 2023
L’allerta tsunami per il terremoto in Turchia del 6 febbraio 2023 https://t.co/SP8KG1HvMB
— INGVterremoti (@INGVterremoti) February 6, 2023
Yes, I totally agree. Those doing preliminary fact finding are a massive part of the whole communication effort. Giving many interviews in a day is pretty stressful and time consuming so getting a clear picture and updates from Tweets is so valuable.
— Stephen Hicks 🇪🇺 (@seismo_steve) February 7, 2023
M7.8 Turkey (2023.02.06)
M7.5 Turkey (2023.02.06)https://t.co/mv8Zdvo2Hshttps://t.co/ZgIfrDhCPjRange and azimuth offsets
ALOS-2 path 78, frame 2850-2890
Imagery courtesy of JAXA and facilitated by NASA pic.twitter.com/8tx5ySxInR— gCent (@gCentBulletin) February 8, 2023
Molltrack in the east of Türkoglu. @AktifTektonik @CengizZabci @HNK390978941, Gürsel Sunal, Erdem Kırkan, Nurettin Yakupoğlu, Asen Sabuncu pic.twitter.com/mxveGjmzld
— H. Serdar Akyüz (@akyuz24) February 8, 2023
The death toll in the earthquake that struck Turkey and Syria on Monday has risen to at least 12,000, with an unknown number still missing. @JaneFerguson5 reports from Adana in Southern Turkey. https://t.co/x2wbLMyl6O pic.twitter.com/4JhthDEyYF
— PBS NewsHour (@NewsHour) February 8, 2023
YIKIMIN RESMİ !!!!
5 Şubat (Öncesi) ve 6 Şubat 2023
İnsanlarımıza MEZAR olarak inşa edilen TABUT BİNALAR!
-Ciddi "CEZAİ YAPTIRIMLAR" getirilmeli
-Suçlu ne FAY, ne DEPREM.
-Ne de #deprem BÜYÜKLÜĞÜ
-Suçlu/Sorumlular BELLİ
-YAZIKTIR. GÜNAHTIR
-Bu büyük bir VEBAL
-YETER ARTIK !! pic.twitter.com/2ftyuTu6xT— Dr. Ramazan Demirtaş (@Paleosismolog) February 8, 2023
In this episode, @NPRShortWave host @emilykwong1234 talks to geologist Wendy Bohon and @NPR science correspondent Geoff Brumfiel about why earthquake prediction is such a difficult problem, and the science behind detecting them in the first place.https://t.co/0XTOyhKmQV
— Wendy Bohon, PhD 🌏 (@DrWendyRocks) February 8, 2023
NE-SW/N-S orientated fracture systems formed within the deformation zone of the #Malatya #Fault after the second #earthquake.#TurkeyEarthquake pic.twitter.com/3DWgq05aLT
— Taylan SANÇAR (@tsancar) February 8, 2023
A damage proxy map for the M7.8 and M7.5 #earthquake that struck #Türkiye (#Turkey) and #Syria on 6 Feb 2023. From #ALOS2 satellite #SAR data acquired 2 days after the earthquakes. We hope this map will support relief efforts. More maps and information at https://t.co/XEMyD6ztqv pic.twitter.com/61WnlPUiQy
— EOS Remote Sensing (@eos_rs) February 8, 2023
Scenario update of what we expect from #InSAR data, with Sentinel-1 coverage, for both M 7+ #Earthquaketurkeysyria events combined.
Thanks @dara_berg_ (USGS) for updating the M 7.9 solution.SCENARIOS ARE PREDICTED AND NOT REAL DATA pic.twitter.com/UhiiIIgSdt
— Simone Atzori (@SimoneAtzori73) February 8, 2023
A Teachable Moment? https://t.co/hBDsTQwRmV
— Chris Goldfinger (@goldfinger300) February 9, 2023
Interesting look at how earthquake-resilient building codes are not enforced in Turkey and why we saw brand-new buildings that should've been compliant and safe crumple. https://t.co/aY4QXuMtGO
— Megan Sever (@MeganSever4) February 8, 2023
Sea level has risen in earthquake-hit city of Iskenderun, Turkey pic.twitter.com/0OS9uwANcJ
— Ragıp Soylu (@ragipsoylu) February 7, 2023
The local KOERI-RETMC seismic catalog from Boğaziçi University, Turkey, has recorded more than 1300 events since Monday – the vast majority associated with the M7.8 earthquake.
Zoom in and explore the seismic patterns here: https://t.co/DEzVNJzLoX pic.twitter.com/PkFxMDBxCx
— Dr. Judith Hubbard (@JudithGeology) February 8, 2023
Pixel offsets for Feb 6, 2023 M7.8 Turkey mainshock and M7.5 aftershock
ALOS-2 path 78, frame 2850, 2860
06/04/2022- 02/08/2023
Imagery courtesy of JAXA and facilitated by NASA pic.twitter.com/BmHoqfxTFP— Danielle Lindsay (@DLindsay_EQ) February 8, 2023
Here is the updated map of aftershocks distribution @john_galetzka https://t.co/JD9D2flHtl pic.twitter.com/bXXglWqtSB
— Ziyadin Çakır (@ziyadin) February 9, 2023
This is the footage (and see Ian’s comment) https://t.co/iNZjtbxoXX
— Stéphane Baize (@Stef_EQ_Geology) February 9, 2023
Kırığın ilk İHA tabanlı SYM’leri / First UAV-based DSMs of the surface rupture(s) @AktifTektonik @akyuz24 @HNK390978941 Gürsel Sunal, Erdem Kırkan, Asen Sabuncu, Nurettin Yakupoğlu pic.twitter.com/bq1XjqyfIf
— Cengiz Zabcı (@CengizZabci) February 9, 2023
Kırığın güney devamı; Kırıkhan’ın 9 km kuzeyi; the southern extent of the surface rupture(s), 9 km to the north of Kırıkhan @AktifTektonik @akyuz24 @HNK390978941 Gürsel Sunal, Nurettin Yakupoğlu, Erdem Kırkan, Asen Sabuncu pic.twitter.com/JFm956JAFR
— Cengiz Zabcı (@CengizZabci) February 9, 2023
Some more heartwarming footage coming out of the Turkey earthquake zone, rescuers we able to free a little friend!
(https://t.co/04q4SYvMUs) pic.twitter.com/8xPUil5gJW— 🥀_Imposter_🕸️ (@Imposter_Edits) February 8, 2023
An earthquake has only ONE magnitude, but can produce MANY different intensities of shaking.
The intensity of shaking in a given place depends on many things, including the earthquake magnitude, the distance from the quake, and the local geology. pic.twitter.com/N9mv8bkj7R
— Wendy Bohon, PhD 🌏 (@DrWendyRocks) February 8, 2023
Almost 600 aftershocks reported by @lastquake
so far#Turkey #earthquake #matplotlib #cartopy pic.twitter.com/rrPJHHVeOO— Gilles Mazet-Roux (@gmazet) February 8, 2023
Surface faulting in Hatay @earthquakeTurkey pic.twitter.com/0Cca6tSRX5
— pigall (@Pigall6) February 8, 2023
Looking a bit more closely and plotted a bit more fancily, the KOERI hypocenter (white star) plots right next to the blob along trend from that fringe, so it looks like a good call. Do we know what the first motion focal mechanism looks like? pic.twitter.com/o9wS8NpcPS
— Dr Gareth Funning (@gfun) February 9, 2023
Artçılar: AFAD, diri faylar: Emre 2013. pic.twitter.com/Mktsjh6xn8
— ATAG (@AktifTektonik) February 8, 2023
Updated @ResearchGate llink: https://t.co/9fRLqpYTTJ
Direct PDF link: https://t.co/mUxbqcHlU5 https://t.co/sY54g23UcQ
— iunio iervolino (@iuniervo) February 8, 2023
The amount of damage in the #Turkey–#Syria #earthquake towards #Hatay and Syria is not surprising.
More shaking in the first quake was directed towards the south, thus causing the large amount of damage of infrastructure.
(Dark red and red dots indicate generally more shaking) pic.twitter.com/rVLEJis9ce— Risklayer (@risklayer) February 7, 2023
Here is another comparison pre/post-event near #Nurdagi#earthquake #deprem
Also take a look at the collapsed grain silos on the right hand side.
imagery from google-earth and maxar pic.twitter.com/2PHCAKrONR
— Andreas Schäfer (@DrAndreasS) February 9, 2023
Extended coverage of Turkey-Syria Earthquake displacement from pixel tracking with Sentinel-2 imagery. Data at: https://t.co/lZPKL5ZSB9 pic.twitter.com/x12RL1DxGg
— COMET Datasets & Services (@COMET_database) February 9, 2023
Corruption kills.
“This same (BBC Turkish) report cited the Environment and Urbanisation Ministry as stating in 2018 that over 50% of buildings in Turkey – equivalent to almost 13 million buildings – were constructed in violation of regulations.” https://t.co/W5vIm9EniM
— Beth Bartel (@EatTheCrust) February 9, 2023
6.7 meter offset!
Me and @KokumMehmet measured 6.7 m fence offset along the Sürgü-Çardak Fault. #earthquake #TurkeyEarthquake #TurkeyQuake #Elbistan #Kahramanmaras pic.twitter.com/kkhioL5MtV
— Taylan SANÇAR (@tsancar) February 9, 2023
We GSI detected coseismic deformation by the earthquake (M 7.8, M7.5, USGS) occurred in the Republic of Turkey on Feb. 6, 2023 (UTC) with InSAR/Pixel Offset analysis of JAXA ALOS2/PALSAR-2.https://t.co/vEiQJIYrca pic.twitter.com/eb52SSHKh5
— 国土地理院地理地殻活動研究センター (@GSI_Research) February 9, 2023
Here is the EKZ1 GNSS station, which is very close to epicenter of 06.02.2023 Elbistan Earthquake Mw7.6
There is approximately 4 meters coseismic displacement in EKZ1 after the second earthquake.@etayruk @akurt_74 @profugurdogan @AktifTektonik pic.twitter.com/F3HeQiprgZ
— Seda Özarpacı (@sedaozarpaci) February 9, 2023
Turkish Earthquake Scientist Turns Turkey-Syria Earthquake Into Real-Life Lesson for Students | CSUF News @csufcnsm Dr. Sinan Akçiz #TitanGeologyhttps://t.co/nSFqojsZOt
— CSUFullertonGeology (@CSUFGeology) February 9, 2023
My science friends: speed of discovery, research cooperation, data sharing — outstanding
But foremost, I am human, a father of 3, a husband.
I was interview by several Turkish journalists; some crushed while we spoke. 20'000 lives lost – 20'000 … and not over yet … pic.twitter.com/3CG1PNF7qB— Martin Mai (@Prof_QuakeMod) February 9, 2023
Well done, Sentinel-1! Now the ball goes to the unwrapping algorithms: a very high fringe rate, but well shaped. Thanks @CrisTolomei (#INGV GeoSAR Lab) for this first image.#EarthquakeTurkeySyria pic.twitter.com/xd7rRtDQDO
— Simone Atzori (@SimoneAtzori73) February 9, 2023
(2/2) The ALOS-2/PALSAR-2 Data Products are provided by JAXA and analyzed at the NASA Jet Propulsion Laboratory. The area close to epicenter of the Mw 7.8 earthquake moved towards east and up. pic.twitter.com/5Jdo7knHxA
— Advanced Rapid Imaging & Analysis (ARIA) (@aria_hazards) February 9, 2023
More fault crossing profiles north of the epicenter. Data from JAXA by agreement with NASA. #Earthquake #Turkey pic.twitter.com/sLJTMKthEH
— Danielle Lindsay (@DLindsay_EQ) February 9, 2023
#Kahramanmaraş #deprem #earthquake #surfacerupture #yüzeykırığı Hatay Kırıkhan @AynurDikbas DoğacanÖzcan @ProfHasanMandal @TUBITAK_MAM @paleoseismicity @DJIGlobal pic.twitter.com/XVR1qigfnO
— M. Korhan Erturaç (@mkorhanerturac) February 9, 2023
Giving media interviews about geohazard events is fairly simple if you're giving it in an unaffected country. Giving a live interview for the country most impacted is trickier. I just gave a live interview on Turkish TV & here are the #scicomm questions I first considered. pic.twitter.com/bD1keZYgFQ
— Stephen Hicks 🇪🇺 (@seismo_steve) February 7, 2023
UPDATE: 2023.02.12
Today I got caught up with embedding tweets.
The range offset map from Sentinel-1 shows the two ruptures clearly
Data available athttps://t.co/IzMLypaBF7
We should have complete coverage for this terrible event by tomorrow morning. The scale of the event is frightening and our thoughts go out to everyone in the area. pic.twitter.com/lCanGRFAZ4
— NERC COMET (@NERC_COMET) February 9, 2023
The same North-South displacement field with fault trace overlay (from MTA 250K fault maps) 2/2 pic.twitter.com/L7pTLLhIKj
— Sotiris Valkaniotis (@SotisValkan) February 9, 2023
Pixel tracking of the Mw 7.8 earthquake in Turkey using Sentinel-2 optical satellite images shows a very large fault rupture, with at least 250 km of fault motion reaching up to ~5 m.
Download fault traces and offsets here: https://t.co/IJRTggiB2h pic.twitter.com/yzjhx4RGTY
— Dr. Chris Milliner (@Geo_GIF) February 9, 2023
Full extent map. Note that processing is preliminary and the images contain linear artifacts. pic.twitter.com/qZvtIdsx0a
— COMET Datasets & Services (@COMET_database) February 9, 2023
Washington Post article this morning with contributions from @ezgikarasozen, @DrWendyRocks, and me, on the known risk of earthquakes in this region, and the inadequacy of our preparedness not only in Türkiye, but many places around the world. https://t.co/EVYRdqsHka
— Harold Tobin (@Harold_Tobin) February 9, 2023
5.20 m offset along the Surgu-Cardak Fault (February 6th, 2023, 13:23, M7.6). with @tsancar @firatresmihesap @fu_ogrenci @AktifTektonik @paleoseismicity @ProfGoktas @zekiakbiyik #TurkeySyriaEarthquake #earthquake pic.twitter.com/VDa4tE076R
— Mehmet Köküm (@KokumMehmet) February 9, 2023
Newly available Maxar satellite imagery shows several hundred meters long surface rupture with horizontal displacements up to 4m near Nurdağı, Gaziantep province, Turkey. pic.twitter.com/3JVZTTHrk1
— Nahel Belgherze (@WxNB_) February 9, 2023
Gövdesinde çatlaklar yarıklar oluşan ve sızıntı başlayan Malatya'daki Sultansuyu Barajı tahliye ediliyor… Diğer barajlarda çatlaklar olduğu bilgisi var. Bu barajlar çökerse bu su önüne gelen evi canlıyı alır götürür. Umarım önlem alınıyordur alınır!!! #cokusdonemi pic.twitter.com/ypPaxDuRqZ
— Who? (@who98408150) February 8, 2023
Compete picture of the two earthquake ruptures now available from the Sentinel-1 descending pass. @CopernicusEU @COMET_database
Image below is range offsets from pixel tracking. The two ruptures appear not to be connected.
Scale of event is horrific – the image is ~250 km across pic.twitter.com/kc7u3k6z3g— NERC COMET (@NERC_COMET) February 10, 2023
6 Şubat 2023 Mw=7.8 depremi Amik ovasını doğudan sınırlayan ÖDFZ ve batıdan sınırlayan DAFZ (Amanos segmenti) üzerinde birçok segment üzerinde çoklu kırılmaya yol açmıştır. Tıpkı 12 fayda kırılmaya yol açan 14 Kasım 2016 Kaikoura depremi (Y.Zellanda) depremi (Mw=7.8) gibi#deprem pic.twitter.com/STEv8BsfyX
— Dr. Ramazan Demirtaş (@Paleosismolog) February 10, 2023
#Earthquake in #Türkiye 🇹🇷
Impressive image where you can see the horizontal displacement caused by the catastrophic earthquake. Situation before and after in #Nurdağı 25/01 – 09/02, 2023. @CopernicusEU #Sentinel2 🛰️ | h/t @syf_kync @Rainmaker1973 | 🧵1/n pic.twitter.com/sWDff2863i
— Iban Ameztoy (@i_ameztoy) February 10, 2023
Analisi preliminare delle registrazioni accelerometriche del terremoto in Turchia (Mw 7.9) del 6 febbraio 2023 – https://t.co/SyzWQK3xxr
— INGV presidente (@ingv_president) February 10, 2023
800 aftershocks in 4 days (data from @lastquake)#TurkeySyriaEarthquake pic.twitter.com/awlWmnjkKm
— Gilles Mazet-Roux (@gmazet) February 10, 2023
I posted an animation earlier this week about the westward motion of Anatolia (Turkey), pushed by Arabia. That was part of a larger reconstruction, of which this clip shows the last 100 million years (published in Gond. Res., 2020). #TurkeySyriaEarthquake @UUGeo #geology pic.twitter.com/GPUYzyIDvC
— Douwe van Hinsbergen (@vanHinsbergen) February 10, 2023
Next, the range offsets, which record the same deformation as the InSAR, but less sensitively. In this case, that may not be a bad thing, the deformation is large! The range pixel size is 2.3 m, so the largest offsets are around 5.5 m in range. Positive deformation is to the ENE. pic.twitter.com/c7umSsjK0Z
— Dr Gareth Funning (@gfun) February 10, 2023
2/2) Along-track (azimuth) and across-track (range) offset maps showing near-field deformation. Access our disaster response datasets via: https://t.co/WeaE2pihgX pic.twitter.com/Zk0ZM1JjQb
— Advanced Rapid Imaging & Analysis (ARIA) (@aria_hazards) February 10, 2023
NASA and other agencies are using satellites to map damage caused by the 7.8 and 7.5 earthquakes in southern Türkiye and western Syria on Feb. 6. https://t.co/C7jWcow5Gn
— NASA Earth (@NASAEarth) February 10, 2023
Bulunduğu sokaktaki tüm yapılar yıkılırken İnşaat Mühendisleri Odası depremde hiçbir zarar görmedi. (Kahramanmaraş) pic.twitter.com/wKRWVH9Rt8
— Etkili Haber (@etkilihaber) February 10, 2023
M7.8 and M7.5 Turkey earthquakes, as seen from space by radar (ESA Sentinel-1 sensor). To date, satellite images have been over the western half of the ruptures. Sentinel-1 will fly over the eastern half on Feb 10 and hopefully complete the rest of the picture. pic.twitter.com/RR1KhoISnb
— gCent (@gCentBulletin) February 9, 2023
Sentinel-1 descending interferogram and range pixel offsets over the Turkey earthquake. Epicentres shown by red stars pic.twitter.com/3qejCsJMaP
— COMET Datasets & Services (@COMET_database) February 10, 2023
Here is also the range offset map of des21 track. The fault triple junction is digitized almost exactly along the discontinuity. https://t.co/wjGYc0zKer pic.twitter.com/nmgFKMQljJ
— Zeyu Jin (@jzyjzy9) February 10, 2023
Surface displacement maps for the tragic M7.8 and M7.5 earthquakes in southern Turkey. There were several metres of slip which can be traced ~300 km on one fault and ~100 km on the second.
Calculated from Sentinel-2, I have uploaded the data for sharing: https://t.co/WayeuyMlUw pic.twitter.com/J6dzPVA08B
— Max Van Wyk de Vries (@Max_VWDV) February 9, 2023
Yıl 1996: Türkiye'de M>7.0 #deprem üretme potansiyeli yüksek 15 SİSMİK BOŞLUK olan fayları belirlemiştik. Bu boşluklardan 24 Ocak 2020 ve 6 Şubat 2023 depremler olmak üzere 7'si büyük deprem üretti (Demirtaş ve Yılmaz 1996).https://t.co/ABPIm7FpFVhttps://t.co/gOKV5Uw3A6 pic.twitter.com/3RpxDzWAbv
— Dr. Ramazan Demirtaş (@Paleosismolog) February 10, 2023
Rupture processes of the two Turkey major events. The M7.8 mainshck first ruptured NE direction for over 100km, then departed from hypocenter to the SW. The M7.6 event ruptured bilaterally, and its last subevent E4 activated a NE-trending subfault. Very complex ruptures. pic.twitter.com/5HFVbA9CSx
— Zhe Jia (@jiazhe868) February 10, 2023
NASA-NOAA's Suomi NPP satellite captured the power outages resulting from the massive 7.8 earthquake that struck southern Turkey and Syria. Look at all these cities plunged into darkness along the East Anatolian Fault Zone. pic.twitter.com/ubHpdmMwLe
— Nahel Belgherze (@WxNB_) February 10, 2023
The azimuth offsets, positive to the SSW, once again highlight the slip along the East Anatolian fault and are somewhat insensitive to the northern fault (which can be made out from the E-W trend of the later aftershocks, shown in black). pic.twitter.com/e1KZmpUM45
— Dr Gareth Funning (@gfun) February 10, 2023
This across-fault profile over the Mw 7.5 rupture and near its epicenter shows an offset of over 8 m. Red line is from result shown above, green is from @Max_VWDV. Location is Lat: 38.02, Long: 37.21. Note y-axis ranges from -4 to 4 m. pic.twitter.com/AfUCrPmUrF
— Dr. Chris Milliner (@Geo_GIF) February 10, 2023
Mr. Milliner, this video clearly shows the devastating surface movement during the first EQ that hit our country. pic.twitter.com/qVMwH1r2iJ
— UzAy&Dünya (@UzaydaBugun) February 10, 2023
With the last two large events on this fault segment occurring in 1509 and 1766, and a suggested recurrence interval of ~200-250 years, this part of the fault may produce an earthquake at any time.
— Dr. Judith Hubbard (@JudithGeology) February 10, 2023
On the Blog: Radar interferogram over Turkey & Syria using @CopernicusEU Sentinel-1 acquisitions of 9 Feb. & 28 Jan. 2023
+ link to the public data package (products generated with InSAR processor from @CNES & @TRE_ALTAMIRA hosted on GEP)https://t.co/gVnIR9mrHt
— Geohazards Exploitation Platform (@esa_gep) February 10, 2023
We've updated the report on the #earthquake #engineering aspects of the #Turkey #seismic sequence to V2.0. This versionis based on recently released data and also makes them available -> https://t.co/ImltvfnFjg@ConsorzioReLUIS @UninaIT @IussPavia @UniRCMedi pic.twitter.com/r0RrnNcckD
— iunio iervolino (@iuniervo) February 10, 2023
Here's the animation of the backprojection pic.twitter.com/63hePMCWRZ
— Claudio Satriano (@claudiodsf) February 10, 2023
Deprem bölgesinden bir bina komple temelden kalkmış… Uzmanı değilim ama bilenler yazsın, 5 kat binaya 1-2 metrelik temel atılması neredeyse cinayete teşebbüs değil mi?!pic.twitter.com/XWb6SWcS4k
— can gurses (@canitti) February 9, 2023
Short video that show obvious surface rupture along the Surgu-Cardak Fault with @tsancar @fu_ogrenci @ProfGoktas @AktifTektonik @paleoseismicity @firatresmihesap pic.twitter.com/I2uhEWVSVY
— Mehmet Köküm (@KokumMehmet) February 10, 2023
#surfacerupture #yüzeykırığı #deprem #earthquake #Kahramanmaraş #Hatay #KIRIKHAN @AynurDikbas DoğacanÖzcan pic.twitter.com/p6Um1Dgk0D
— M. Korhan Erturaç (@mkorhanerturac) February 10, 2023
Satellite mapping of earthquake faults has become a powerful tool, especially in the era of @CopernicusEU #Sentinel1a. (#Sentinel1c cannot get up quick enough!) Smart work here from @NERC_COMET – a UK institution making good use of an EU resource! https://t.co/6wRnempIvA pic.twitter.com/NZP0l8FvqF
— Jonathan Amos (@BBCAmos) February 10, 2023
The worst seismic event of 20st century in Turkey, 1939 #Erzincan #earthquake, happened on North Anatolian Fault. Its magnitude (M~7.8-7.9) and rupture length (~350km) compare well with the Mw7.8 of past Monday on East Anatolian Fault, the other major fault of the system. 1/n pic.twitter.com/7r2mRH3Zrc
— Robin Lacassin – @RobinLacassin@qoto.org (@RLacassin) February 10, 2023
Expanded coverage of Turkey earthquake displacement from pixel tracking on Sentinel-2 imagery. Data are noisy around topography. Data including KMZs for Google Earth overlay are at: https://t.co/RFsxdPZeEr pic.twitter.com/t6dC8of86L
— COMET Datasets & Services (@COMET_database) February 10, 2023
Many factors contributed to making this event so deadly. Some were foreseeable, others bad luck. What can we do to mitigate the impacts of the next earthquake?
Something I wrote for the Anadolu News Agency in Turkey.https://t.co/RziBaPgd3C
— Dr. Judith Hubbard (@JudithGeology) February 10, 2023
Journalists: don't. stop. talking. about. Syria. The silence around my country is deafening, it has been for the last few years. People were living in the most dire of circumstances even before the earthquake.
— Rachelle Bonja (@rachellebonja) February 9, 2023
“…although the earthquakes themselves were natural, the devastation is in part man-made.”
In other words, there are no natural disasters. There are natural hazards that occur near human cities and towns that are vulnerable to those hazards, thus creating disasters. https://t.co/6wnnoQvVR8
— Wendy Bohon, PhD 🌏 (@DrWendyRocks) February 10, 2023
Now that we have a quite complete vision of the offsets by satellite imagery, the performance of the fast automated slipmaps can be appraised. Slipmaps from single plane SLIPNEAR method were obtained and published the day of the earthquakes. Here compared to offsets by COMET (1) pic.twitter.com/pBUVC1Jz1y
— Bertrand Delouis (@BertrandDelouis) February 10, 2023
Geodetic slip model for the Turkey earthquake, which combines both M7.8 and M7.5 events. Data are Sentinel-1 range offsets from ascending 14 and descending 21 tracks. The estimated geodetic slip moment is 7.9872. pic.twitter.com/iKIJKBZ96H
— Zeyu Jin (@jzyjzy9) February 11, 2023
#EMSR648 #Earthquake in #Türkiye🇹🇷
Our #RapidMappingTeam has delivered its Grading Monitoring Product for the #Kahramanmaraş AoI using VHR 🛰️ imagery
9⃣2⃣7⃣ affected buildings🏚️ have been detected:
🔴286 destroyed
🟠185 damaged
🟡456 possibly damaged🔗https://t.co/Rxfhj84v3R pic.twitter.com/miPkl6QGFL
— Copernicus EMS (@CopernicusEMS) February 10, 2023
The earth is going to quake, and we need to build the things around us accordingly. Enforcement of modern building regulations will save lives when major earthquakes strike. pic.twitter.com/dmKrcjeXX7
— Adam Pascale (@SeisLOLogist) February 10, 2023
Ölü Deniz Fayı Narlı Segmenti üzerinde gelişmiş olan yüzey kırıklarını ilişkin MTA tarafindan bulunan ilk bulgular#atag #deprem #jeoloji pic.twitter.com/etLIf4JYR9
— Hasan Elmacı (@arduvaz06) February 10, 2023
Earthquake prediction has been called, by people including me, the holy grail of seismology.
In fact the holy grail is more prosaic, and more attainable: understanding how the ground will shake in future earthquakes so buildings and infrastructure can be built appropriately
A 🧵— Dr. Susan Hough 🦖 (@SeismoSue) February 11, 2023
California faces threat from the type of back-to-back mega-earthquakes that devastated Turkey https://t.co/2yTmFpmkmQ
— Ron Lin (@ronlin) February 8, 2023
This is, and it even has a section for non engineers. https://t.co/MbLXOvZZBW https://t.co/AiSz0PJKYQ
— Forrest Lanning (@rabidmarmot) February 11, 2023
California hasn't seen a catastrophic earthquake recently. But ‘quiet’ period won’t last
“We’ve had 7.8 earthquakes in our historic past. We’ve had a great run without them, but it’s important to be prepared for these possibilities in the future.” https://t.co/of46rmi1h1
— Ron Lin (@ronlin) February 7, 2023
1-Bu Türkiye'nin gördüğü en büyük ivmeli depremi değerli arkadaşlar. Üstelik tek bir noktada değil, kırık boyunca çok yüksek değerler. Düşünün ki 200mG değerleri bile hasar vermek için yeterli iken, bu depremde hemen her yerde 400mG'nin üzerinde. #deprem #hatay #Turkey #MARAS pic.twitter.com/ikf4qyQiWh
— Eşref Yalçınkaya (@eyalcinka) February 11, 2023
We have just published a 🆕 Information Bulletin!
It details #CEMS activities related to the damage assessments performed in the aftermath of the disastrous #earthquake that struck #Türkiye 🇹🇷 on 6 February
5⃣3⃣ maps delivered in ~100h
More👉 https://t.co/hAVwDgCV2G pic.twitter.com/9478AmUwEP
— Copernicus EMS (@CopernicusEMS) February 10, 2023
Additionally, as @DrLucyJones has said, knowing that people are working on the science behind the event can sometimes be comforting to those experiencing it, because it can help them feel like the cause is less out of control if it is known and understood.
— Wendy Bohon, PhD 🌏 (@DrWendyRocks) February 11, 2023
❝24 saatten kısa bir süre içinde bu kadar büyük iki deprem neredeyse eşi benzeri görülmemiş bir olay❞
ABD’li sismolog Tobin, Kahramanmaraş merkezli, 10 ili etkileyen depremlerin büyüklüğünü ve yapısını AA’ya anlattı https://t.co/zkDmUmjXXO pic.twitter.com/AUO4d3Y2KC
— ANADOLU AJANSI (@anadoluajansi) February 9, 2023
Why the Earthquake in Turkey Was So Damaging and Deadly – Scientific American https://t.co/GY4xH9dFhs
— M. Teresa Ramírez-H. (@TeresaRamirezH) February 11, 2023
Bulevar Azerbaycan esquina con Bulevar Hükümet 2022/2023 #GoogleMaps
Ciudad de #Kahramanmaraş, #Turquia. 🇹🇷 pic.twitter.com/7CcBev4vlC
— Alejandro S. Méndez ⚒️ (@asalmendez) February 11, 2023
Kandilli's Disaster Preparedness Education Unit used to have a great handbook/resource on this but it looks like it's no longer available https://t.co/NXsKzPiqRE
— elizabeth (@kitabet@zirk.us) (@kitabet) February 11, 2023
ARIA Displacement maps from Copernicus Sentinel-1 track D21 acquired on 10 Feb. 2023 for Türkiye (Turkey) earthquakes are now released. Along-track and across-track displacement maps cover full length of both magnitude 7.8 and 7.5 quake ruptures. Online: https://t.co/1W1sMtatQd pic.twitter.com/Fj4Q0CTjEQ
— Advanced Rapid Imaging & Analysis (ARIA) (@aria_hazards) February 12, 2023
Türkoğlu’nda 6 Şubat #deprem inin yüzey kırığı / Surface rupture of the 6 Faburary Mw 7.8 Kahramanmaraş #Earthquake at Türkoğlu @AktifTektonik @akyuz24 @HNK390978941 @KirkanErdem @asensabuncu Gursel Sunal, Nurettin Yakupoglu pic.twitter.com/CocbSjNKUm
— Cengiz Zabcı (@CengizZabci) February 11, 2023
Yeşilyurt köyü/Islahiye zeytin bahçesinde meydana gelen sol yanal ötelenme./ Sinistral offset that take place in an olive garden at Yeşilyurt village,İslahiye#Gaziantep #Islahiye #deprem #earthquake #Türkiye #surfacerupture #leftlateral pic.twitter.com/Yi96WASpeM
— OzdemirAlpay (@geodesist_a) February 11, 2023
Böyle bir deprem bekleniyor muydu? #AçıkveNetDepremÖzel'de @kubrapc sordu; Prof. Dr. Ziyadin Çakır yanıtladı: "Böyle bir deprem bekleniyordu. Fakat yıkımların büyük kısmı binaların depreme dayanıklı olmamasından kaynaklanıyor. Zeminler de uygun değildi." pic.twitter.com/e1pgBB2KK4
— Habertürk TV (@HaberturkTV) February 6, 2023
To try this for yourself, click the link below, wait for it a sec, then click & drag the slider right & left. You’ll see cities lit up at night before (more lights on) [left side] the earthquakes and after (darker due to power outages) [right side]. Black Marble via @NASAEarth 🛰️ pic.twitter.com/RF0hnirlCI
— Ken Hudnut 🌎 (@HudnutKen) February 11, 2023
#Hatay’ın Altınözü ilçesinde deprem sonrası tarlada 30 metre derinliğinde yarık meydana geldi.
IG: asayisberkemal34_ pic.twitter.com/1Iot7OZdyR— 🗨️ Haber Seyret (@haberseyret) February 11, 2023
ARIA Damage Proxy Map (DPM) calculated from Copernicus Sentinel-1 track 21 (10 Feb. 2023) shows likely damage in many cities and some other surface changes that could be snow cover, flooding, or liquefaction. Data online at https://t.co/tRn9fvUmQM pic.twitter.com/hWdAtVBv9D
— Advanced Rapid Imaging & Analysis (ARIA) (@aria_hazards) February 12, 2023
Sentinel-1 Ascending T14 POT Results
Code: https://t.co/X8UKYgT6Bq
Data:https://t.co/nPnPdi8Dsl (use in your own risk)
(just want to present something when you improved a 10hours-process to 10mins) pic.twitter.com/9BURDRzc00— Yunmeng Cao (@yunmengCao) February 12, 2023
Security camera footage of the ground shaking in Maras. @mrbrianolson https://t.co/EU9fy8BqJi #gazetesozcu via @gazetesozcu
— Sinan Akciz (@snnkcz) February 11, 2023
#Sentinel-1 Ascending interferogram/LOS, Slant range pixel offsets displacement maps, and 3D displacement view (exaggerated) of the 06.02.2023 #Kahramanmaras #TurkeySyriaEarthquake . #InSAR data obtained from @NERC_COMET
/ @COMET_database @caglayanayse @ISIK_VEYSEL pic.twitter.com/PGWAz5eTMY— Reza Saber (@Geo_Reza) February 10, 2023
TÜBİTAK 1002-C projesi kapsamında Prof. Dr. Semih Ergintav’ın yürütücü olduğu @YildizEdu @itu1773 ve @Kandilli_info’nin birlikte yaptıkları çalışmada arazide GNSS ölçümleri yapılacak noktaların kontrolleri devam etmektedir. @ProfHasanMandal @profugurdogan @ziyadin @sergintav pic.twitter.com/A4EieKcjto
— OzdemirAlpay (@geodesist_a) February 11, 2023
Wow! "30-meter-deep rift formed" after the #earthquake in #Türkiye | You can see the before/after situation between the 25th of January and 9th of February 2023. h/t @Rainmaker1973 pic.twitter.com/kjmfkSqZY9
— Iban Ameztoy (@i_ameztoy) February 11, 2023
A joint EERI-GEER advance reconnaissance team will join colleagues in the field in Turkey early next week. For more information about EERI's response to the Turkey/Syria earthquake, view the news post here: https://t.co/5uDyE6CJkj
— EERI (@EERI_tweets) February 11, 2023
Unfortunately the Turkish media interviewed many seismologists, not to learn from them but to reinforce the narrative that "the earthquake was too big to handle", despite the fact that the experts also underlined the negligence in applying the earthquake regulations. Shameful. pic.twitter.com/7BnGvg1jni
— Tugrulcan Elmas (T.j.) (@tugrulcanelmas) February 11, 2023
Approximate 3-meter shift in Hatay from Maxar satellite image. #earthquaketurkey #Geology #Türkiye 🇹🇷 pic.twitter.com/OGNBZAJM6b
— Abdülhamit Doğanay (@abdulhamid_hoca) February 12, 2023
Here is the latest mapping status and priority for the #OpenStreetMap #TurkeySyriaEarthquake response. Urgent projects: 14226, 14232, 14235, 14245, 14246.
Urgent projects in Syria have so far received less mapping and can use your attention! pic.twitter.com/K4Tulax2Bj
— Humanitarian OpenStreetMap Team (@hotosm) February 12, 2023
Coseismic displacements near the two faults are asymmetric, in part due to opposing motion between the two faults. This prelim. result is from Sentinel-1&2 offsets by @JinhongLiu4 here at #KAUST as a part of the CDI and @CES_KAUST group efforts. @KAUST_PSE @ESA_EO 1/5 pic.twitter.com/2fMdCWbSos
— Sigurjón (Sjonni) Jónsson (@Sjonni_KAUST) February 12, 2023
YOL YERLE BİR OLDU
Adıyaman-Şanlıurfa-Gaziantep Otoyolu'nun üzerinden geçen Köşeli köyünün yolunun yerle bir olması ve oluşan devasa çatlaklar depremin büyüklüğünü bir kez daha gösterdi. pic.twitter.com/BLu2ADfTLE
— Sabah (@sabah) February 12, 2023
10-11 Şubat saha çalışmalarını incelemek için; https://t.co/MMrzZTgvDm pic.twitter.com/k7rP283a56
— MTA Genel Müdürlüğü (@MTAGenelMd) February 12, 2023
Initial images from the major Turkey-Syria earthquakes this week show #landslide damage to 🛣️ roadways, writes @davepetley in The Landslide Blog. #AGUblogshttps://t.co/aImRbESyzi
— AGU (American Geophysical Union) (@theAGU) February 12, 2023
İlk andan itibaren Van YYÜ ve Alperen ekibi olarak bölgeye vardık, tabi ilk amaç afetzede olduğu için yolda yüzey kırığı ile ilgili çok kısa gözlem yapabildik.Ötelenme yaklaşık 3.5 metre. Anca paylasabildim @saglamselcuk @M_t_h_n_O_z_d_g @vanlinihathoca #depremzede #kahramamaras pic.twitter.com/sho0AqroRb
— sacit mutlu (@sacitmutlu65) February 12, 2023
UPDATE 13 February 2023
Preliminary mapping of fault rupture in Turkey earthquakes. Red lines are simplified fault traces based on radar images. Blue lines are detailed surface rupture mapped from high-res satellite imagery. Will be updated as more data become available. https://t.co/X5qaQwlbud pic.twitter.com/dEohrosSdP
— USGS Earthquakes (@USGS_Quakes) February 13, 2023
Rupture (!) velocity of second sub-event of M7.8 earthquake. It looks equal to the S wave velocity. May be causing high amplitudes to the SW.@ALomaxNet #seismology #earthquaketurkey @AGUSeismology @EGU_Seismo @ntv @halktvcomtr @HaberturkTV @FOXhaber pic.twitter.com/eRnhU0cuP7
— Eşref Yalçınkaya (@eyalcinka) February 13, 2023
House on a fault! Result is not surprising. @firatresmihesap @fu_muh_1967 @AktifTektonik @paleoseismicity #earthquakeinturkey #earthquake @tsancar pic.twitter.com/rwnfBm3165
— Mehmet Köküm (@KokumMehmet) February 13, 2023
Map of the seismic activity of February 6, 2023, near the Turkey –Syria border. Picture from @Prof_QuakeMod (CES Group) and @Sjonni_KAUST (CDI Group) professors of Earth Science and Engineering Program.
Read the full article here – https://t.co/EAWFPSVyMV pic.twitter.com/VtcMzgcFEg
— KAUST Earth Science and Engineering Program (ErSE) (@KAUST_ErSE) February 13, 2023
#CCMEO’s EGS team used #RADARSAT-2 imagery to assess displacement as a result of the #earthquake in Turkey and Syria. The map shows more than 3m displacement along the fault line. https://t.co/abvBZLhOkz. Follow @csa_asc and @DisastersChart for updates. pic.twitter.com/6gq218aTOt
— Eric Loubier (@LoubierEric) February 10, 2023
Well-constrained locations of the 2800+ aftershocks computed by @DepremDairesi. They delinate a complex faults system.#turkeyearthquake pic.twitter.com/YD3m3Dclsu
— Gilles Mazet-Roux (@gmazet) February 13, 2023
An interferogram showing the coseismic surface displacement in the area near #Gaziantep, generated from multiple @CopernicusEU #Sentinel1 scans – before & after the Türkiye–Syria earthquakes.
It reveals a large-scale deformation between Maras and Antakya: https://t.co/7fU1Zy6b6j pic.twitter.com/IoEefwvNYS— ESA EarthObservation (@ESA_EO) February 13, 2023
On the Blog: Measuring horizontal ground deformations of the Turkey-Syria earthquakes with @CopernicusEU Sentinel-2 images from Jan 25 (pre-) & Feb 9 (post-) 2023
Products generated on GEP by CNRS/EOST & ESA/SAT using the @ForMaTerre service GDM-OPT-ETQhttps://t.co/YaUhK4gFDv
— Geohazards Exploitation Platform (@esa_gep) February 13, 2023
My first slip model of the #TurkeySyriaEarthquakes, from #Sentinel1 range and azimuth offsets. It is very preliminary, and needs considerable refinement. Slip is higher on the northern fault, as other models and data have shown. Dips/rakes from the @USGS_Quakes W-phase solution. pic.twitter.com/jucjdbqcyo
— Dr Gareth Funning (@gfun) February 13, 2023
— Harold Tobin (@Harold_Tobin) February 13, 2023
Building codes need to be enforced and know they don’t address existing buildings, which makes up most cities. #retrofit #earthquake pic.twitter.com/AhWCRGSs2T
— Forrest Lanning (@rabidmarmot) February 13, 2023
With help from Prof. Ugur Sanli, #gnss data has been obtained from some @tusaga_actif network stations near the epicenters of the recent #TurkeySyriaEarthquakes. Solutions are available at https://t.co/dHMpWbkpQV. Coseismic displacements from 5 minute samples shown below. pic.twitter.com/ckBf9hzLx7
— Nevada Geodetic Laboratory (@NVGeodeticLab) February 13, 2023
We are moving from Türkoğlu towards Gölbaşı. Offset amount is increasing. S of Kahramanmaraş, nearly 5 m offset. @AktifTektonik @CengizZabci @gulsen_ucarkus @ersenma @KirkanErdem @HNK390978941 @asensabuncu Gursel Sunal, Nurettin Yakupoglu pic.twitter.com/FclrVPPrMS
— H. Serdar Akyüz (@akyuz24) February 12, 2023
This is crazy! 🤯 We used @ASFHyP3 and AutoRIFT, the ITS_LIVE glacier tracking software, to map the displacement from the #turkeyearthquake with incredible fidelity.
Graphic by Alex Gardner, @NASAJPL pic.twitter.com/iLhhk8s6r3
— Joseph H. Kennedy (@aJollyAdventure) February 11, 2023
Also, below are the peak ground accelerations (PGAs) measured from all available stations in Antakya during each of these three earthquakes.
Both spectral and PGAs are above design and maximum considered earthquake levels during the first quake. pic.twitter.com/dPETA8MmWW
— Osman E. Ozbulut (@OsmanEOzbulut) February 13, 2023
Saha incelemelerimiz devam etmektedir. 12-13 Şubat saha çalışmalarını incelemek için; https://t.co/MMrzZTgvDm pic.twitter.com/pXHQTzgqDd
— MTA Genel Müdürlüğü (@MTAGenelMd) February 13, 2023
UPDATE: 14 February 2023
The @Fault2SHA #POQER group is created for organizing further post-#earthquake response in Euro-Med region.
The goal is to promote international cooperation & achieve homogenized geological datasets useful to the Earth Sci and Seismic hazard communities.https://t.co/XF8yMiYtk0— Stéphane Baize (@Stef_EQ_Geology) February 14, 2023
Fault scarp on the East Anatolian Fault.@tsancar @firatresmihesap @fu_muh_1967 @AktifTektonik @paleoseismicity #EarthquakeTurkeySyria pic.twitter.com/nB9P30jtzG
— Mehmet Köküm (@KokumMehmet) February 14, 2023
The 11-year-old Syrian girl Lina and her mother were rescued after spending 160 hours under the rubble. Turkish rescuers worked 10 hours until they were able to reach them. #earthquakeinturkey #earthquakeinsyria pic.twitter.com/t83GCQavUd
— Bana Alabed (@AlabedBana) February 14, 2023
Preliminary mapping of fault rupture in #Türkiye earthquakes updated 13 February 2023. Red lines are simplified fault traces based on satellite radar data. Blue lines are detailed surface rupture mapped from high-res satellite images. https://t.co/X5qaQwlbud pic.twitter.com/BvQF2jzPvU
— USGS Earthquakes (@USGS_Quakes) February 14, 2023
Coulomb stress change for #Turkeyquake using new finite fault model results from @USGS_Quakes. Stress change from all FFM slip resolved onto M7.5 sections (from FFM) receivers. As in earlier results, only the section where M7.5 nucleated has positive change. pic.twitter.com/1LIJxp6kv9
— Michael Bunds (@cataclasite) February 15, 2023
Satellite data show how close the Mw 6.8 that occurred back in 2020 (orange-purple colors) was with the recent Mw 7.8 and Mw 7.5 (red-blue) in Turkey. Only a ~55 km gap exists along the same fault between them. Was this unexpected?
N.B. difference in scale and disp. (1/n) 🧵 pic.twitter.com/NWCIYZZsK5
— Dr. Chris Milliner (@Geo_GIF) February 15, 2023
Updated finite fault models for #Türkiye M7.8 & M7.5 EQs now constrained by seismic & geodetic data https://t.co/hCAE6wtjtm, https://t.co/CK9bX6wo10. Fault geometries from surface rupture mapping of satellite images & radar pixel tracking.
More on FFMs: https://t.co/iPjLVbzyZt pic.twitter.com/ZRq8k30a4s— USGS Earthquakes (@USGS_Quakes) February 14, 2023
UPDATE 23 May 2023
The National Earthquake Information Center rapidly characterized the devastating EQs in Tükiye on Feb. 6 in collaboration w/ Turkish colleagues. Here, we describe how these results came to be, including finite fault models, PAGER, and remote fault mapping: https://t.co/MSVcvsMn9s pic.twitter.com/lH26JQKyrH
— USGS Earthquakes (@USGS_Quakes) May 23, 2023
Aftershocks continue in Turkey – and with them, speculation about possible triggered earthquakes. Most aftershocks are near Göksun – at the western end of the northern rupture. With them come rumors of a possible quake reaching towards Adana.
— Dr. Judith Hubbard (@JudithGeology) May 24, 2023
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References:
Basic & General References
Specific References
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I don’t always have the time to write a proper Earthquake Report. However, I prepare interpretive posters for these events. https://earthquake.usgs.gov/earthquakes/eventpage/us6000i5rd/executive 20220727_philippines_interpretation.pdf 16 MB pdf #EarthquakeReport for M7.1 #Lindol #Earthquake in the #Philippines Shaking reported up to MMI 9! See more abt regional tectonics herehttps://t.co/kZy1TFpDgN USGS page herehttps://t.co/GI4mzfeu0Y pic.twitter.com/pzMzWJDmxm — Jason "Jay" R. Patton (@patton_cascadia) July 27, 2022 There was a magnitude M 6.2 Gempa or Earthquake on 25 February 2022. https://earthquake.usgs.gov/earthquakes/eventpage/us6000gzyg/executive The plate boundary fault system that dominates the tectonics of the Island of Sumatera, Indonesia, is the complicated. The oceanic India-Australia plate converges with the Eurasia plate to form the Sunda trench. This convergent plate boundary forms a subduction zone where the oceanic plate subducts beneath the continental plate. However, the direction of plate convergence is not perpendicular to the plate boundary fault (the megathrust subduction zone). Why does this matter? The amount of plate convergence that is perpendicular to the plate boundary is accommodated by earthquake fault slip on the megathrust. The amount of plate convergence that is parallel to the plate boundary is accommodated by earthquake fault slip on a different series of faults that we call sliver faults. The Great Sumatra fault is one of these [forearc] sliver faults. Here is a figure from Lange et al. (2008) that shows how oblique plate convergence forms both a subduction zone and a forearc sliver fault system. The M 6.2 earthquake is a strike-slip earthquake along the Great Sumatra fault, one of these forearc sliver faults. Based on our knowledge of this fault system and the earthquake mechanism, we can easily interpret this to be a right-lateral strike-slip fault. There are numerous historical analogies from the past century. Most of the events in the past few decades have been in the M 6-7 range, though there have been events of larger magnitude in the past centuries.
India-Australia plate subducts northeastwardly beneath the Sunda plate (part of Eurasia) at modern rates (GPS velocities are based on regional modeling of Bock et al, 2003 as plotted in Subarya et al., 2006). Historic earthquake ruptures (Bilham, 2005; Malik et al., 2011) are plotted in orange. 2004 earthquake and 2005 earthquake 5 meter slip contours are plotted in orange and green respectively (Chlieh et al., 2007, 2008). Bengal and Nicobar fans cover structures of the India-Australia plate in the northern part of the map. RR0705 cores are plotted as light blue. SRTM bathymetry and topography is in shaded relief and colored vs. depth/elevation (Smith and Sandwell, 1997).
This movie illustrates simulation of seismic wave propagation generated by Dec. 26 Sumatra earthquake. Colors indicate amplitude of vertical displacement at the surface of the Earth. Red is upward and blue is downward. Total duration of this simulation is 20 minutes. Source model we used is that of Chen Ji of Caltech. Simulation was performed by using the Earth Simulator of JAMSTEC.
Map of Southeast Asia showing recent and selected historical ruptures of the Sunda megathrust. Black lines with sense of motion are major plate-bounding faults, and gray lines are seafloor fracture zones. Motions of Australian and Indian plates relative to Sunda plate are from the MORVEL-1 global model [DeMets et al., 2010]. The fore-arc sliver between the Sunda megathrust and the strike-slip Sumatran Fault becomes the Burma microplate farther north, but this long, thin strip of crust does not necessarily all behave as a rigid block. Sim = Simeulue, Ni = Nias, Bt = Batu Islands, and Eng = Enggano. Brown rectangle centered at 2°S, 99°E delineates the area of Figure 3, highlighting the Mentawai Islands. Figure adapted from Meltzner et al. [2012] with rupture areas and magnitudes from Briggs et al. [2006], Konca et al. [2008], Meltzner et al. [2010], Hill et al. [2012], and references therein.
New revised (simplified) active fault map of the Sumatran Fault Zone (SFZ) according to the PuSGeN Team for Updating Indonesia Seismic Hazard Map (2016) with new slip rates from geological and geodetical (GPS) recent studies.
Map of 20 geometrically defined segments of the Sumatran fault system and their spatial relationships to active volcanoes, major graben, and lakes.
Tectonic modelling based on continuous GPS – SuGAr 9 Sumatran GPS Array) and coral uplift rates,
Comparison of GPS velocity profiles across the Sumatran fore arc inferred from (left) kinematic block models (right) with previously published velocity profiles. Modeling all fore-arc site velocities with a single strike-slip fault results in anomalously high inferred slip-rates (>22mm/yr) and missing the Sumatran Fault trace by up to 40km. Incorporating the effect of oblique locking of the Sunda megathrust results in lower inferred slip – rates for the Sumatran Fault (~15mm/yr) that are more consistent with updated geological slip rates.
A plausible (but nonunique) history of deformation along the obliquely convergent Sumatran plate margin, based upon our work and consistent with GPS results and the timing of deformation in the forearc region. (a) By about 4 Ma, the outer-arc ridge has formed. The former deformation front and the Mentawai homocline provide a set of reference features for assessing later deformations. From 4 to 2 Ma, partitioning of oblique plate convergence occurs only north of the equator. Dextral-slip faults on the northeast flank of the forearc sliver plate parallel the trench in northern Sumatra but swing south and disarticulate the forearc basin and outer-arc ridge north of the equator. (b) Slip partitioning begins south of the equator about 2 Ma, with the creation of the Mentawai and Sumatran faults. Transtension continues in the forearc north of the equator. (c) In perhaps just the past 100 yr, the Mentawai fault has become inactive, and the rate of slip on the Sumatran fault north of 2°N has more than doubled. This difference in slip rate may be accommodated by a new zone of transtension between the Sumatran fault and the deformation front in the forearc and outer-arc regions.
Relocated MJHD epicenters. (a) Northern Sumatra. (b) Central Sumatra. (c) Southern Sumatra. Solid lines with names indicate segments of the Sumatran fault (Sieh and Natawidjaja, 2000). Symbols are as in Figure 2. The thick solid line (see Fig. 4c) indicates the Ranau–Suwoh area, which was severely damaged by the 1933 Liwa earthquake (Berlage, 1934;Widiwijayanti et al., 1996). The slip rates of the Sumatran fault in northern, central, and southern Sumatra are taken from Ito et al. (2012) and Genrich et al. (2000) for Global Positioning System (GPS) and Bellier and Sebrier (1995) for Satellite Pour l’Observation de la Terre (SPOT).
Earthquake history along the Sumatran fault since 1892. Fault planes estimated in this study are shown by thick lines. SG: Seismic gap.
Coulomb stress models resolved on receiver faults of central part of GSF from coseismic slip model of each large interplate earthquakes. The color represents the maximum stress changes at 10 km depth with a scale saturated at 1 bar.
Cumulative ΔCFF of each earthquake listed in Table 1 (a) and cumulative ΔCFF of 1797, 1833, and 1861 earthquakes (b). The cyan ellipses are the damage area of large intraplate earthquakes marked as green star. The ΔCFF is calculated at 10 km depth with a scale saturated at 1 bar.
FOS = Resisting Force / Driving Force
Annual probability of experiencing a tsunami with a height at the coast of (a) 0.5m (a tsunami warning) and (b) 3m (a major tsunami warning).
#EarthquakeReport for M 6.2 #Gempa #Earthquake along the #Sumatra fault just north of #Padang evidence for strong ground shaking and possible surface rupture read more herehttps://t.co/xujTF3MERq pic.twitter.com/tWEhQTCj06 — Jason "Jay" R. Patton (@patton_cascadia) February 27, 2022 A Mw6.2 earthquake just occurred along the Sumatran Fault in Indonesia. This fault extends for >1700 km, slicing Sumatra in two. The fault aligns closely with the volcanoes generated by the subduction zone to the west. See the fault & volcanoes in the topography below! 🧵 1/ https://t.co/rY6yzEwBwG pic.twitter.com/5gd5YjaPfG — Dr. Judith Hubbard (@JudithGeology) February 25, 2022 Kondisi saat ini di Kec. Talamau Pasaman Barat. Bagi manteman yang ada dilokasi boleh mention kondisi di sana ya @infomitigasi @JogjaUpdate pic.twitter.com/910vTLMioM — Podcast Asap_id (@podcastasap_id) February 25, 2022 An earthquake with Mw 6.2 struck inland with dextral mechanism in the segmentation of Sumatra Fault on this morning (Indonesia Time), killing at least two people and causing tremors that were felt until Singapore and Malaysia. pic.twitter.com/Gd8MoXC8u4 — andrean (@andreanjtk) February 25, 2022 Rangkaian #Gempa yang terjadi di #Sumbar, tapatnya di #Pasamanbarat pada 25 Feb 2022. Rangkaian gempa ini diawal oleh gempa pembuka (foreshock) M=5,2 (08:35:51 WIB), berselang 3 menit 42 detik diikuti oleh gempa utama M=6,2 (08:39:29 WIB). pic.twitter.com/iNQL9tiIcZ — Zulfakriza Z. (@zulfakriza) February 25, 2022 Akibat Gempa di Pasbar terjadi juga longsor di Malampah Pasaman pic.twitter.com/WU9MJ7pSFm — Yazid Lubis (@YazidLubis9) February 25, 2022 Did you feel shaking from this morning's #Sumatra earthquake? The rupture occured along a segment of the Sumatran Fault. While the segment is 400km away from #Singapore, it was widely felt across the island. Learn more about today's event in our blog post https://t.co/bY8KDv3GAx — Earth Observatory SG (@EOS_SG) February 25, 2022 6.1 Mw North-Central Sumatra (#INDONESIA 🇮🇩), a right-lateral strike-slip "Southern Angkola Segment" (Great Sumatran Fault System), potentially for a >7.5 Mw. pic.twitter.com/YSXqgH1Ge1 — Abel Seism🌏Sánchez (@EQuake_Analysis) February 25, 2022 Some hours ago, strong shallow M6.2 #earthquake in Sumatra, widely felt also in Malaysia and Singapore. — José R. Ribeiro (@JoseRodRibeiro) February 25, 2022 Di dekat episenter gempa Pasaman Mag. 6,1 tadi pagi, pada bulan Januari 2022 sudah terjadi 2 gempa tidak dirasakan. pic.twitter.com/IWQvwvAlVY — DARYONO BMKG (@DaryonoBMKG) February 25, 2022 Pasca Gempa di Pasaman Barat semburkan air panas di Bonjol Sumatera Barat. — David Haris St Parmato (@DavidHaris10) February 25, 2022 Ground failure pasca gempa kuat. https://t.co/2ApLwk83aq — DARYONO BMKG (@DaryonoBMKG) February 25, 2022 Vibrasi periode panjang terjadi di Malaysia saat gempa M6,1 Pasaman. https://t.co/zCegE51eI9 — DARYONO BMKG (@DaryonoBMKG) February 25, 2022
I was returning from New Orleans where I was attending the American Geophysical Union Fall Meeting. There was a short layover in Denver and I had a short time to find some food, which is challenging with my dietary restrictions. I cannot recall precisely, but I got some notification from my CGS crew about a magnitude M 6.2 earthquake offshore of the Mendocino triple junction. One of these notifications was from Cindy as we both collaborate to prepare quick reports for earthquakes in California. These reports are sent upstream to management in our organization and others. I was unavailable to contribute this time. Needless to say, I was sad to have missed experiencing this good sized shaker for myself. This is the first earthquake of this size that I have missed (in Humboldt) since I moved here in 1991. Last week or so, their analyses were produced publicly and the earthquake catalog was updated. What we discovered is that there were two closely spaced (in time but not space) earthquakes, an M 5.7 and and M 6.2. https://earthquake.usgs.gov/earthquakes/eventpage/nc71127029/executive It was complicated for the seismologists to work out because the seismic waves of the two events overlapped in time. i.e., the waves from the first quake were still passing through the Earth when the waves from the second quake started. Basically, there was initially an M 5.7 strike-slip earthquake along the Mendocino transform fault zone about 20 km (12.5 miles) offshore. About 10 or 11 seconds later, there was an M 6.2 strike-slip earthquake within the Gorda plate, below the megathrust fault. Here is a plot from the USGS. Each horizontal squiggly line is the seismograph record from an individual seismometer. They are plotted with the seismometer closest to the earthquake on the bottom row and the furthest seismometer on the uppermost row. The P wave (primary wave) is the first of four major types of seismic waves. Next comes the S (secondary) wave, then the Love waves, and finally the Raleigh waves. The P wave arrives at closer seismometers before it arrives at more distant seismometers. Because of this, we generally call this type of plot a travel time plot. In the above plot we can see how the M 6.1 P waves are arriving while the M 5.7 S waves are still being transmitted. The M 5.7 is clearly a right-lateral strike-slip event given the aftershock pattern and the known location and type of the Mendocino fault system (a right-lateral strike-slip fault. Earthquake mechanisms (the “beach balls”) show two possible ways that the earthquake could have slipped. We use aftershock patterns and existing mapped faults to help us interpret which of these [nodal] fault planes is the more likely one. If we look at the earthquake poster below, we see that the M 6.2 earthquake is an almost pure strike-slip earthquake. The two possible fault planes are one that is oriented in the northwest direction (would be right-lateral) and one that is in the northeast direction (would be left-lateral). So, while most of our experience with the Gorda plate is with northeast oriented (striking) left-lateral strike-slip faults (e.g., 1980, 2010, 2014, etc.) it is possible that there are other faults, sub-parallel to the post-1992 seismicity trends, where the M 6.2 and other aftershocks were hosted. I mention these northwest trending faults in a recent Earthquake Report here. Something that is interesting is that the onshore events from this 20 Dec 2021 sequence are just to the north of the aftershocks from the 1992 sequence. They are at similar depths as those ’92 quakes and have similar earthquake mechanisms. As Spock would say, Fascinating. Dr. Anthony Lomax, famous for his work locating the hypocenter for the 1906 San Francisco Earthquake, has been developing excellent tools for seismologists ever since. He recently applied one of his new tools to locate earthquakes to the Mendocino triple junction region. I present some of his figures below. There are many different ways in which a landslide can be triggered. The first order relations behind slope failure (landslides) is that the “resisting” forces that are preventing slope failure (e.g. the strength of the bedrock or soil) are overcome by the “driving” forces that are pushing this land downwards (e.g. gravity). The ratio of resisting forces to driving forces is called the Factor of Safety (FOS). We can write this ratio like this: FOS = Resisting Force / Driving Force When FOS > 1, the slope is stable and when FOS < 1, the slope fails and we get a landslide. The illustration below shows these relations. Note how the slope angle α can take part in this ratio (the steeper the slope, the greater impact of the mass of the slope can contribute to driving forces). The real world is more complicated than the simplified illustration below. Landslide ground shaking can change the Factor of Safety in several ways that might increase the driving force or decrease the resisting force. Keefer (1984) studied a global data set of earthquake triggered landslides and found that larger earthquakes trigger larger and more numerous landslides across a larger area than do smaller earthquakes. Earthquakes can cause landslides because the seismic waves can cause the driving force to increase (the earthquake motions can “push” the land downwards), leading to a landslide. In addition, ground shaking can change the strength of these earth materials (a form of resisting force) with a process called liquefaction. Sediment or soil strength is based upon the ability for sediment particles to push against each other without moving. This is a combination of friction and the forces exerted between these particles. This is loosely what we call the “angle of internal friction.” Liquefaction is a process by which pore pressure increases cause water to push out against the sediment particles so that they are no longer touching. An analogy that some may be familiar with relates to a visit to the beach. When one is walking on the wet sand near the shoreline, the sand may hold the weight of our body generally pretty well. However, if we stop and vibrate our feet back and forth, this causes pore pressure to increase and we sink into the sand as the sand liquefies. Or, at least our feet sink into the sand. Below is a diagram showing how an increase in pore pressure can push against the sediment particles so that they are not touching any more. This allows the particles to move around and this is why our feet sink in the sand in the analogy above. This is also what changes the strength of earth materials such that a landslide can be triggered. Below is a diagram based upon a publication designed to educate the public about landslides and the processes that trigger them (USGS, 2004). Additional background information about landslide types can be found in Highland et al. (2008). There was a variety of landslide types that can be observed surrounding the earthquake region. So, this illustration can help people when they observing the landscape response to the earthquake whether they are using aerial imagery, photos in newspaper or website articles, or videos on social media. Will you be able to locate a landslide scarp or the toe of a landslide? This figure shows a rotational landslide, one where the land rotates along a curvilinear failure surface.
The Gorda and Juan de Fuca plates subduct beneath the North America plate to form the Cascadia subduction zone fault system. In 1992 there was a swarm of earthquakes with the magnitude Mw 7.2 Mainshock on 4/25. Initially this earthquake was interpreted to have been on the Cascadia subduction zone (CSZ). The moment tensor shows a compressional mechanism. However the two largest aftershocks on 4/26/1992 (Mw 6.5 and Mw 6.7), had strike-slip moment tensors. In my mind, these two aftershocks aligned on what may be the eastern extension of the Mendocino fault. However, looking at their locations, my mind was incorrect. These two earthquakes were not aftershocks, but were either left-lateral or right-lateral strike-slip Gorda plate earthquakes triggered by the M 7.1 thrust event. These two quakes appear to be aligned with the two northwest trends in seismicity and the 18 March 2020 M 5.2. The orientation of the mechanisms are not as perfectly well aligned, but there are lots of reasons for this (perhaps the faults were formed in a slightly different orientation, but have rotated slightly). There have been several series of intra-plate earthquakes in the Gorda plate. Two main shocks that I plot of this type of earthquake are the 1980 (Mw 7.2) and 2005 (Mw 7.2) earthquakes. I place orange lines approximately where the faults are that ruptured in 1980 and 2005. These are also plotted in the Rollins and Stein (2010) figure above. The Gorda plate is being deformed due to compression between the Pacific plate to the south and the Juan de Fuca plate to the north. Due to this north-south compression, the plate is deforming internally so that normal faults that formed at the spreading center (the Gorda Rise) are reactivated as left-lateral strike-slip faults. In 2014, there was another swarm of left-lateral earthquakes in the Gorda plate. I posted some material about the Gorda plate setting on this page.
Tectonic configuration of the Gorda deformation zone and locations and source models for 1976–2010 M ≥ 5.9 earthquakes. Letters designate chronological order of earthquakes (Table 1 and Appendix A). Plate motion vectors relative to the Pacific Plate (gray arrows in main diagram) are from Wilson [1989], with Cande and Kent’s [1995] timescale correction.
A: Mapped faults and fault-related ridges within Gorda plate based on basement structure and surface morphology, overlain on bathymetric contours (gray lines—250 m interval). Approximate boundaries of three structural segments are also shown. Black arrows indicated approximate location of possible northwest- trending large-scale folds. B, C: uninterpreted and interpreted enlargements of center of plate showing location of interpreted second-generation strike-slip faults and features that they appear to offset. OSC—overlapping spreading center.
Models of brittle deformation for Gorda plate overlain on magnetic anomalies modified from Raff and Mason (1961). Models A–F were proposed prior to collection and analysis of full-plate multibeam data. Deformation model of Gulick et al. (2001) is included in model A. Model G represents modification of Stoddard’s (1987) flexural-slip model proposed in this paper.
I don’t always have the time to write a proper Earthquake Report. However, I prepare interpretive posters for these events. FOS = Resisting Force / Driving Force When FOS > 1, the slope is stable and when FOS < 1, the slope fails and we get a landslide. The illustration below shows these relations. Note how the slope angle α can take part in this ratio (the steeper the slope, the greater impact of the mass of the slope can contribute to driving forces). The real world is more complicated than the simplified illustration below. My original Tweet: #EarthquakeReport for M7.2 #TremblementDeTerre #Terrremoto #Earthquake in #Haiti #HaitiEarthquake #HaitiEarthquake2021 updated poster: compare shaking intensity MMI and aftershock regions between 2010 M 7.0 & 2021 M 7.2 read more about 2010 M 7 Event https://t.co/KDzf1PtjyE pic.twitter.com/wIURgKsbOa — Jason "Jay" R. Patton (@patton_cascadia) August 15, 2021 Haiti's 1860 Jour de Pâques earthquakes may have released strain in key fault zone https://t.co/JKBJiHZ5jo #RSESpapers Stacey Martin & Susan Hough https://t.co/hz1uosClX3 pic.twitter.com/n2N6nblQui — ANU Earth Sciences 🌏 (@anuearthscience) July 14, 2022 Given the larger magnitude and farther west location of this 2021 Haiti quake relative to the 2010 earthquake, it is also worth noting the short time elapsed between the last historical sequence of large quakes on this fault. Fig from our 2012 paperhttps://t.co/zLQ8wSbtWr pic.twitter.com/ux17G6bz2F — Austin Elliott (@TTremblingEarth) August 14, 2021 Why was there a gap between the 2010 and 2021 Haiti earthquakes? Because a sequence of moderate quakes in 1860 released strain in the gap! https://t.co/rpuXfEw78G — Dr. Susan Hough 🦖 (@SeismoSue) July 15, 2022 I was excited to see & have a chance to comment on a study published in Science yesterday, discussed here. The response to the 2021 Nippes, Haiti, earthquake was very different from the response in 2010, 1/https://t.co/y6l3jjsAYQ — Dr. Susan Hough 🦖 (@SeismoSue) March 11, 2022 Saturday's M7.2 earthquake in Haiti was close to the 2010 M7.0 earthquake. Both events are devastating on their own but compounded by ongoing problems the region faces. Compare @IRIS_EPO's Teachable Moments: 2010 M7.0: https://t.co/FgYVeGH6Zy 2021 M7.2: https://t.co/z007x1QxC4 pic.twitter.com/VpkCSo90G2 — Southern California Earthquake Center (@SCEC) August 16, 2021 Here is a comparison of Peak Ground Acceleration (perceived shaking) for the January 2010 M7.0 and August 2021 M7.2* events. Note the notable difference at Port-au-Prince. #Haiti #Earthquake *ShakeMap (version 5) remains preliminary and subject to USGS updates. pic.twitter.com/AiH2FU1NeU — Steve Bowen (@SteveBowenWx) August 14, 2021
Yesterday as I was signing into work, my colleague Jackie Bott (a seismologist, seismic hazard/geology mapper, and on my tsunami team at CGS) mentioned the outer rise earthquake offshore of Chile that caused a small tsunami.
PAGER provides shaking and loss estimates following significant earthquakes anywhere in the world. These estimates are generally available within 30 minutes and are updated as more information becomes available. Rapid estimates include the number of people and names of cities exposed to each shaking intensity level as well as the likely ranges of fatalities and economic losses.
Yesterday’s M 6.4 is a strike-slip earthquake (look at the earthquake mechanism legend on the top center of the poster) and appears to have slipped along the Petrinja fault. This fault has different names in different papers (which is common), but this name comes from the European Database of Seismogenic Faults. There are many different ways in which a landslide can be triggered. The first order relations behind slope failure (landslides) is that the “resisting” forces that are preventing slope failure (e.g. the strength of the bedrock or soil) are overcome by the “driving” forces that are pushing this land downwards (e.g. gravity). The ratio of resisting forces to driving forces is called the Factor of Safety (FOS). We can write this ratio like this: FOS = Resisting Force / Driving Force When FOS > 1, the slope is stable and when FOS < 1, the slope fails and we get a landslide. The illustration below shows these relations. Note how the slope angle α can take part in this ratio (the steeper the slope, the greater impact of the mass of the slope can contribute to driving forces). The real world is more complicated than the simplified illustration below.
Location of the South Balkan extensional system (SBER) withing the eastern European region. The system today is within the southern Balkan region north of the North Anatolian fault (NAF), shown by the horizontal line patter. Retreating subduction zones and related backarc extensional areas for the Mediterranean region are shown in blue , and advancing subduction zones an related are a of backarc shortening are shown in red). Backarc extensional regions are shown by dotted pattern. KF = Kefalonia fault zone.
Map of the most important seismogenic faults
Digital terrain model of the Pannonian basin to show its position within the Alpine mountain belt and the location of different subunits.
Block model depicting the present position of the Alcapa and Tisza-Dacia terranes in the Carpathian embayment and the associated lithospheric and asthenosphericprocesses down to the upper mantle transition zone (inspired after Ustaszewski et al., 2008).
Map of the Neogene Pannonian Basin, showing depocenters of the subbasins. The associated Transylvanian (TR) and Vienna (V) basins are shown. Modified from Horvath (1985a).
Tectonic map of the Pannonian Basin and surrounding regions showing the main extensional faults of Neogene age. After Rumpler and Horvath (1988). Area of Pannonian Basin Tertiary rocks within the Alpine-Carpathian fold belts shown as white.
Model geometry and boundary conditions used in the finite element procedure. Note that a larger framework was created to minimize edge effects and errors. As a result, the ‘free’ edges are buffered but can be deformed on a small scale. For further discussion see text. The Adria–Europe rotation pole was taken from Ward (1994).
Best-fitting resultant stress pattern reflecting the combined effects of the applied boundary conditions (see insets), changing crustal thickness and two predefined weakness zones. (a), ( b) The edge at the Bohemian Massif is fixed and slightly deforming, respectively. In order to make direct comparison possible, the smoothed (observed) and calculated stress directions are superimposed.
Cartoon summarizing the main stress sources in the Alpine–Carpathian–Pannonian–Dinaric system applied in our finite element models. Buttresses are rigid crustal blocks indenting or blocking their surroundings. Dashed lines represent faults that were included during modelling. The kinematics of some major faults showing present-day activity are also shown (after Gerner et al. 1997) 1: Molasse belt; 2: Flysch belt; 3: internal units; 4: Neogene and Quaternary #EarthquakeReport poster for M6.4 strike-slip #Earthquake in #Croatia https://t.co/nWCoPdKZ68 high chance for liquefaction likely ruptured the Petrinja fault, thought to be capable of M6.5 eventshttps://t.co/4Agp4cBnrz pic.twitter.com/TLJkADieQZ — Jason "Jay" R. Patton (@patton_cascadia) December 30, 2020 today's epicenter of the earthquake pic.twitter.com/OTZN5jrRWJ — Tomislav Kelekovic (@tkelekovic) December 29, 2020 Here is some more liquefaction on video https://t.co/EPOygT9shI — Marko (@Marko61511524) December 29, 2020 Photo of a sand boil(?) (indicating subsurface liquefaction) from the M6.4 #CroatiaEarthquake near #Petrinja. Seismic shaking increases pressure in water-filled pores between sand grains until the lose contact w/ each other, start acting like liquid (Photo from @LastQuake app) pic.twitter.com/09aoP2Hl03 — Brian Olson (@mrbrianolson) December 29, 2020 Preliminary automatic scenario of expected permanent deformations for the M 6.4 #Croatia #Earthquake. Waiting for other solutions and, of course, InSAR data. With @antandre71 pic.twitter.com/I78q9lpJ1Z — Simone Atzori (@SimoneAtzori73) December 29, 2020 #ERCC #DailyMap: 2020-12-30 ⦙ <p>Croatia | 6.4M Earthquake of 29 December</p> ▸https://t.co/OWf76WHpXL pic.twitter.com/Y4YsXLxEIy — Copernicus EMS (@CopernicusEMS) December 30, 2020 Best candidate fault structure for today's M6.4 #earthquake near Petrinja & Sisak, Croatia; NW-SE trending Petrinja fault zone (red arrows – HRCS027 in SHARE db) clearly visible in the terrain morphology. Epicenters (yellow) from @EMSC, foc mechs from GFZ. pic.twitter.com/dgeCep2ZUF — Sotiris Valkaniotis (@SotisValkan) December 29, 2020 This video compilation of footage from the M6.3 in Croatia has quite a number of remarkable perspectives, including — Austin Elliott (@TTremblingEarth) December 30, 2020 Sentinel-1 coseismic interferogram of the M6.3 Petrinja/Sisak earthquake #potres from ascending track @SotisValkan @EricFielding @gfun @LastQuake @JosipStipcevic pic.twitter.com/wreomZH1QG — Marin Govorcin (@Govorcin) December 30, 2020 M6.4 Petrinja, Croatia (2020.12.29)https://t.co/J82bValkmu Sentinel path 146 (2020.12.24-2020.12.30) pic.twitter.com/NfLG80tLWJ — gCent (@gCentBulletin) December 30, 2020 #EarthquakeReport for M6.4 #Earthquake in #Croatia #CroatiaEarthquake videos confirm liquefaction as suggested by USGS #liquefaction susceptibility model tectonic background here:https://t.co/ie8S2LGJeT pic.twitter.com/01ZKZD5bAI — Jason "Jay" R. Patton (@patton_cascadia) December 31, 2020 Magnitude 6.4 Earthquake in Croatia Kills at Least 7, Cuts Power and Water for Tens of Thousands https://t.co/Zaxkke9Dyg — Democracy Now! (@democracynow) December 31, 2020 #Sentinel-1 co-seismic deformation map and 3D displacement view (exaggerated) of 29.12.2020 M 6.4 #Petrinja, #Croatia #earthquake. Positive values (blue) indicate upward displacements. InSAR data obtained from COMET-LiCS database. pic.twitter.com/rGCO2otqHG — Reza Saber (@Geo_Reza) December 31, 2020 Today's 2020-12-29 M6.4 #Croatia #earthquake waves as seen from #Europe's #seismograph network via Ground Motion Visualization. The video does not reflect the actual speed of the waves. Time is shown at the bottom right. Code by @IRIS_EPO, with some preprocessing. @EGU_Seismo pic.twitter.com/EJAtqyqAFb — Giuseppe Petricca (@gmrpetricca) December 29, 2020 Enough with pain, loss and disasters in 2020. — Asieh Namdar (@asiehnamdar) December 30, 2020 #30Dicembre #30December #December30 2020 Earthquake Mw 6.4 Shakemovie – Animations of seismic wave propagation on the earth's surface (source INGV Italy)#earthquake #potres #terremoto #Petrinja #Croatia #Croazia #Hrvatska pic.twitter.com/4UeO74zwkT — geocappiello (@geocappiello) December 30, 2020 The largest onshore earthquake rupture in Europe since Norcia 2016. Copernicus #Sentinel1 co-seismic interferogram (ascending) for the M6.4 Petrinja, Croatia #earthquake. Shallow NW-SE 15-20km rupture along the fault scarp just west of Petrinja. pic.twitter.com/kB5bTuFV5X — Sotiris Valkaniotis (@SotisValkan) December 30, 2020 A number of large #landslides were triggered (with a few cm of displacement) by the M6.4 Petrinja, Croatia #earthquake – identifiable in the #Sentinel1 interferogram in distances as far as 30km from the earthquake rupture. pic.twitter.com/BBR8lgjwCH — Sotiris Valkaniotis (@SotisValkan) December 31, 2020 A damaging M6.4 #earthquake rattled #Croatia today, centered near Petrinja. It appears to have struck on a strike slip fault. This quake came a day after a M5.2 quake struck just to the northwest. Today’s quake was felt throughout the region. https://t.co/Zhezg7qu4U — temblor (@temblor) December 29, 2020 Efforts to assess the damage from yesterday’s magnitude-6.4 earthquake in Central Croatia continue. https://t.co/tMTXrys1RH — temblor (@temblor) December 30, 2020 — Marin Govorcin (@Govorcin) December 31, 2020 Here is a newly received picture following #CroatiaEarthquake It is liquefaction. Please read previous tweets for explanations pic.twitter.com/2iTjSse1Co — EMSC (@LastQuake) January 1, 2021 #EarthquakeReport update for #Croatia #CroatiaEarthquake #Earthquake see aftershocks and intensities for both 22 March '20 M 5.3 and 29 Dec '20 M 6.4 events the rest of the original report:https://t.co/ie8S2LGJeT pic.twitter.com/JnVzX7xmzI — Jason "Jay" R. Patton (@patton_cascadia) January 3, 2021 [Update] We're studying the evolution of the #Croatia #seimic sequence after the #earthuqake a few days ago, and thought it could be worthwhle to share. — iunio iervolino (@iuniervo) January 2, 2021 A bit of #MondayDataViz. — Dr Stephen Hicks 🇪🇺 (@seismo_steve) January 4, 2021 Report on the M6.4 Petrinja #earthquake, Croatia (29/12/2020), by the Geological Survey of Croatia https://t.co/L3gRZztvZm pic.twitter.com/NLmJukz4m3 — Stéphane Baize (@stef92320) January 4, 2021 Aftershocks of this week’s damaging M6.4 #Petrinja #earthquake are migrating onto a mapped fault that cuts through the capital city of #Zagreb. https://t.co/bA9j0UARKp — temblor (@temblor) January 2, 2021 🗺 New map: [#EMSR491] Petrinja Town: Grading Product, version 1, release 1, Vector Package [v1, 1:] — Copernicus EMS (@CopernicusEMS) December 31, 2020
Well, the east side of the Sierra lives up to its reputation for being in earthquake country. From the July 2019 Ridgecrest Earthquake Sequence (reports here)to some shakers east of Mono Lake, to the May 2020 Monte Cristo Earthquake Sequence (report here) to some earthquakes in the Owens Lake area of California. Residents of Olancha, Lone Pine, and Keeler felt strong shaking from a magnitude M 5.8 earthquake, also preceded by about 2 days with a M 4.6 temblor.
Simplified tectonic map of the western U.S. Cordillera showing the modern plate boundaries and tectonic provinces. Basin and Range Province is in medium gray; Central Nevada seismic belt (CNSB), eastern California shear zone (ECSZ), Intermountain seismic belt (ISB), and Walker Lane belt (WLB) are in light gray; Mina deflection (MD) is in dark gray.
Overview of active faults and regional topography of the Eastern California shear zone (ECSZ) and southern Walker Lane belt. Labeled faults are abbreviated as follows: ALF—Airport Lake fault, BF—Blackwater fault, GF—Garlock fault, KCF—Kern Canyon fault, LLF—Little Lake fault, OVF—Owens Valley fault, SNFF—Sierra Nevada frontal fault. OL—Owens Lake, IWV—Indian Wells Valley. Major historical earthquake surface ruptures in the Eastern California shear zone and Walker Lane belt are outlined in white, with stars denoting epicentral locations: OV—1872 Owens Valley, L—Landers 1992, HM—1999 Hector Mine. Active fault traces are taken from the U.S. Geological Survey Quaternary fault and fold database, with the exception of the Kern Canyon fault, taken from Brossy et al. (2012).
Shaded relief index map of Quaternary faults, roads, towns, and fi eld trip stops in the eastern California shear zone. Most faults are from the U.S. Geological Survey Quaternary fault and fold database (http://earthquake.usgs.gov/regional/qfaults). Arrows indicate relative fault motion for strike slip faults. Bar and circle indicates the hanging wall of normal faults. Field trip stop location numbers are tied to site descriptions in the fi eld guide section. AHF—Ash Hill fault; ALF—Airport Lake fault; B—Bishop; BF—Blackwater fault; BLF—Bicycle Lake fault; BM—Black Mountains; BP—Big Pine; Br—Baker; Bw—Barstow; By—Beatty; CA—California; CF—Cady fault; CLF—Coyote Lake fault; CoF—Calico fault; CRF—Camp Rock fault; DSF—Deep Springs fault; DV-FLVF—Death Valley–Fish Lake Valley fault; EPF—Emigrant Peak fault; EV— Eureka Valley; FIF—Fort Irwin fault; FM—Funeral Mountains; GF—Garlock fault; GFL—Goldstone Lake fault; GM—Grapevine Mountains; HF—Helendale fault; HLF—Harper Lake fault; HMSVF—Hunter Mountain–Saline Valley fault; I—Independence; LF—Lenwood fault; LLF— Lavic Lake fault; LoF—Lockhart fault; LP—Lone Pine; LuF—Ludlow fault; LV—Las Vegas; M—Mojave; MF—Manix fault; NV—Nevada; O—Olancha; OL—Owens Lake; OVF—Owens Valley fault; P—Pahrump; PF—Pisgah fault; PV—Panamint Valley; PVF—Panamint Valley fault; R—Ridgecrest; S—Shoshone; SAF—San Andreas fault; SDVF—southern Death Valley fault; SLF—Stateline fault; SPLM—Silver Peak–Lone Mountain extensional complex; SNF—Sierra Nevada frontal fault; SP—Silver Peak Range; T—Tonopah; TF—Tiefort Mountain fault; TMF—Tin Mountain fault; TPF—Towne Pass fault; WMF—White Mountains fault; YM—Yucca Mountain.
Simplified geologic map of the Little Lake fault, highlighting Quaternary volcanic and alluvial deposits bearing on the Pleistocene drainage of Owens River through the Little Lake area. Map units are named and modified from Duffield and Bacon (1981). The 30 m elevation contours are taken from the National Elevation Database (NED). The 40Ar/39Ar dates are labeled as in Table 1. SNFF—Sierra Nevada frontal fault.
Northward branching of the Holocene-active Airport Lake fault zone in northern Indian Wells Valley, Rose Valley, the Coso Range, and Wild Horse Mesa. AL—Airport Lake playa; BR— basement ridge; CB—Central branch; CWF—Coso Wash fault; EB—Eastern branch; GF—geothermal field; HS— Haiwee Spring; LCF—Lower Cactus Flat; MF—McCloud Flat; UCF—Upper Centennial Flat; WB—Western branch; WHA—White Hills anticline; WHM—Wild Horse Mesa; WHMFZ— Wild Horse Mesa fault zone. Faults with especially prominent scarps in Wild Horse Mesa are highlighted in bold. Late Quaternary faults modified from Duffield and Bacon (1981) and Whitmarsh (1998), with additional original mapping. A and B indicate two faults that display evidence for late Quaternary dextral offset.
Map showing interpreted thickness of Cenozoic deposits and major faults outlining the deep basins, based on inversion of gravity data [56]. Connection between West Inyo and Southwest Argus faults from Pluhar et al. [58]. ALFZ = Airport Lake Fault Zone; CWF = Coso Wash Fault; EIF = East Inyo Fault; LLF = Little Lake Fault. A-A’ to H-H’ indicate lines of cross sections and gravity profiles shown in Figure 10.
Map showing deep basins, relatively shallow down-dropped blocks, extended mountain blocks, and structural zones in the ESVS, which is bounded by largely unextended mountain blocks. CB = Chalfant Basin; NBB = North Bishop Block; RVB = Round Valley Basin
A: Index map of southwest North America showing geodetic provinces from Bennett et al. (2003) and location of Mojave block. Velocities of geodetically stable regions are shown relative to Colorado Plateau. ECSZ—eastern California shear zone in Mojave block. Shear zone continues northward into western Great Basin province. GF—Garlock fault. B: Index map of the Mojave block with active faults and locations of recent earthquake ruptures. Circles show localities of slip-rate measurements that sum to ≤6.2 ± 1.9 mm/yr across the ECSZ. GPS—global positioning system.
Map showing sites of slip rate studies in southern California for the San Andreas (SAI-14), San Jacinto (SJI-13), Elsinore-Whittier (El-8), Newport- Inglewood (N1-3), Palos Verdes (N4-6), Rose Canyon (N7), Transverse Ranges (T1-50), Mojave (MI-6), and Garlock (G1-9) faults.
A: Index map of Pacific–North America plate boundary through southwest North America. Principal faults are shown as thick black lines. Tectonically stable areas are outlined by dotted lines. Walker Lane and Eastern California shear zone, shown as dark gray band encompassing network of active faults, together absorb 9%–23% of total plate boundary shear (Dixon et al., 2000; Dokka and Travis, 1990a). JDF—Juan de Fuca; MTJ— Mendocino triple junction. B: Index map of Eastern California shear zone showing fault slip rates (in parentheses, mm/yr) determined by paleoseismic studies (Klinger and Piety, 2000; Lee et al., 2001; McGill and Sieh, 1993; Rockwell et al., 2000; Zhang et al., 1990). Heavy dark gray lines outline historic earthquake ruptures (Beanland and Clark, 1994; Sieh et al., 1993; Treiman et al., 2002). Heavy, medium gray band highlights Blackwater–Calico fault system. Light gray band surrounding Blackwater fault and passing north of Garlock fault is zone of localized 1.2 6 0.5 mm/yr strain accumulation documented by radar interferometry (Peltzer et al., 2001). C: Neotectonic map of Blackwater fault, showing type and orientation of fault line scarps with ticks on downthrown side. Dark patterned areas are lava flows cut by Blackwater fault (Dibblee, 1968, 1967; Smith, 1964)
Tectonic map of southern California. Solid lines are active faults (Jennings, 1975). Yellow dots are relocated earthquakes between 1981 and 2000 (Hauksson, 2000). Dashed-line box is area covered by Earth Resource Satellite (ERS) data used in this study. White dashed line shows location of concentrated shear observed in synthetic aperture radar (SAR) data. Black stars indicate epicenters of recent earthquakes: OV—1872 Owens Valley, JT—1992 Joshua Tree, L—1992 Landers, BB—1992 Big Bear, N—1994 Northridge, RC—1994 and 1995 Ridgecrest, HM—1999 Hector Mine. Heavy solid lines depict surface ruptures of Landers (Sieh et al., 1993), Hector Mine (U.S. Geological Survey and California Division of Mines and
In this model the Owlshead and southern Panamint blocks are hypothesized to have undergone sinistral transtension in response to a clockwise rotation of their southern confining boundary (Garlock fault zone).
Map showing the location of the ECSZ, the GPS arrays, the station velocities (relative to the fixed North America), and the principal faults in southern California (from Jennings [1992]). The thick dashed lines directed N23°W show the boundaries of the assumed parallel-sided ECSZ. The thin dashed lines extended from the segments of the Garlock fault show the trends of the segments.
Comparison of geologic fault slip rates (blue, mm/yr) used in model, range of estimates from elastic block models (black) of Becker et al. (2005) and Meade and Hager (2005), and estimates from our block model (magenta) along major faults. Negative is left lateral. Light red lines are surface fault traces, and white thick lines are model blocks. Blue arrows are Southern California Earthquake Center (SCEC) crustal motion map 3 (Shen et al., 2003) velocities with respect to stable North America.
Summary of assumed geologic rates, recurrence interval (T), and time since last earthquake (teq) in Southern California. (For further discussion of sources of T and teq, see footnote 1). Blue numbers are expert opinion slip rates from Working Group on California Earthquake Probabilities (2008) and red numbers are rates from other paleoseismology data.
A: Geologic fault slip rates versus slip rates inferred from geodetic data. Geologic rates are summarized in Table DR1 (see footnote 1). Blue bars are slip rate comparisons from Meade and Hager (2005) and red bars are from this study. B: Normalized velocity across Garlock fault (blue), Mojave segment of San Andreas fault (red), and eastern California shear zone (ECSZ, green) from our cycle model. Black line is normalized velocity derived from elastic model.
Sketch map of study area, modified from Dixon et al. (1995). Bar marks approximate location of Global Positioning System transect (Gan et al., 2000). GF— Garlock fault. Labeled faults of Eastern California shear zone: ALF— Airport Lake fault zone; OVF—Owens Valley fault zone; HMF—Hunter Mountain–Panamint Valley fault zone; DVF— Death Valley–Furnace
Global Positioning System velocity (triangles) and one standard error (bars) from Gan et al. (2000) compared to prediction of viscoelastic coupling model (heavy solid line), representing summed velocity contributions from four parallel faults (light dashed lines). SAF—San Andreas fault; DVF—Death Valley–Furnace Creek fault zone; HMF—Hunter Mountain–Panamint Valley fault zone; OVF—Owens Valley fault zone. Inset shows model rheology for Eastern California shear zone. SNB—Sierra Nevada block;B&R— Basin and Range Province; h is fault depth (depth of elastic layer) for three faults (a, b, or c), m is rigidity, h is viscosity. Arrows mark location of major shear-zone faults.
Surface velocity map obtained by averaging 25 interferograms of Los Angeles–Mojave region. One color cycle depicts 10 mm/yr of surface displacement along radar line of sight (at lat N348; ERS [Earth Resource Satellite] descending track trends S13.68W, radar looking westward at 238 off vertical incidence angle in middle of imaged swath). Gray areas are zones of low phase coherence that have been masked in processing. Black lines are active faults (Jennings, 1975). White box indicates subset of synthetic aperture radar (SAR) data that was used for profile in Figure 4. Note conspicuous shear strain along San Andreas fault and shear zone parallel to Blackwater–Little Lake fault system. Large deformation signal in northwest corner of frame is ground subsidence related to Coso volcanic and geothermal field (Fig. 1). Surface displacement associated with 1994 and 1995 Ridgecrest earthquakes is visible south of Coso area. Other patterns of surface deformation include ground subsidence due to groundwater withdrawal in Los Angeles and Lancaster areas (Fig. 1) and to seasonal change of water table level around dry lakes.
Profiles of observed and modeled line-of-sight displacement projected on vertical plane perpendicular to shear zone. Gray dots are individual data points for all radar-image pixels included in box shown in Figure 3. Solid line shows 2 km running mean of observed displacement along profile length. Note that apparent standard deviation of projected data relative to average profile reflects in part displacement gradient parallel to fault strike and not only error in data. Groups of dots that deviate from dense part of profile are due to ground subsidence near lake shores and to surface displacement associated with Ridgecrest earthquakes (Figs. 1, 3). Short-dash line is profile predicted by long-term velocity model used to estimate interferometric baseline (Shen et al., 1996). Long-dash line is profile predicted by velocity model, including additional buried dislocation along Blackwater–Little Lake fault system. Parameters of added fault are given in text. Black dots and error bars (2s) are line-of-sight projections of horizontal velocities observed by GPS at stations of Yucca transect (Gan et al., 2000).
Locations of the Golden Bear and Coso dikes, adjacent to Owens Valley. Main figure shows the Golden Bear and Coso dikes striking into the valley, where they intrude 102 Ma plutons. Both the dikes and the plutons provide distinctive markers that can be matched across the valley and are consistent with 65 km of dextral displacement since 84 Ma. Inset shows other markers across Owens Valley that earlier workers suggested indicate from 0 to 65 km of dextral offset across the valley. Also shown are the traces of the Tinemaha fault (Stevens et al., 1997; Stevens and Stone, 2002) and intrabatholithic break 3 (IBB3; Kistler, 1993), which are hypothesized to accommodate offset of these markers. Note that the section of IBB3 between 38°N and 36.5°N is correlative with the eastern intrabatholithic break (EIB) of Saleeby and Busby (1993). Not all known locations of Independence dikes are indicated. Instead, patterned areas show only the densest parts of the dike swarm as defi ned by Glazner et al. (2003). AR—Argus Range; CR—Coso Range; IR—Inyo Range; WM—White Mountains
(A) Map of major Quaternary faults in the northern Eastern California shear zone and southern and central Walker Lane, as well as the locations of the Owens Valley fault. Faults are modified from Reheis and Dixon (1996) and Wesnousky (2005)
Shaded relief map of southern Owens Valley showing fault zones and the ages of the most recent prominent highstands and recessional shorelines of Owens Lake during the latest Quaternary (modified from Bacon et al., 2006).
Map of the field area and locations of paleoseismic study sites in relation to the A.D. 1872 Owens Valley earthquake fault trace near Lone Pine. Study sites are located on the Alabama Hills (AHS), Diaz Lake (DLS), and Manzanar (MZS) sections of the Owens Valley fault zone mapped by Bryant (1988) and Beanland and Clark (1994) from 1:12,000 aerial photographs.
Schematic composite stratigraphic column. The generalized stratigraphic and geochronologic relations, developed from exposures at the Alabama Gates and Quaker paleoseismic sites and Owens River bluffs near Lone Pine (Bacon et al., 2006), show the positions of radiocarbon dates, sequence boundaries, and event chronologies as discussed in the text.
Schematic depiction of stratigraphy and structural relations at the Quaker paleoseismic site prior to the penultimate event and after the A.D. 1872 earthquake (depictions A–H). The stratigraphy and structure exposed in trench T5 (Fig. 7) was retrodeformed and reconstructed one event at a time (while also accounting for other stratigraphic and
Compilation of small geomorphic offsets measured from lidar using LaDiCaoz_v2 along average OVF strike (3408) (supporting information Tables S2 and S3). Data include confidence ratings of low-moderate to high and omit net values determined by summing. Gray error bars show uncertainty limits determined visually from back-slipping. (a) The spatial distribution of OVF scarps (red lines) mapped from EarthScope lidar and classified by Owens Valley fault section (orange and black points), following previous mapping by Beanland and Clark [1994], Bryant [1984a, 1984b], and Slemmons et al. [2008]. Nearby faults are taken from the U.S. Geological Survey Quaternary fault and fold database. From south to north: DS, Dirty Socks; OL, Owens Lake; LP, Lone Pine fault; DL, Diaz Lake; IS, southern Independence; MF, Manzanar fault; I, Independence; T, Tinemaha; TW, western Tinemaha; FS, Fish Springs; BP, Big Pine; K, Keough section of Sierra Nevada frontal fault (SNNF), KLF, Klondike Lake fault; KSF, Klondike Springs fault; WMF, White Mountain fault. (b) Right-lateral offset measurements symbolized by fault section include previously reported values (orange diamonds) from Bateman [1961], Lubetkin and Clark [1988], Beanland and Clark [1994], Lee et al. [2001a], Zehfuss et al. [2001], and Slemmons et al. [2008]. (c) Along-strike compilation of measured vertical throw. Throw is predominantly east-down, with negative values indicative of downward motion to the west.
Frequency distributions and cumulative offset probability density (COPD) plots for lateral and vertical offsets, compiled using bin sizes of 1 and 0.25 m, respectively (supporting information Tables S2 and S3). Histograms omit uncertainties, whereas COPD plots incorporate PDFs generated by the cross-correlation routine and truncated based on the range of uncertainty from back-slipping. Data are color-coded according to major sections of the OVF. (a) Scarps along the southern, central, and northern sections of the OVF relative to volcanic flows (purple) and a few representative elevation contours, generally corresponding to recognized pluviallacustrine features (#1–4) [Bacon et al., 2006; Jayko and Bacon, 2008; Bacon et al., 2013; Bacon et al., 2014]. Age estimates for features documented near (1) 1180 m, (2) 1162 m, (3) 1131 m, and (4) 1101 m are 160632 ka [Jayko and Bacon, 2008], 23,230–26,250 cal yr BP [Bacon et al., 2006], 15,870–16,230 cal yr BP [Bacon et al., 2014], and 300630 to 400630 yr BP [Bacon et al., 2013], respectively. Green points mark surface slip measurements based on geomorphic features. CM, Crater Mountain. Volcanic flows are from the California Geological Survey. (b–e) Optimum offset values for the southern (yellow), central (blue), and northern (red) sections are grouped and shaded by confidence rating. COPD plots use moderate to high confidence offsets and incorporate summed values.
Net 1872 surface slip derived from moderate to high confidence displacements plotted along subparallel strands. Gray bars reflect aggregated uncertainties from back-slipping of lidar imagery. (a) Along-strike compilation of displacement values for main traces of the OVF, as predicted by binned COPD plots. (b) Along-strike compilation of Lone Pine fault displacements. (c) Summed distributions (red lines) for possible net 1872 surface slip along a simplified
Compilation of reported slip rates in mm/yr on active faults in the southern Walker Lane (modified from Foy et al. [2012]) with rspect to the geodetic rate across the zone derived from the global positioning system and the relative motion of the Sierra Nevada– Great Valley microplate [Lifton et al., 2013]. Geologic slip rate studies, from south to north: Amos et al. [2013b], (this study), Oswald and Wesnousky [2002], Frankel et al. [2007a,b], Lubetkin and Clark [1988], Reheis and Sawyer [1997], Lee et al. [2001b], Ganev et al. [2010], Kirby et al. [2006], and Nagorsen-Rinke et al. [2013]. Faults listed alphabetically: AHF, Adobe Hills fault; ALF, Airport Lake fault; BMF, Black Mountain fault; DSF, Deep Springs fault; FCF, Furnace Creek fault; FLVF, Fish Lake Valley fault; HMF, Hunter Mountain fault; LLF, Little Lake fault; OVF, Owens Valley fault; NDVF, Northern Death Valley fault; PVF, Panamint Valley fault; QVF, Queen Valley fault; SAF, San Andreas fault; SNFF, Sierra Nevada frontal fault; SVF, Saline Valley fault; WMF, White Mountain fault.
Map of primary faults and rocks of the Big Pine volcanic field in south-central Owens Valley. The A.D. 1872 Owens Valley fault rupture and fault segments of the OVF and SNFF are shown (modified from Bacon and Pezzopane, 2007). Faults: CFF—Centennial Flat fault; KF—Keeler fault; ORF—Owens River fault; SFF—Sage Flat fault. Numbers show sites on OVF referred to in text of: 1—Kirby et al. (2008); 2—Lee et al. (2001); and 3—Bacon and Pezzopane (2007).
Map of primary faults in Owens Lake basin and elevations of deformed shoreline features (∼1156–1166 m) used to estimate the magnitude of ground deformation and slip rates across faults in the lake basin. Faults are modified after Bacon et al. (2005) and Slemmons et al. (2008). Faults: CFF—Centennial Flat fault; COLF—Central Owens Lake fault; IMF—Inyo Mountains fault; KF—Keeler fault; ORF—Owens River fault; OVF—Owens Valley fault; SIMF—southern Inyo Mountains fault; and SNFF—Sierra Nevada frontal fault. The location of the Sage Flat fault (SFF) after Jayko (2009) and Amos et al. (2013a) is also shown. Plunging anticlines from Frankel et al. (2008). Reference elevation contours at 1096 and 1160 m represent the margin of Owens Lake playa and the approximate location of ca. 40.0 ka shoreline features, respectively. Modern sill is also shown relative to the 1160 m elevation that defines the overflow channel of the basin. Sediment lake core OL92 of Smith and Bischoff (1997) is shown relative to the depocenter area of the lake basin. Approximate location of transect for repeat leveling surveys near Lone Pine of Savage and Lisowski (1980, 1995) is also shown. K—town of Keeler; S—Swansea embayment; O—town of Olancha.
Generalized fault map of Owens Lake basin showing slip rates from this study and previous investigations. Faults: CFF—Centennial Flat fault; COLF—Central Owens Lake fault; IMF—Inyo Mountains fault; KF—Keeler fault; ORF—Owens River fault; OVF—Owens Valley fault; SFF—Sage Flat fault; SIMF—southern Inyo Mountains fault; SNFF—Sierra Nevada frontal fault. Extension direction at N72°E normal to Owens Valley is shown with geologic extension rate from this study and geodetic extension rates from trilateration networks in the valley (Savage and Lisowski, 1995) and GPS arrays across northern Owens Valley (Ganev et al., 2010a). The location of transects A–A′, B–B′, and C–C′ used in cross sections are shown. K—town of Keeler; S—Swansea embayment.
Cross sections showing orientation of faults and sense of slip, and reconstructed water levels of the ca. 40 ka highstand pluvial lake in Owens Lake basin. Faults: CFF—Centennial Flat fault; COLF—Central Owens Lake fault; IMF—Inyo Mountains fault; KF—Keeler fault; ORF—Owens River fault; OVF—Owens Valley fault; SFF—Sage Flat fault; SIMF—southern Inyo Mountains fault; SNFF—Sierra Nevada frontal fault. Fault orientations are apparent dip based on fault strike across transects. Inferred locations of IMF and SIMF on transect A–A′ are from Pakiser et al. (1964) and Bacon et al. (2005).
Plots showing the elevation of: (A) deformed ca. 40 ka shoreline features and lowstand beach ridge deposits, and (B) ca. 15 cal k.y. B.P. shorelines features and deformed fluvial-deltaic deposits. The elevation of shoreline features and deposits are projected onto transect B–B′ and shown in relation to the generalized location of faults in Owens Lake basin (Fig. 9). Magnitude of ground deformation shown is ∼10 m subsidence relative to the ca. 40 ka reconstructed water level (i.e., paleohorizontal datum) and ∼3.6 m fault separation on the Keeler fault of the ca. 40 ka beach ridge crests. The elevation and age of fluvial deltaic deposits on the hanging wall of the Owens Valley fault are from paleoseismic fault trench data (Bacon and Pezzopane, 2007). Faults: CFF—Centennial Flat fault; COLF— Central Owens Lake fault; KF—Keeler fault; ORF—Owens River fault; OVF—Owens Valley fault; SIMF—southern Inyo Mountains fault; NFF—Sierra Nevada frontal fault. Actual dips of faults are not shown. Vertical sense of slip is indicated by arrows. Lateral slip is indicated by crosses (away) and dots (toward). The elevation errors from GPS survey of shoreline features and deposits are less than width of symbols.
Fault segmentation and section map of central and southern Owens Valley showing overlap and possible distributive faulting and linkage between the northern segment of the Owens Valley fault (OVF) and southern White Mountains fault (WMF) near Big Pine. The trace of the A.D. Owens Valley fault rupture and section boundaries of Beanland and Clark (1994) and segment boundaries of dePolo et al. (1991) are shown in relation to the central and southern White Mountains fault and the location of the Black Mountain rupture of dePolo (1989). RRF—Red Ridge fault; LP—Lone Pine; I—Independence; BP—Big Pine; OSL—optically stimulated luminescence; PE—Penultimate event; APE—antepenultimate event; MRE—most recent event.
#EarthquakeReport for M5.8 Owens Valley fault zone#Earthquake #Terremoto#Landslide #Liquefaction #Aftershocks prob (?) related to static coulomb stress changes following #RidgecrestEarthquake Sequence — Jason "Jay" R. Patton (@patton_cascadia) June 28, 2020 Deslizamientos de Tierra en las Montañas de Lone Pine, tras Terremoto de M6.1 en California, #US. (24.06.2020). #Earthquake #Nevada #Owens #Alico #Keeler #MT #Whitney #Sismo #Temblor #Landslide #zabedrosky By: Steven Wheeler ✓. pic.twitter.com/YdtWiOdjVF — ⚠David de Zabedrosky🌎 (@deZabedrosky) June 24, 2020 — Jason "Jay" R. Patton (@patton_cascadia) June 24, 2020 The 2019 M 7.1 Ridgecrest earthquake struck 50 mi to the south of today's quake. Temblor's forecast (Toda & Stein, BSSA, in press) suggests that stress transfer from the Ridgecrest events primed Lone Pine, and other areas, for subsequent quakes. pic.twitter.com/KHDNsckIOb — temblor (@temblor) June 24, 2020 — John Chrissinger (@JChrissinger) June 25, 2020 Auto solution FMNEAR (Géoazur/OCA) with regional records for the 2020-06-24 17:40:48.8 UTC M6.8 CENTRAL CALIFORNIA, USA (Loc EMSC used to trigger inversion).https://t.co/UHDsc1hVXA (not on mobile version) — Bertrand Delouis (@BertrandDelouis) June 24, 2020 When I got to the lower trailhead parking lot I saw this scar in the asphalt and an illegally parked boulder. “Something is *afoot*!”, I whispered to myself. #OwensLakeEarthqauke 4/ pic.twitter.com/1BeW9qEMOW — Brian OLSON-19 (@mrbrianolson) June 25, 2020 Recent Earthquake Teachable Moment | M5.8 earthquake near Lone Pine, CA IRIS Teachable Moments contains interpreted USGS regional tectonic maps and summaries, computer animations, seismograms, AP photos, and other event-specific information.https://t.co/GqGHSc2CA7 pic.twitter.com/zpQmFWHIvD — IRIS Earthquake Sci (@IRIS_EPO) June 25, 2020 Amazing that there are no documented injuries or missing people following yesterday’s 5.8 magnitude quake and resulting rockslide at Whitney Portal. Fingers crossed it stays that way. pic.twitter.com/4wm9ZCBxxP — Jacob Margolis (@JacobMargolis) June 25, 2020 The 5 Hz GPS velocities from yesterdays M5.8 Lone Pine earthquake show good correspondence with the existing ShakeMap. The triangles are the nearby seismic sites. @UNAVCO pic.twitter.com/Vbz6JdLnTR — Brendan Crowell (@bwcphd) June 25, 2020 Surface deformation revealed by Sentinel-1 interferogram of the Mw 5.8 #LonePine #earthquake . pic.twitter.com/N7AZLm0nwj — Kang Wang (@kjellywang) June 27, 2020 M5.8 Lone Pine, CA (2020.06.24)https://t.co/SIueo6em6W — gCent (@gCentBulletin) June 27, 2020 The cumulative stress change caused by the 2019 Ridgecrest sequence (Mw6.4 and Mw7.1) show a positive stress loading (in red) on the Mw 5.8 Lone Pine earthquake (orange circle). pic.twitter.com/R1IuVUu2pN — Jugurtha Kariche (@JkaricheKariche) June 25, 2020 Lone Pine is well worth the visit. And the 1872 event is memorialized there with a plaque in town and the group grave just north of town where 27 people who died in the quake were buried. pic.twitter.com/7m11lu98jw — Dan Brekke (@danbrekke) June 24, 2020 Today's T64 #Sentinel1 interferograms for the M5.8 Lone Pine / Owens Lake Ca #earthquake were really bad – so let's stick to the first one (T144) from yesterday. 2-3cm of LOS ground displacement over Owens Lake area. #InSAR proc. at @esa_gep. Epicenters, faults & FM from USGS 1/2 pic.twitter.com/N9syXVzVm9 — Sotiris Valkaniotis (@SotisValkan) June 28, 2020 A 3D of the rock fall/debris location in the Lone Pine slope over Whitney Portal. #landslides triggered from the M5.8 June 24 earthquake. #Sentinel2 image from June 27 2020. pic.twitter.com/nt1bIqeWEm — Sotiris Valkaniotis (@SotisValkan) June 28, 2020
Early morning (my time) there was an intermediate depth earthquake in the Banda Sea.
Regional tectonic setting with plate boundaries (MORs/transforms = black, subduction zones = teethed red) from Bird (2003) and ophiolite belts representing sutures modified from Hutchison (1975) and Baldwin et al. (2012). West Sulawesi basalts are from Polvé et al. (1997), fracture zones are from Matthews et al. (2011) and basin outlines are from Hearn et al. (2003).
Reconstructions of eastern Indonesia, adapted from Hall (2012), depict collision of Australia with Southeast Asia and slab rollback into Banda Embayment. Yellow star indicates Seram. Oceanic crust is shown in purple (older than 120 Ma) and blue (younger than 120 Ma); submarine arcs and oceanic plateaus are shown in cyan; volcanic island arcs, ophiolites, and material accreted along plate margins are shown in green. A: Reconstruction at 15 Ma. B: Reconstruction at 7 Ma. C: Reconstruction at 2 Ma. D: Visualization of present-day slab morphology of proto–Banda Sea based on earthquake hypocenter distribution and tomographic models
The Banda arc and surrounding region. 200 m and 4,000 m bathymetric contours are indicated. The numbered black lines are Benioff zone contours in kilometres. The red triangles are Holocene volcanoes (http://www.volcano.si.edu/world/). Ar=Aru, Ar Tr=Aru trough, Ba=Banggai Islands, Bu=Buru, SBS=South Banda Sea, Se=Seram, Sm=Sumba, Su=Sula Islands, Ta=Tanimbar, Ta Tr=Tanimbar trough, Ti=Timor, W=Weber Deep.
Tomographic images of the Banda slab. Vertical sections through the tomography model along the lines shown in Fig. 1. Colours: P-wave anomalies with reference to velocity model ak135 (ref. 30). Dots: earthquake hypocentres within 12 km of the section. The dashed lines are phase changes at ~410 km and ~660 km. The sections are plotted without vertical exaggeration; the horizontal axis is in degrees. The labelled positive anomalies are the Sunda (Su) and Banda (Ba) slabs: BuDdetached slab under Buru, FlDslab under Flores, SDslab under Seram, TDslab under Timor. a, The Sunda slab enters the lower mantle whereas the Banda embayment slab is entirely in the upper mantle with the change under Sulawesi. b–e, Banda slab morphology in sections parallel to Australia plate motion shows a transition from a steep slab with a flat section (fs) (b) to a spoon shape shallowing eastward (c–e).
Illustration of major tectonic elements in triple junction geometry: tectonic features labeled per Figure 1; seismicity from ISC-GEM catalog [Storchak et al., 2013]; faults in Savu basin from Rigg and Hall [2011] and Harris et al. [2009]. Purple line is edge of Australian continental basement and fore arc [Rigg and Hall, 2011]. Abbreviations: AR = Ashmore Reef; SR = Scott Reef; RS = Rowley Shoals; TCZ = Timor Collision Zone; ST = Savu thrust; SB = Savu Basin; TT = Timor thrust; WT =Wetar thrust; WASZ = Western Australia Shear Zone. Open arrows indicate relative direction of motion; solid arrows direction of vergence.
Cartoon cross section of Timor today, (cf. Richardson & Blundell 1996, their BIRPS figs 3b, 4b & 7; and their fig. 6 gravity model 2 after Woodside et al. 1989; and Snyder et al. 1996 their fig. 6a). Dimensions of the filled 40 km deep present-day Timor Tectonic Collision Zone are based on BIRPS seismic, earthquake seismicity and gravity data all re-interpreted here from Richardson & Blundell (1996) and from Snyder et al. (1996). NB. The Bobonaro Melange, its broken formation and other facies are not indicated, but they are included with the Gondwana mega-sequence. Note defunct Banda Trench, now the Timor TCZ, filled with Australian continental crust and Asian nappes that occupy all space between Wetar Suture and the 2–3 km deep deformation front north of the axis of the Timor Trough. Note the much younger decollement D5 used exactly the same part of the Jurassic lithology of the Gondwana mega-sequence in the older D1 decollement that produced what appears to be much stronger deformation.
Topographic and tectonic map of the Indonesian archipelago and surrounding region. Labeled, shaded arrows show motion (NUVEL-1A model) of the first-named tectonic plate relative to the second. Solid arrows are velocity vectors derived from GPS surveys from 1991 through 2001, in ITRF2000. For clarity, only a few of the vectors for Sumatra are included. The detailed velocity field for Sumatra is shown in Figure 5. Velocity vector ellipses indicate 2-D 95% confidence levels based on the formal (white noise only) uncertainty estimates. NGT, New Guinea Trench; NST, North Sulawesi Trench; SF, Sumatran Fault; TAF, Tarera-Aiduna Fault. Bathymetry [Smith and Sandwell, 1997] in this and all subsequent figures contoured at 2 km intervals.
Plate boundary segments in the Banda Arc region from Nugroho et al (2009). Numbers inside rectangles show possible micro-plate blocks near the Sumba Triple Junction (colored) based on GPS velocities (black arrows) with in a stable Eurasian reference frame.
Schematic map views of kinematic relations between major crustal elements in the Sumba Triple Junction region. CTZ= collisional tectonic zone. Red arrow size designates schematic plate motion relations based on geological data relative to a fixed Sunda shelf reference frame (pin).
Well Well Well https://earthquake.usgs.gov/earthquakes/eventpage/us70008jr5/executive Idaho lies in the intersection of several different physiographic provinces. Physiographic provinces are areas of Earth that have landforms of similar shape. These landforms are largely caused by tectonics and climate (of course, the climate is controlled largely by tectonics, but there are other factors like the rotation of the planet, convection cells in the atmosphere, etc. well, those convection cells are also controlled by tectonics (i.e. where continents are) too. so, yes, tectonics controls everything (even though it does not). The two main physiographic provinces (also called geomorphic provinces, after the word “geomorphology” – the shape of the landscape) at play in central Idaho are the Basin and Range and the Rocky Mountains. Here is a view of the physiographic provinces in the USA. There are many different phases of tectonic deformation that formed the geomorphic provinces of North America, so take an historical geology course to learn more! In northern Idaho, there is additional period of tectonic deformation that left behind geologic structures that appear to be playing a part in the M 6.5 temblor. During the Eocene, there was a period of east-west extension that caused lots of faults to form. These faults have been inactive for a very long time. However, sometimes there are older inactive faults that are oriented optimally to be reactivated under newer and possibly different tectonic forces. One example of this is in the Gorda plate offshore of northern California. Faults formed along the spreading ridge (the Gorda Rise), initially formed as normal faults, are exposed to north-south oriented compression and reactivate as strike-slip faults. Here we are, in central Idaho, where there are some Basin and Range faults (generally northwest trending here) that have been responsible for very large historic earthquakes. A recent example of a Basin and Range fault earthquake happened in 2017 in southeastern Idaho, just south of the Snake River Plain (another geomorphic province, formed by the passage of the Yellowstone Hotspot). Here is my report for that earthquake. Over the past few years, there has been an increase in the amount of people making observations, looking at the academic and govt literature, and forming hypotheses about these events.It used to be just a few of us, but now the bug has spread and lots of people are part of this educational process. This all is expressed via social media (mostly on twitter), where peoples’ hypotheses are discussed, shot down, or synchronistically further developed to learn something new we were not expecting. I am a coauthor of a forthcoming paper where we discussed some of these events. This is where it happens, online and in real time. The same was true for this M 6.5 earthquake in Idaho. People started using existing data, using visualizations in Google Earth, and using all the tools we have at our desktop fingertips, to figure out what the heck happened in a remote region of Idaho. The main B&R normal fault that may be somehow related to the M 6.5 earthquake is the Sawtooth fault, a northwest trending (striking) fault that Dr. Glenn Thackray (2013) suggested was “Holocene Active.” (This means the last time it had a large earthquake was sometime during the Holocene, or during the last 12,000 years or so.) Here is a figure from Thackray et al. (2013) that shows the fault they observed (in the inset B, look at the shadow formed by the fault; the arrows are pointing at the fault scarp). This fault is listed as a high priority to be studied, yet there are no published records yet (Crone et al., 2009). One of the major older faults (Eocene age) that cuts through the center of Idaho is the Trans-Challis fault zones (TCFZ; Bennet, 1986). Based on the work of others (like Kiilsgaard et al., 1986), this fault is thought to be related to the extension from Eocene time and is possibly related to the volcanism and detatchemnt faulting associated with metamorphic core complexes. Most of the faults in the TCFZ are also normal faults (makes sense since they were formed from extension). However, there are lots of faults of different types as they can form is they are oriented in ways different than the normal faults. So, at second glance, the M 6.5 event may have been on one of these older faults associated with the TCFZ. Perhaps the pre-existing older fault, which was inactive, was oriented in the correct position to respond to the modern tectonic forces. Thus, this fault would be considered to be reactivated. At third glance, it is possible that the M 6.5 event happened on a fault not observed at Earth’s surface and could be related to the Sawtooth fault (or some other fault). The mechanism is not a purely strike-slip earthquake as it is not a 100% double-couple earthquake (a double couple is the type of force that is associated with the crust moving in one direction on one side of the fault and in the other direction on the other side of the fault). Someone has hypothesized that the M 6.5 earthquake may have been complicated and involved both normal and strike-slip faulting. I like this hypothesis as it fits my idea of an older fault being reactivated under a newer (modern = today) tectonic regime. Something else to note. I took a look at Wells and Coppersmith (1994). These authors use earthquake event data to prepare some empirical relations between earthquakes of various sizes, types,e tc. and the magnitude of those earthquakes. So we can take one parameter and estimate what another parameter may be. One thing we might do is estimate what the surface rupture length might it take to generate a M 6.5 earthquake. According to the Wells and Coppersmith (1994) empirical relations, there may be a surface rupture length of about 20 km. If we look at the aftershock sequence in the poster below, we might observe that the fault length may be about 24 km. So, while these are not the same thing, they are of about the same scale. (I used the relations in their figure 9) There are many different ways in which a landslide can be triggered. The first order relations behind slope failure (landslides) is that the “resisting” forces that are preventing slope failure (e.g. the strength of the bedrock or soil) are overcome by the “driving” forces that are pushing this land downwards (e.g. gravity). The ratio of resisting forces to driving forces is called the Factor of Safety (FOS). We can write this ratio like this: FOS = Resisting Force / Driving Force When FOS > 1, the slope is stable and when FOS < 1, the slope fails and we get a landslide. The illustration below shows these relations. Note how the slope angle α can take part in this ratio (the steeper the slope, the greater impact of the mass of the slope can contribute to driving forces). The real world is more complicated than the simplified illustration below. Landslide ground shaking can change the Factor of Safety in several ways that might increase the driving force or decrease the resisting force. Keefer (1984) studied a global data set of earthquake triggered landslides and found that larger earthquakes trigger larger and more numerous landslides across a larger area than do smaller earthquakes. Earthquakes can cause landslides because the seismic waves can cause the driving force to increase (the earthquake motions can “push” the land downwards), leading to a landslide. In addition, ground shaking can change the strength of these earth materials (a form of resisting force) with a process called liquefaction. Sediment or soil strength is based upon the ability for sediment particles to push against each other without moving. This is a combination of friction and the forces exerted between these particles. This is loosely what we call the “angle of internal friction.” Liquefaction is a process by which pore pressure increases cause water to push out against the sediment particles so that they are no longer touching. An analogy that some may be familiar with relates to a visit to the beach. When one is walking on the wet sand near the shoreline, the sand may hold the weight of our body generally pretty well. However, if we stop and vibrate our feet back and forth, this causes pore pressure to increase and we sink into the sand as the sand liquefies. Or, at least our feet sink into the sand. Below is a diagram showing how an increase in pore pressure can push against the sediment particles so that they are not touching any more. This allows the particles to move around and this is why our feet sink in the sand in the analogy above. This is also what changes the strength of earth materials such that a landslide can be triggered. Below is a diagram based upon a publication designed to educate the public about landslides and the processes that trigger them (USGS, 2004). Additional background information about landslide types can be found in Highland et al. (2008). There was a variety of landslide types that can be observed surrounding the earthquake region. So, this illustration can help people when they observing the landscape response to the earthquake whether they are using aerial imagery, photos in newspaper or website articles, or videos on social media. Will you be able to locate a landslide scarp or the toe of a landslide? This figure shows a rotational landslide, one where the land rotates along a curvilinear failure surface. Here is an excellent educational video from IRIS and a variety of organizations. The video helps us learn about how earthquake intensity gets smaller with distance from an earthquake. The concept of liquefaction is reviewed and we learn how different types of bedrock and underlying earth materials can affect the severity of ground shaking in a given location. The intensity map above is based on a model that relates intensity with distance to the earthquake, but does not incorporate changes in material properties as the video below mentions is an important factor that can increase intensity in places. There are landslide slope stability and liquefaction susceptibility models based on empirical data from past earthquakes. The USGS has recently incorporated these types of analyses into their earthquake event pages. More about these USGS models can be found on this page. I prepared some maps that compare the USGS landslide probability maps for the 2020 M 6.5 and 1959 M 7.3 Hebgen Lake earthquakes.
Nowicki Jessee and others (2018) is the preferred model for earthquake-triggered landslide hazard. Our primary landslide model is the empirical model of Nowicki Jessee and others (2018). The model was developed by relating 23 inventories of landslides triggered by past earthquakes with different combinations of predictor variables using logistic regression. The output resolution is ~250 m. The model inputs are described below. More details about the model can be found in the original publication. We modify the published model by excluding areas with slopes <5° and changing the coefficient for the lithology layer "unconsolidated sediments" from -3.22 to -1.36, the coefficient for "mixed sedimentary rocks" to better reflect that this unit is expected to be weak (more negative coefficient indicates stronger rock).To exclude areas of insignificantly small probabilities in the computation of aggregate statistics for this model, we use a probability threshold of 0.002.
Trans-Challis fault system and other selected geologic features in Pacific Northwest and southern British Columbia, Canada. Modified from Tipper et al. (1981); strontium data from Armstrong (1979) and Armstrong et al. (1977). Volcanics: 1—McAbee Basin; 2—Tranquille Basin; 3—Monte Lake Volcanics; 4—Torada graben; 5—Republic graben; 6—Kettle graben; 7—Clarno Volcanics; 8—Challis Volcanics; 9—Challis Volcanics in Owyhee County. Core complexes: A—Shuswap Complex; B—Valhalla gneiss dome and Passmore gneiss dome; C— Kcitie yueiss dome; D—Okanogan gneiss dome; E—Selkirk igneous complex (Kaniksu batholith); F—Spokane dome; 6—Boehls Butte Formation; H—Pioneer Mountain core complex; I—House Mountain metamorphic complex. X—Chilly Buttes; Borah Peak earthquake, October 28,1983. Dashdot line = boundary of Basin and Range province in Oregon.
Major geologic features of trans-Challis fault system in central Idaho. Modified from Kiilsgaard et al. (1986).
Tectonic map of the western United States, showing the major components of the Cordilleran orogenic belt. The initial Sr ratio line is taken to represent the approximate western edge of North American cratonic basement (Armstrong and others, 1977; Kistler and Peterman, 1978). Abbreviations as follows: CRO, Coast Range ophiolite; LFTB, Luning-Fencemaker thrust belt; CNTB, Central Nevada thrust belt; WH, Wasatch hinge line; UU, Uinta Mountains uplift; CMB, Crazy Mountains basin; PRB, Powder River basin; DB, Denver basin; RB, Raton basin. Precambrian shear zones after Karlstrom and Williams (1998).
Simplified version of figure 2, showing some of the major tectonic features in the Cordilleran thrust belt discussed in the text. Abbreviations as follows: LCL, Lewis and Clark line; SWMT, Southwest Montana transverse zone; CC, Cabin culmination; WC, Wasatch culmination; SAC, Santaquin culmination; SC, Sevier culmination; CNTB, Central Nevada thrust belt; LFTB, Luning-Fencemaker thrust belt; WH, Wasatch hinge line. Stippled region represents Cordilleran foreland basin system.
Location map of central Idaho showings elected Cenozoic normal faults. Solid triangles hows location of tilted Tertiary conglomerates in the footwall of the Pass Creek fault system. Widely-spaced diagonal rule shows Trans-Challis zone. Selected Tertiary plutons are cross-hatched. Small dots outline late Cenozoic basin fill. Numerous NE striking normal faults in the central Lost River Range are omitted for clarity. BPH is Borah Peak horst; WKH is White Knob horst; PCWC is Pass Creek-Wet Creek reentrant.
Northwest-southeast cross section of three NE striking normal faults. Volcanic rocks are stippled. Location of cross section is in above map. Restoration indicates 30% extension during synvolcanic faulting int he area. The Long Lost fault may have been reactivated.
Generalized map of southern Idaho showing major geologic and physiographic features and locations referred to in the text.
Surface-rupture extent of the 1983 Mw 6.9 Borah Peak earthquake (red), which ruptured the Thousand Springs and southernmost Warm Springs sections of the Lost River fault zone (LRFZ). The Willow Creek Hills are an area of hanging-wall bedrock and complex surface faulting that form a normal-fault structural barrier between the two sections. Yellow polygons show the extent of digital surface models generated in this study using low-altitude aerial imagery derived from unmanned aircraft systems. Fault traces and time of most recent faulting modified from U.S. Geological Survey (2018). Focal mechanism from Doser and Smith (1985); approximate location is 10 km south of figure extent (Richins et al., 1987). Triangles indicate paleoseismic sites: RC—Rattlesnake Creek; SC—Sheep Creek; PS—Poison Spring; DP—Doublespring Pass; EC—Elkhorn Creek; MC—McGowen Creek. Inset map shows regional context. LFZ—Lemhi fault zone; BFZ—Beaverhead fault zone; ESRP—Eastern Snake River Plain; INL—Idaho National Laboratory. Base maps are National Elevation Data set 10 m and 30 m (inset map) digital elevation models.
Vertical separation (VS) along the southern 8 km of Warm Springs section. (A) 1983 VS measured in this study (red) compared to those of Crone et al. (1987) (blue) for the 1983 surface rupture. RC shows displacement measured at the Rattlesnake Canyon trench (Schwartz, written communication, 2016). (B) Cumulative VS for prehistoric scarps along the Warm Springs section, showing scarps having VS of ≤2 m (PE1; blue line and shading) and >2 m (PE2; magenta line and shading). Plus signs (1983 rupture) and circles (prehistoric) indicate preferred VS values; vertical lines show min-max VS range based on multiple VS measurement iterations.
Vertical separation (VS) along the 8-km-long Arentson Gulch fault near the northernmost Thousand Springs section. (A) 1983 VS measured in this study (red) compared to those of Crone et al. (1987) (blue) for the 1983 surface rupture. (B) Cumulative VS for prehistoric scarps (squares), including VS for compound (including 1983 and prehistoric displacement) and single-event (prehistoric displacement only) scarps.
Summary of vertical separation (VS) along the Warm Springs and Thousand Springs sections. (A) Cumulative VS, showing Warm Springs section scarps (magenta and blue) and the 1983 rupture (red). Prehistoric scarps along the northern Thousand Springs section (gray circles; this study) show a pattern of VS decreasing toward the Willow Creek Hills that is similar to the 1983 (red) and prehistoric (green) VS curves for the Arentson Gulch fault. The VS curve for the 1983 rupture of the Thousand Springs section (kilometers 13–34) is fit to data reported in Crone et al. (1987). (B) Per-event vertical displacement based on mean displacement difference curves (see text for discussion). Along the Warm Poorly constrained, first-motion mechanism is similarhttps://t.co/X6uaWFVKia pic.twitter.com/9MTWWeo3SY — Anthony Lomax 🌍🇪🇺 (@ALomaxNet) April 1, 2020 #EarthquakeReport for #Idaho #Earthquake near #Stanley and #Challis #IdahoEarthquake updated @USGSBigQuakes landslide maps@IDGeoSurvey faults@IRIS_EPO sourced #AftershockUpdate! report w tectonic backgrhttps://t.co/cVonuc98VA pic.twitter.com/fAKT7YGsRA — Jason "Jay" R. Patton (@patton_cascadia) April 2, 2020 Epicenter of today's #idahoearthquake placed on our Miocene and Younger Fault map (M-8)-ZOOMED IN. It falls close to the trans-Challis faults system and northern end of the Basin and Range. Thanks @cmcfeeney for quick turn around. pic.twitter.com/egOkiwnj3F — ID Geological Survey (@IDGeoSurvey) April 1, 2020 Mw=6.4, WESTERN IDAHO (Depth: 16 km), 2020/03/31 23:52:31 UTC – Full details here: https://t.co/KoSYYgCGpJ pic.twitter.com/JtS0KbyVxj — Earthquakes (@geoscope_ipgp) April 1, 2020 See those waves on Lake Okanagan? It's a perfectly still day and no boats are out. That's from the earthquake in Idaho 10 min ago pic.twitter.com/ztFWWBErb8 — Molly Millions (@lilorphanammo) April 1, 2020 Exactly! There are many miocene-Quaternary faults documented by the Idaho Geologic Survey with similar north-northeast orientations pic.twitter.com/8DmoJmmosG — Colin Chupik (@ChupikColin) April 1, 2020 Geomorphically, there are some compelling uphill-facing scarps along the linear valley where the Idaho epicenter sits, precisely atop the "Pre-Miocene" strike-slip Trans-Challis Fault Zone. — Austin Elliott (@TTremblingEarth) April 1, 2020 Today's quake struck off the end of the Sawtooth Fault, which accommodates E-W stretching of the northern Basin and Range. Could the Sawtooth Fault now unzip? It happened before, in 1983, when the nearby Lost River Fault ruptured in an M 7.3 earthquake. pic.twitter.com/msbHRqg0Px — temblor (@temblor) April 1, 2020 The USGS ShakeMap of ground motion intensity has been updated since y'day, as new constraints have come in. Main new constraints appear to be the DYFI community responses, as new pockets of MMI V emerged in Snake River Plain towns with clusters of respondents but few seismometers https://t.co/ZPBcCugUBJ pic.twitter.com/iYNuuVpoGD — Austin Elliott (@TTremblingEarth) April 1, 2020 Watch the waves from the M6.5 Idaho earthquake roll across seismic stations in North America! (THREAD) #IdahoEarthquake #IdahoQuake pic.twitter.com/ZbWYe1svBe — IRIS Earthquake Sci (@IRIS_EPO) April 1, 2020 … "These earthquakes are caused by tectonic extension of the region and are not related to Yellowstone, nor will they have a significant impact on the Yellowstone system." — Dr Janine Krippner (@janinekrippner) April 1, 2020 Trying to decompose the moment tensor of M6.5 Idaho earthquake into two double couple mechanisms. It can be decomposed into an Mw6.5 strike-slip event plus an Mw6.1 normal event, which seems consistent with the local tectonics. A first-motion mechanism might offer additional info pic.twitter.com/xP8s5R0waV — Baoning Wu (@BoilingWoo) April 1, 2020 More Idaho earthquake fun in Jerome Idaho. Video from Tanner Bangerter #idahoquake #earthquake @CNN @BreitbartNews @FoxNews @NBCNews pic.twitter.com/8bgQ8LWS17 — Paul Dickinson (@pdicky77) April 1, 2020 A friend of mine sent these cool pictures of her sand pendulum. It recorded #earthquakeidaho! pic.twitter.com/sE1wCTsmmk — Geo_Sci_Jerry (@SciJerry) April 1, 2020 Our flight over the #IdahoEarthquake epicenter region north of Stanley was pretty uneventful in terms of observing earthquake effects. pic.twitter.com/M6esihwi2V — Zach Lifton (@zachlifton) April 2, 2020 Latest #Sentinel1 interferogram for M6.5 Idaho #earthquake; still low coherence from snow/forests but fringes & aftershocks hint at a NNW main fault plane, continuation of Sawtooth FZ? Rupture prob. more complex. Processed with DIAPASON at @esa_gep _gep #idahoearthquake pic.twitter.com/7Lfk0VFCCs — Sotiris Valkaniotis (@SotisValkan) April 5, 2020
Well, it was a big mag 5 day today, two magnitude 5+ earthquakes in the western USA on faults related to the same plate boundary! Crazy, right? The same plate boundary, about 800 miles away from each other, and their coincident occurrence was in no way related to each other. I was on the phone with my friend, collaborator, and business partner Thomas Harvey Leroy (the man with 4 first names: Tom, Harvey, Lee, and Roy) yesterday afternoon. We were determining the best course of action after a tenant of ours moved out leaving PG&E with an unpaid ~$9000 bill and we could not turn the power back on until the bill was paid. His son walked up to him and asked if what he had just felt was an earthquake. Because Tom was pacing back and forth, he did not feel it (as Tom likes to say, “feel the pain.”). He wishes that he had felt it. Well, they are not directly related to each other (i.e. none of these earthquakes caused any of the other earthquakes). The exception is that the 2019 M 5.6 may have affected the stress in the crust leading to the March M 5.2, but this is unlikely. What is even less likely that the M 5.8 was caused by the June 5.6 or caused the march 5.2. Below is a figure from Wells and Coppersmith (1994) that shows the empirical relations between surface rupture length (SRL, the length of the fault that ruptures to the ground surface) and magnitude. If one knows the SRL (horizontal axis), they can estimate the magnitude (vertical axis). The left plot shows the earthquake data. The right plot shows how their formulas “predict” these data.
(a) Regression of surface rupture length on magnitude (M). Regression line shown for all-slip-type relations. Short dashed line indicates 95% confidence interval. (b) Regression lines for strike-slip, reverse, and normal-slip relations. See Table 2 for regression coefficients. Length of regression lines shows the range of data for each relation. Using these empirical relations (which are crude and may not cover earthquakes as small as this M 5.8, but they are better than nothing), the “surface rupture length” of this M 5.8 might be about 5 km. So, changes in static coulomb stress from the M 5.8 extended, at most, about 16 km (or about 10 miles). Yesterday’s M 5.2. is about 72 km away, far too distant to be statically triggered by the 5.8. I also outlined the two main northwest trends in seismicity with dashed white line polygons. The 18 March event is in the southern end of the western seismicity trend.
The Gorda and Juan de Fuca plates subduct beneath the North America plate to form the Cascadia subduction zone fault system. In 1992 there was a swarm of earthquakes with the magnitude Mw 7.2 Mainshock on 4/25. Initially this earthquake was interpreted to have been on the Cascadia subduction zone (CSZ). The moment tensor shows a compressional mechanism. However the two largest aftershocks on 4/26/1992 (Mw 6.5 and Mw 6.7), had strike-slip moment tensors. In my mind, these two aftershocks aligned on what may be the eastern extension of the Mendocino fault. However, looking at their locations, my mind was incorrect. These two earthquakes were not aftershocks, but were either left-lateral or right-lateral strike-slip Gorda plate earthquakes triggered by the M 7.1 thrust event.
Tectonic configuration of the Gorda deformation zone and locations and source models for 1976–2010 M ≥ 5.9 earthquakes. Letters designate chronological order of earthquakes (Table 1 and Appendix A). Plate motion vectors relative to the Pacific Plate (gray arrows in main diagram) are from Wilson [1989], with Cande and Kent’s [1995] timescale correction.
A: Mapped faults and fault-related ridges within Gorda plate based on basement structure and surface morphology, overlain on bathymetric contours (gray lines—250 m interval). Approximate boundaries of three structural segments are also shown. Black arrows indicated approximate location of possible northwest- trending large-scale folds. B, C: uninterpreted and interpreted enlargements of center of plate showing location of interpreted second-generation strike-slip faults and features that they appear to offset. OSC—overlapping spreading center.
Models of brittle deformation for Gorda plate overlain on magnetic anomalies modified from Raff and Mason (1961). Models A–F were proposed prior to collection and analysis of full-plate multibeam data. Deformation model of Gulick et al. (2001) is included in model A. Model G represents modification of Stoddard’s (1987) flexural-slip model proposed in this paper.
If we move a little further north, we can take a look at the Blanco fault. This is a right-lateral strike-slip fault just like the Mendocino and San Andreas faults.
(Top) Sea Beam bathymetric map of the Cascadia Depression, Blanco Ridge, and Gorda Depression, eastern Blanco Transform Fault Zone (BTFZ).Multibeam bathymetry was collected by the NOAA R/V’s Surveyor and Discoverer and the R/V Laney Chouest during 12 cruises in the 1980’s and 90’s. Bathymetry displayed using a 500 m grid interval. Numbers with arrows show look directions of three-dimensional diagrams in Figures 2 and 3. (Bottom) Structure map, interpreted from bathymetry, showing active faults and major geologic features of the region. Solid lines represent faults, dashed lines are fracture zones, and dotted lines show course of turbidite channels. When possible to estimate sense of motion on a fault, a filled circle shows the down-thrown side. Inset maps show location and generalized geologic structure of the BTFZ. Location of seismic reflection and gravity/magnetics profiles indicated by opposing brackets. D-D’ and E-E’ are the seismic reflection profiles shown in Figures 8a and 8b, and G-G’ is the gravity and magnetics profile shown in Figure 13. Submersible dive tracklines from sites 1 through 4 are highlighted in red. L1 and L2 are two lineations seen in three-dimensional bathymetry shown in Figures 2 and 3. Location of two Blanco Ridge slump scars indicated by half-rectangles, inferred direction of slump shown by arrow, and debris location (when identified) designated by an ‘S’. CD stands for Cascadia Depression, BR is Blanco Ridge, GD is Gorda Depression, and GR is Gorda Ridge. Numbers on north and south side of transform represent Juan de Fuca and Pacific plate crustal ages inferred from magnetic anomalies. Long-term plate motion rate between the Pacific and southern Juan de Fuca plates from Wilson (1989).
When there are quakes on the BF, people always wonder if the Cascadia megathrust is affected by this… “are we at greater risk because of those BF earthquakes?”Earthquake Report M 7.0 Philippines
Because of this, I present Earthquake Report Lite. (but it is more than just water, like the adult beverage that claims otherwise). I will try to describe the figures included in the poster, but sometimes I will simply post the poster here.Below is my interpretive poster for this earthquake
I include some inset figures.
Philippines | Western Pacific
Earthquake Reports
References:
Basic & General References
Specific References
Social Media: Here is my thread for this event.
This has potential to be quite devastatingReturn to the Earthquake Reports page.
Earthquake Report: M 6.2 along the Great Sumatra fault
Below is a low-angle oblique view cut into the Earth showing this plate configuration from the Earth Observatory Singapore.
Because the convergence is at an angle oblique to the plate boundary, we can imagine that this convergence can be subdivided into two components of motion:
Below is my interpretive poster for this earthquake
I include some inset figures. Some of the same figures are located in different places on the larger scale map below.
Some Relevant Discussion and Figures
Earthquake Stress Triggering
Shaking Intensity
Potential for Ground Failure
There are many different ways in which a landslide can be triggered. The first order relations behind slope failure (landslides) is that the “resisting” forces that are preventing slope failure (e.g. the strength of the bedrock or soil) are overcome by the “driving” forces that are pushing this land downwards (e.g. gravity). The ratio of resisting forces to driving forces is called the Factor of Safety (FOS). We can write this ratio like this:
Seismic Hazard and Seismic Risk
Tsunami Hazard
Indonesia | Sumatra
General Overview
Earthquake Reports
Social Media
historical analogueshttps://t.co/Se0jsMEvGO
Hope everybody is OK in the epicentral area.https://t.co/0cddTk78dK pic.twitter.com/MW9G6IwTje
Padang Gempa Sumbar pic.twitter.com/cBBQka8hkj
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report: M 5.7 & 6.2 Mendocino triple junction
I got home about 3 am the next morning and did not have energy to prepare an earthjay report. Though I started working on it the next day. However, I soon learned that this was a complicated earthquake and I decided to await additional analyses by the Berkeley Seismmo Lab and the USGS.
https://earthquake.usgs.gov/earthquakes/eventpage/nc73666231/executive
The interpretation for the type of earthquake for the M 6.2 is a little more complicated.
There are two reasons why I interpret the M 6.2 to be right-lateral (of course, I could be wrong).
Below is my interpretive poster for this earthquake
I include some inset figures. Some of the same figures are located in different places on the larger scale map below.
Other Report Pages
Shaking Intensity and Potential for Ground Failure
Some Relevant Discussion and Figures
I have compiled some literature about the CSZ earthquake and tsunami. Here is a short list that might help us learn about what is contained within the core that I collected.
Cascadia subduction zone
General Overview
Earthquake Reports
Gorda plate
Blanco transform fault
Mendocino fault
Mendocino triple junction
North America plate
Explorer plate
Uncertain
Social Media
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report: M 7.2 in Haiti
Because of this, I present Earthquake Report Lite. (but it is more than just water, like the adult beverage that claims otherwise). I will try to describe the figures included in the poster, but sometimes I will simply post the poster here.
On 14 August ’21 there was a magnitude M 7.2 oblique strike-slip earthquake in Haiti. This earthquake was along the Enriquillo-Plantain Garden fault zone, which also ruptured in 2010. Here is my report for the 2010 Haiti earthquake (see more about the tectonics of this region of the world).
https://earthquake.usgs.gov/earthquakes/eventpage/us6000f65h/executiveBelow is my interpretive poster for this earthquake
I include some inset figures.
Earthquake Aftershocks
Potential for Ground Failure
There are many different ways in which a landslide can be triggered. The first order relations behind slope failure (landslides) is that the “resisting” forces that are preventing slope failure (e.g. the strength of the bedrock or soil) are overcome by the “driving” forces that are pushing this land downwards (e.g. gravity). The ratio of resisting forces to driving forces is called the Factor of Safety (FOS). We can write this ratio like this:
Landslide ground shaking can change the Factor of Safety in several ways that might increase the driving force or decrease the resisting force. Keefer (1984) studied a global data set of earthquake triggered landslides and found that larger earthquakes trigger larger and more numerous landslides across a larger area than do smaller earthquakes. Earthquakes can cause landslides because the seismic waves can cause the driving force to increase (the earthquake motions can “push” the land downwards), leading to a landslide. In addition, ground shaking can change the strength of these earth materials (a form of resisting force) with a process called liquefaction.
Sediment or soil strength is based upon the ability for sediment particles to push against each other without moving. This is a combination of friction and the forces exerted between these particles. This is loosely what we call the “angle of internal friction.” Liquefaction is a process by which pore pressure increases cause water to push out against the sediment particles so that they are no longer touching.
An analogy that some may be familiar with relates to a visit to the beach. When one is walking on the wet sand near the shoreline, the sand may hold the weight of our body generally pretty well. However, if we stop and vibrate our feet back and forth, this causes pore pressure to increase and we sink into the sand as the sand liquefies. Or, at least our feet sink into the sand.
Below is a diagram showing how an increase in pore pressure can push against the sediment particles so that they are not touching any more. This allows the particles to move around and this is why our feet sink in the sand in the analogy above. This is also what changes the strength of earth materials such that a landslide can be triggered.
Below is a diagram based upon a publication designed to educate the public about landslides and the processes that trigger them (USGS, 2004). Additional background information about landslide types can be found in Highland et al. (2008). There was a variety of landslide types that can be observed surrounding the earthquake region. So, this illustration can help people when they observing the landscape response to the earthquake whether they are using aerial imagery, photos in newspaper or website articles, or videos on social media. Will you be able to locate a landslide scarp or the toe of a landslide? This figure shows a rotational landslide, one where the land rotates along a curvilinear failure surface.
Caribbean
General Overview
Earthquake Reports
Social Media
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report: Croatia!
https://earthquake.usgs.gov/earthquakes/eventpage/us6000d3i9/executive
I checked this out and found a 20 cm wave height tsunami observed on a tide gage directly east of the earthquake epicenter. This was interesting as the earthquake was an “outer rise” event (seaward of the subduction zone trench, where the Nazca plate flexes downward prior to being subducted.
As the plate flexes downward, the upper part of the plate gets stretched and extensional faults can form here (or cause pre-existing faults to be reactivated as extensional/normal faults). For more background about different types of faults, head here: Earthquake Plate Tectonic Fundamentals page.
And, this M 6.7 earthquake was a normal fault earthquake (based on the earthquake mechanism). The largest tsunami waves can be generated by landslides or subduction zone faults, but other fault types can generate tsunami too (albeit smaller in size). Interesting indeed (there is more, like it is in a region of a triggered outer rise events following the 1960 M 9.5 Chile earthquake; is this M 6.7 an aftershock?, probably not).
BUT, this earthquake report is about the earthquake in Croatia that Jackie also mentioned in her email. Upon quick review, looking at the USGS PAGER Alert page, I knew that there was a high likelihood for casualties.
https://earthquake.usgs.gov/earthquakes/eventpage/us6000d3zh/executive
According to the database, the Petrinja fault is capable of a M 6.5 earthquake.Below is my interpretive poster for this earthquake
I include some inset figures. Some of the same figures are located in different places on the larger scale map below.
UPDATE: 2021.01.03 Aftershocks and Intensity Comparison.
Other Report Pages
Shaking Intensity and Potential for Ground Failure
Landslide ground shaking can change the Factor of Safety in several ways that might increase the driving force or decrease the resisting force. Keefer (1984) studied a global data set of earthquake triggered landslides and found that larger earthquakes trigger larger and more numerous landslides across a larger area than do smaller earthquakes. Earthquakes can cause landslides because the seismic waves can cause the driving force to increase (the earthquake motions can “push” the land downwards), leading to a landslide. In addition, ground shaking can change the strength of these earth materials (a form of resisting force) with a process called liquefaction.
Sediment or soil strength is based upon the ability for sediment particles to push against each other without moving. This is a combination of friction and the forces exerted between these particles. This is loosely what we call the “angle of internal friction.” Liquefaction is a process by which pore pressure increases cause water to push out against the sediment particles so that they are no longer touching.
An analogy that some may be familiar with relates to a visit to the beach. When one is walking on the wet sand near the shoreline, the sand may hold the weight of our body generally pretty well. However, if we stop and vibrate our feet back and forth, this causes pore pressure to increase and we sink into the sand as the sand liquefies. Or, at least our feet sink into the sand.
Below is a diagram showing how an increase in pore pressure can push against the sediment particles so that they are not touching any more. This allows the particles to move around and this is why our feet sink in the sand in the analogy above. This is also what changes the strength of earth materials such that a landslide can be triggered.
Below is a diagram based upon a publication designed to educate the public about landslides and the processes that trigger them (USGS, 2004). Additional background information about landslide types can be found in Highland et al. (2008). There was a variety of landslide types that can be observed surrounding the earthquake region. So, this illustration can help people when they observing the landscape response to the earthquake whether they are using aerial imagery, photos in newspaper or website articles, or videos on social media. Will you be able to locate a landslide scarp or the toe of a landslide? This figure shows a rotational landslide, one where the land rotates along a curvilinear failure surface.
Seismic Hazard and Seismic Risk
Human Impact
Some Relevant Discussion and Figures
volcanites; 5: Pieniny Klippen Belt; 6: strike-slip faults; 7: normal faults; 8: thrust faults.
Europe
General Overview
Earthquake Reports
Social Media
Focal mechanism from GFZ Geofon (https://t.co/6E9hLx3oaI), both planes are considered.
*on a lake*
*inside a church*
*on a street with bricks toppling*
*across from a damaged barn crumbling*
and … on a cooking show?https://t.co/TvihBKsdov
EQ Intensity exceed MMI 8
Petrinja, Croatia – one day after a destructive and deadly earthquake.#CroatiaEarthquake
📷 Antonio Bronic pic.twitter.com/aNzfueKWO1
Petrinja, Croatia 🇭🇷
Local time 12:19:54 2020-12-29
Earthquake caught on live camera during interview about earthquakes at Trending Views
potential magnitudes from eg https://t.co/4Agp4cBnrz
[Data source @EMSC; elaborations @robBaras] pic.twitter.com/VOMpUKCevx
Temporal evolution of the foreshock and aftershock sequences associated with last week's magnitude 6.4 Croatia earthquake. pic.twitter.com/F68nSP4QOg
🔗 https://t.co/4JoOJLRoIm — #earthquake #grading in #Croatia#Copernicus #CEMS #RapidMapping #EUCivPro
References:
Basic & General References
Specific References
earthquake and its strongest aftershock of 24 May 1979 (Mw 6.2) in Tectonophysics, v. 421, p. 129-143, http://dx.doi.org/10.1016/j.tecto.2006.04.009Return to the Earthquake Reports page.
Earthquake Report: Owens Valley, CA
https://earthquake.usgs.gov/earthquakes/eventpage/ci39493944/executive
The plate tectonics in the western US is overwhelmingly dominated by the plate boundary between the North America and Pacific plate. The North America plate moves south “relative” to the Pacific plate. Standing on the Pacific plate, looking across the fault, the North America plate moves to your right (a right-lateral strike-slip fault).
Here, both plates are moving “absolutely” in the northwestern direction, but the Pacific plate is moving slower. Therefore the relative sense of motion results in a right-lateral fault.
The plates move side-by-side at a velocity (speed) of about 50 mm per year (2 inches per year). In California, most of this relative motion is localized along the San Andreas fault system. But there are sub-parallel “sibling” faults that also share some of the “slip budget” (their proportion of the 50 mm/yr).
About 20% of the relative plate motion is found along faults on the east side of the Sierra Nevada, along the Eastern California Shear Zone and the Walker Lane system.
Further to the north, in northern California, Oregon, Washington, and Canada, the relative plate motion is compressive, forming the Cascadia subduction zone.
East of California, the plate boundary experiences relative extension, forming the geomorphic province called the Basin and Range. The faults in the Basin and Range are mostly normal faults (extensional faults).
Read more about the different fault types here.
On 26 March 1872 there was a large earthquake that ruptured faults from south of Owens Lake near Olancha, CA northwards to Big Pine, CA. This earthquake may be the largest historic earthquake in California with a magnitude of M 7.8 to 7.9 (Hough and Hutton, 2008).
This earthquake was the result of slip on the Owens Valley fault system (OVF). The majority of slip was right-lateral strike-slip, but because the OVF is not perfectly aligned with the relative plate motion, some of the slip on these faults was normal slip (i.e. extensional).
There are still preserved remains of structures damaged by the earthquake in Lone Pine, CA.
The OVF has been mapped and trenched across to learn about the prehistoric record of earthquakes on the fault.
Also, from measurements of features that have been offset along the fault during earthquakes, along with knowledge of the age of those features, we can estimate how fast the frust is moving relatively across the fault. Below are some figures that help us learn about this historty and activity of the OVF (e.g. Bacon and Pezzopane, 2007; Kirby et al, 2008; Haddon et al., 2013; Bacon et al., 2019).
Beth Haddon et al. (2013) conducted a very interesting study that compiled and updated previous slip estimates for the 1872 OVF earthquake. Their analysis vastly improved the estimate of how much the fault slipped at different locations along the fault (i.e. the fault slip distribution) and included a novel way to account for uncertainty (a.k.a. error) in the measurements of these offsets.
California Geological Survey Engineering Geologist Brian Olson was sent to the field to make observations of fault rupture, landslides, and liquefaction related to this earthquake. Some of his tweets from the field are included below in the social media section.Below is my interpretive poster for this earthquake
I include some inset figures. Some of the same figures are located in different places on the larger scale map below.
I include some inset figures. Some of the same figures are located in different places on the larger scale map below.
Earthquake Triggered Landslides and Liquefaction
Other Report Pages
Some Relevant Discussion and Figures
Geology, 2000; Peltzer et al., 2001), and Owens Valley (Beanland and Clark, 1994; only southern half of rupture is shown) earthquakes. Black dots and arrows show locations and observed velocities of 11 stations of Yucca GPS array (Gan et al., 2000).
* Faults are listed in the paper
RTR—Radio Tower Range, SOM—Southern Owlshead Mountains, WWFZ—WingateWash fault zone, BMF—Brown Mountain fault, OLF—Owl Lake fault, GF—Garlock fault, MSS—Mule Springs strand, LLZ—Leach Lake fault zone, SDVFZ—Southern Death Valley fault zone.
Background Literature – Geodesy
*See their paper for fault abbreviations.
Color of rupture segment represents ratio of time since last earthquake and recurrence interval. Hot (red) colors show segments are in early earthquake cycle, and cold (blue) colors show late earthquake cycle.
Creek fault zone; FLV— Fish Lake Valley fault zone.
Background Literature – Owens Valley fault
(B) Generalized fault and geology map of south-central Owens Valley, showing the A.D. 1872 Owens Valley fault rupture and major fault zones in the valley (modified from Hollett et al. [1991] and Beanland and Clark [1994]).
(For fault abbreviations, see their paper.)
paleoseismic relations exposed in adjacent fault trenches and stratigraphic pits). The locations of sequence boundaries (SB0–SB4) are shown and can be referenced on Figure 5.
fault plane striking 3408 and dipping 808 northeast. The maximum implied displacement is between 7 and 11 m and reflects the average of four high values. The net slip averages 4.461.5 m based on a 5-km binned average that incorporates graphical values for gaps between higher confidence data.
Background Literature – Earthquake History
San Andreas plate boundary
General Overview
Earthquake Reports
Northern CA
Central CA
Southern CA
Social Media
prob (?) not aftershock from 1872 M7.8-9 OVF EQhttps://t.co/Ux1s5W1Dph pic.twitter.com/KY22aJLFU4
Thanks to the seismic records provided by NCEDC, SCEC, and IRIS pic.twitter.com/wO6bKkbxwx
Sentinel Path 144 (2020.06.21-2020.06.27)
v1:
Centroid lon/lat:-117.975/ 36.488
Centroid depth (km): 13.24
Depth range (km): 7.98-18.5
Geodetic Mag: Mw5.8
Slip mag (m): 0.297
Str/Dip/Rake: 339/67/132
Len/Wid (km): 5.67/11.40 pic.twitter.com/qw3Ovjp1bO
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report: Banda Sea
https://earthquake.usgs.gov/earthquakes/eventpage/us70009b14/executive
This earthquake was a strike-slip earthquake in the Australia plate. There are analogical earthquakes in the same area in 1963, 1987, 2005, and 2012 that appear to have occurred on the same fault.
In June 2019 there was an earthquake nearby with a similar mechanism.Below is my interpretive poster for this earthquake
Global Strain
I include some inset figures. Some of the same figures are located in different places on the larger scale map below.
Other Report Pages
Some Relevant Discussion and Figures
Seismic Hazard and Seismic Risk
Indonesia | Sumatra
General Overview
Earthquake Reports
Social Media
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report: Idaho!
Yesterday there was a very interesting magnitude M 6.5 earthquake that ruptured in central Idaho, near the Sawtooth fault.
The M 6.5 earthquake yesterday happened in an area where a Basin & Range (B&R) fault ends near one of these older Eocene aged faults. Most of us saw the earthquake notification and probably thought that the quake would have been a B&R normal (extensional) fault. However, when the mechanism was posted online, the earthquake mechanism was instead a strike-slip earthquake. This was really interesting. I love when things happen that are unexpected. This is what makes life exciting.
Thanks to the Idaho Geological Survey, I learned of some of the faults in the region. I downloaded their geologic maps and GIS data and started to work.
Dr. Thackray used newly collected high resolution LiDAR topographic data to identify fault scarps that offset geomorphic features that during Holocene time. If the landforms were created less than 12,000 years ago and the fault cut through these landforms, then the earthquake that cut the landforms happened after the landforms were created (and also less than 12,000 years ago).
OK, lets look at some eye candy. (sorry for the long introduction)Below is my interpretive poster for this earthquake
I include some inset figures. Some of the same figures are located in different places on the larger scale map below.
Earthquake Triggered Landslides
If we look at the map at the top of this report, we might imagine that because the areas close to the fault shake more strongly, there may be more landslides in those areas. This is probably true at first order, but the variation in material properties and water content also control where landslides might occur.
Other Report Pages
Some Relevant Discussion and Figures
Springs section, prehistoric ruptures PE2 (magenta) and PE1 (blue) show significantly more displacement than the 1983 rupture (red). Green line shows prehistoric VS along the Arentson Gulch fault. Gray box shows extent of the Willow Creek Hills structure along the Lost River fault zone. Triangles show paleoseismic sites. SC—Sheep Creek; DP—Doublespring Pass.
Basin and Range
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Utah
Idaho
Nevada
Social Media
cf. fault maps https://t.co/d28LmscgnFhttps://t.co/HI9CvkxAwshttps://t.co/P3jEoJ2KLM pic.twitter.com/i6IYXgS9xE
Full report in the link below: https://t.co/30Jpx70s0g
UPDATE 2020.04.05
References:
Basic & General References
Specific References
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Earthquake Report: Mendocino triple junction
In the past 9 months it was also a big mag 5 MTJ year. There have been 3 mag 5+ earthquakes in the Mendocino triple junction (MTJ) region. The first one in June of 2019, at the time, appeared to be related to the Mendocino fault. The 9 March M 5.8 event was clearly associated with the right lateral Mendocino transform fault. The latest in this series of unrelated earthquakes is possibly associated with NW striking faults in the Gorda plate. I will discuss this below and include background about all the different faults in the region.
My social media feed was immediately dominated by posts about the earthquake in Humboldt County. I put together a quick map (see below). My good friend and collaborator Bob McPherson (a seismologist who ran the Humboldt Bay Seismic Network in the late 70s and 80s) sent me several text messages about the earthquake. we texted back and forth. I initially thought it might be Mendo fault and so did he.
Then the USGS moment tensor (earthquake mechanism) came in with an orientation similar to that of Gorda plate earthquakes further to the north. These earthquakes are typically on northeast striking (trending) left-lateral strike-slip faults (see more here about types of earthquakes). So, I stated that I thought it was like those, a left-lateral strike-slip fault earthquake. So I deleted my social media posts and updated the map to show it could be either left-lateral or right-lateral (the map below shows both options), but that we thought it was in the Gorda plate, not the Mendocino fault.
Then Bomac mentioned these northwest trends in seismicity that we noticed (as a group) about 5 years ago, seismicity trends (seismolineaments is what Tom calls them) that first appeared following the 1992 Cape Mendocino Earthquake.
We don’t yet have a full explanation for these trends in seismicity, but the orientation fits a stress field from north-south compression (from the northward motion of the Pacific plate relative to the Gorda plate). This north-south compression is also the explanation for the left-lateral strike-slip fault earthquakes in the Gorda plate (Silver, 1971).How are these 3 M5+ MTJ events related?
WHy?
Well, there are two kinds of earthquake triggering.
* note, i corrected this caption by changing the word “relationships” to “relations.”
The M 5.6 might have a rupture length crudely about 3 km might affect the region up to 9 km away. The M 5.2 is ~16 km from the M 5.6, so probably too far to be affected.
However, these earthquakes are related because they are all in the same region and are responding to the same tectonic forces.Below is my interpretive poster for this earthquake
I include some inset figures. Some of the same figures are located in different places on the larger scale map below.
There is a nice northeast trend in seismicity that I also outlined. This is probably representative of one of the typical left-lateral Strike-slip Gorda plate earthquakes.Other Report Pages
Some Relevant Discussion and Figures
I have compiled some literature about the CSZ earthquake and tsunami. Here is a short list that might help us learn about what is contained within the core that I collected.
These two quakes appear to be aligned with the two northwest trends in seismicity and the 18 March 2020 M 5.2. The orientation of the mechanisms are not as perfectly well aligned, but there are lots of reasons for this (perhaps the faults were formed in a slightly different orientation, but have rotated slightly).
There have been several series of intra-plate earthquakes in the Gorda plate. Two main shocks that I plot of this type of earthquake are the 1980 (Mw 7.2) and 2005 (Mw 7.2) earthquakes. I place orange lines approximately where the faults are that ruptured in 1980 and 2005. These are also plotted in the Rollins and Stein (2010) figure above. The Gorda plate is being deformed due to compression between the Pacific plate to the south and the Juan de Fuca plate to the north. Due to this north-south compression, the plate is deforming internally so that normal faults that formed at the spreading center (the Gorda Rise) are reactivated as left-lateral strike-slip faults. In 2014, there was another swarm of left-lateral earthquakes in the Gorda plate. I posted some material about the Gorda plate setting on this page.
Further North
If we turn our head at an oblique angle, we may consider the San Andreas, the Mendocino, and the Blanco faults to be all part of the same transform fault.
Transform faults are often (or solely) defined as a strike-slip fault system that terminates at each end with a spreading ridge. These 3 systems link spreading ridges in the Gulf of California, through the Gorda Rise, to the Juan de Fuca ridge (and further).
The Blanco fault is as, or more active than the Mendocino fault. The excellent people in Oregon who are aware of their exposure to seismic and tsunami hazards from the Cascadia subduction zone are always interested when there are earthquake notifications.
Earthquakes on the Blanco fault are some of these events that people notice and ask about, “should I be concerned?” The answer is generally, “those earthquakes are too far away and too small to change the chance of the “Big One.” (remember the discussion about dynamic triggering above?)
There was a recent earthquake (2018) on the Blanco fault that brought the public to question this again. My report about that earthquake spent a little space addressing these fault length >> magnitude >> triggering issues.
As we know, the tectonics of the northeast Pacific is dominated by the Cascadia subduction zone, a convergent plate boundary, where the Explorer, Juan de Fuca, and Gorda oceanic plates dive eastward beneath the North America plate.
These oceanic plates are created (formed, though I love writing “created” in science writing) at oceanic spreading ridges/centers.
When oceanic spreading centers are offset laterally, a strike-slip fault forms called a transform fault. The Blanco transform fault is a right-lateral strike-slip fault (like the San Andreas fault). Thanks to Dr. Harold Tobin for pointing out why this is not a fracture zone.
The main take away is that we are not at a greater risk because of these earthquakes.
Cascadia subduction zone
General Overview
Earthquake Reports
Gorda plate
Blanco transform fault
Mendocino fault
Mendocino triple junction
North America plate
Explorer plate
Uncertain
Social Media
References:
Basic & General References
Specific References
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