There was a damaging earthquake in Turkey yesterday, a magnitude M 6.1.
https://earthquake.usgs.gov/earthquakes/eventpage/us7000irp8/executive
The seismic hazards of this region of the Earth is dominated by a plate boundary fault, the North Anatolia fault (NAF).
The NAF is a right-lateral strike-slip earthquake fault that has a slip rate of about 24 mm/yr. This fault is similar in fault type and slip rate to the San Andreas fault in California.
There have been a series of large earthquakes along the NAF in the 20th century. See the poster below that highlights the 1999 M 7.6 Izmit Earthquake.
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 left corner is a map that shows the tectonic strain in the region. Areas of red are deforming more from tectonic motion than are areas that are blue. Learn more about the Global Strain Rate Map project here.
- In the upper right corner is a comparison of the shaking intensity modeled by the USGS and the shaking intensity based on peoples’ “boots on the ground” observations. The closer to the earthquake, the stronger the ground shaking. A modeled estimate of intensity is shown by the color overlay and labels MMI 4, 5, 6, 7. The USGS Did You Feel It observations are the colored circles (color = intensity) and labeled dyfi 6.2 for example.
- Below the strain map 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).
- To the left of the intensity map is a tectonic map from Taymaz et al., 2007 that shows the main plate boundary faults and their relative senses of motion.
- To the left of the tectonic map is a plot from Stein et al. (1997) that shows the slip from these 20th century earthquakes along the NAF.
- To the left of the Stein figure are two histograms from the USGS PAGER Alert system. These are rapid estimates of the potential damage from this earthquake. These data help organizations understand what response programs need to be utilized to help the people in this region following this earthquake.
- In the center right is a map from the Seismic Hazard Harmonization in Europe program, which shows the chance for ground shaking from earthquakes over the next 50 years.
- In the lower right corner is a larger scale map showing the tectonic geomorphology of the region (how the landscape is sculpted by tectonic forces). This map has aftershocks from the CSEM-EMSC catalog.
- 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 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
- This is the plate tectonic map from Armijo et al., 1999.
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.
- Here is the tectonic map from Dilek and Sandvol (2009).
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).
- 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.
- This is a fantastic figure, yet quite complicated. This map shows teh plate boundaries, the GPS motions, and the tectonic strain for the region (Perouse et al., 2012).
- We use GPS sites at specific locations to measure how fast the Earth’s crust moves due to plate tectonics and other reasons. These GPS sites are almost constantly recording their geographic position. If a GPS site is moving, we can take two observations (lets say a year apart), measure their relative distance, and divide the time between the measurements to get the velocity (the speed) that this GPS site is moving. The white vectors (the arrows) show the direction those GPS sites are moving and the length of the vector represents its velocity. The black arrows show what the plate motion rates are at the plate boundaries and these are modeled using lots of different data sources (not just GPS).
- Tectonic strain is a measure of how much the Earth’s crust is deforming over time. The higher the tectonic strain rate (i.e. red), the more tectonic stress is being accumulated in the crust and along faults. Areas of higher strain are places where there are more likely to be larger or more (or both) earthquakes.
Present-day kinematic and tectonic map encompassing the Central and Eastern Mediterranean, summarizing our main results and interpretations. Our kinematic model includes rigid-block motions as well as localized and distributed strain. Central-SW Aegean block (CSW AEG block) and East Anatolian block (East Anat. block) are purely kinematic and directly results from strain modeling (Figure 5). AP-IO Block is our Apulian-Ionian block with tentative tectonic boundaries. Rotation pole of this Apulian-Ionian block relative to Nubia (Nu WAp-Io) and to Eurasia (Eu WAp-Io) are shown with their 95% confidence ellipse.
- 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.
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.
- Here is a map showing tectonic domains (Taymaz et al., 2007).
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.
- Because this 1999 earthquake is important for many reasons, I will be writing up an Earthquake Report for that event sometime soon. In the meantime, here is a poster I put together for that event.
- Of particular note is that this August earthquake generated a small tsunami. I use this in my tsunami talks to highlight how there are non-traditional tsunami sources that need to be considered when mitigating tsunami hazards. Even though this tsunami was only a couple meters high, that is enough to damage harbors, boats, and people.
- 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 6.1 earthquake.
- For the first time, I include maps that show the uncertainty in these ground failure models. The larger the uncertainty is shown in red and the lower the uncertainty is shown in blue. I cut off the symbology at 0.1%.
Earthquake Triggered Landslides
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.
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).
- 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
#EarthquakeReport for M6.1 #Deprem #Earthquake in northern #Turkey
probably a right-lateral strike-slip earthquake along the North Anatolia fault system
strong shaking in the Düzce region, close to the 1999 M7.2 temblor
read more in the report herehttps://t.co/7rNAKb3zJu pic.twitter.com/juJlK2L1WM
— Jason "Jay" R. Patton (@patton_cascadia) November 24, 2022
Early morning, Nov. 23 local time, a magnitude 6.1 earthquake occurred 16 km (10 mi) west of Düzce, Turkey. This event is currently at PAGER level orange, indicating significant damage is likely & the disaster is potentially widespread. Our thoughts are with the people of Düzce. https://t.co/0fRUHHnnaS pic.twitter.com/CG2DuWfOfK
— USGS Earthquakes (@USGS_Quakes) November 23, 2022
⚠️ Confirmed: Real-time network data show a significant disruption to internet connectivity in #Düzce, #Turkey following a 5.9 magnitude earthquake; the outages are attributed to widespread power cuts reported in the region 📉 pic.twitter.com/88Wi87Am4i
— NetBlocks (@netblocks) November 23, 2022
Also playing in to this is the Baader-Meinhof phenomenon, also known as the frequency illusion. https://t.co/yWLqZIoN8b
— Wendy Bohon, PhD 🌏 (@DrWendyRocks) November 23, 2022
The region has already a lot of landslides. Triggering will depend on H2O saturation. The NAF also created quite a lot of pull apart basins which are prone to liquefaction, especially around Golyaka
— Oz ⚒️ (@OzgurKozaci) November 23, 2022
It looks like side faulde of main North Anatolian Fault
At 11/1999 we had major earthquake (7.2Mw) on the NAF segment
08/1999 (7.6Mw) Marmara earthquake had struck southern bold red higlihted faultToday's tremble was felt over a vast area from western istanbul to ankara pic.twitter.com/RUaU9qKLus
— Emre Evren (@EmreEvren_IYI) November 23, 2022
#Latest 5.9 Mw (#KRDAE) Northern #TURKEY 🇹🇷, a shallow right-lateral strike-slip (Karadere-Düzce Branch/North Anatolian Fault System), possible severe damage in nearby localities, figure from Roux/Ben-Zion et al. 2014. pic.twitter.com/0JGFmoKgfa
— Abel Seism🌏Sánchez (@EQuake_Analysis) November 23, 2022
Mw=6.1, TURKEY (Depth: 12 km), 2022/11/23 01:08:14 UTC – Full details here: https://t.co/IMFvc2js15 pic.twitter.com/PJ2MJMlpKS
— Earthquakes (@geoscope_ipgp) November 23, 2022
Düzce'de #deprem anı… pic.twitter.com/zfjsy7j17T
— İzzet Altaş (@izzetaltas_) November 23, 2022
Updated source mechanism of 2022.11.23 Mw6.0 Düzce Earthquake. Green lines=Broken parts of the NAF(Konca et al., 2010; Bouchon et al., 2002). Red line=Unbroken part of Karadere Segment. LowerPanel:Coulomb stress change (Location:@Kandilli_info) pic.twitter.com/GthYfz9ElY
— Sezim (@sezim_guvercin) November 23, 2022
In 1999 the North Anatolian Fault (NAF), broke during two destructive #earthquakes (Mw7.4 Izmit and Mw7.2 Düzce). Today's Mw6.1 #earthquake happened east of Düzce with mechanism similar to 2019 event.
Mechanism https://t.co/dKXlLfRKkt
and 1999 rupture map https://t.co/rWvuOEAIPo pic.twitter.com/sSyFd5SmGj— Robin Lacassin – @RobinLacassin@qoto.org (@RLacassin) November 23, 2022
Manually revised solution FMNEAR (Géoazur/OCA) with regional records for the M 6.1 – WESTERN TURKEY – 2022-11-23 01:08:15 UTC (Loc KOERI used).https://t.co/UHDsc1hVXA
Thanks to the seismic records provided in particular by KOERI and IRIS pic.twitter.com/3unR3l5aAZ
— Bertrand Delouis (@BertrandDelouis) November 23, 2022
📌 A brief information about Gölyaka (Düzce) Earthquake (Mw=5.9)
Date: 23.11.2022
Time: 04:08 (Local Time)#Earthquake #Duzceearthquake@LastQuake @ISCseism pic.twitter.com/T5xXRqpnIH— AFAD Deprem (@DepremDairesi) November 23, 2022
Düzce de bir iş yerinin güvenlik kamerasına yansıyam görüntüler çok korkunç rabbim beterinden korusun #deprem pic.twitter.com/Qm7zgygaY1
— Ozan Aydoğdu (@OzyAydogdu) November 23, 2022
23 Kasım 2022 #Düzce-Gölyaka depreminin (Mw=6.0) 230km uzaklıktaki Marmara Denizi'nde 23yıl geçmesine karşın, henüz gerçekleşmeyen beklenen olası #deprem'i etkilemesi söz konusu değildir. Böyle bir bağlantı kurabilecek/ispatlayacak bölgesel bir stres haritası bile sunamazsınız. pic.twitter.com/yWAC3uKHjS
— Dr. Ramazan Demirtaş (@Paleosismolog) November 23, 2022
Interesting @NERC_COMET 2020 webinar from Dr Jonathan Weiss & Dr Chris Rollins.
Great use of @CopernicusEU #Sentinel1 to help resolve strain rate, & earthquake hazards, in Anatolia. Shows why Mag 5.9 earthquakes, like Duzce, should come as no surprise.https://t.co/UaobvrrHXS pic.twitter.com/jyCFstX9rX
— DPManchee (@DPManchee) November 24, 2022
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- DISS Working Group (2015). Database of Individual Seismogenic Sources (DISS), Version 3.2.0: A compilation of potential sources for earthquakes larger than M 5.5 in Italy and surrounding areas. http://diss.rm.ingv.it/diss/, Istituto Nazionale di Geofisica e Vulcanologia; DOI:10.6092/INGV.IT-DISS3.2.0.
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- Ersoy, E.Y., Cemen, I., Helvaci, C., and Billor, Z., 2014. Tectono-stratigraphy of the Neogene basins in Western Turkey: Implications for tectonic evolution of the Aegean Extended Region in Tectonophysics v. 635, p. 33-58.
- Jenkins, Jennifer, Turner, Bethan, Turner, Rebecca, Hayes, G.P., Sinclair, Alison, Davies, Sian, Parker, A.L., Dart, R.L., Tarr, A.C., Villaseñor, Antonio, and Benz, H.M., compilers, 2013, Seismicity of the Earth 1900–2010 Middle East and vicinity (ver 1.1, Jan. 28, 2014): U.S. Geological Survey Open-File Report 2010–1083-K, scale 1:7,000,000, https://pubs.usgs.gov/of/2010/1083/k/.
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- Kaya, A., 2015. The effects of extensional structures on the heat transport mechanism: An example from the Ortakçı geothermal field (Büyük Menderes Graben, SW Turkey) in Journal oF african Easth Sciences, v. 108, p. 74-88, http://dx.doi.org/10.1016/j.jafrearsci.2015.05.002
- Kokkalas, S., et al., 2006. Postcollisional contractional and extensional deformation in the Aegean region in GSA Special Papers, v. 409, p. 97-123.
- Kurt, H., Demirbag, E., and Kuscu, I., 1999. Investigation of the submarine active tectonism in the Gulf of Gokova, southwest Anatolia–southeast Aegean Sea, by multi-channel seismic reflection data in Tectonophysics, v. 305, p. 477-496
- Ocakoglu, N., DEmirbag, E.,. and Kuscu, I., 2005. Neotectonic structures in I˙zmir Gulf and surrounding regions (western Turkey): Evidences of strike-slip faulting with compression in the Aegean extensional regime in Marine Geology, v. 219, p. 155-171, doi:10.1016/j.margeo.2005.06.004
- Papazachos, B.C., Papadimitrious, E.E., Kiratzi, A.A., Papazachos, C.B., and Louvari, E.k., 1998. Fault Plane Solutions in the Aegean Sea and the Surrounding Area and their Tectonic Implication, in Bollettino Di Geofisica Terorica Ed Applicata, v. 39, no. 3, p. 199-218.
- Pérouse, E., N. Chamot-Rooke, A. Rabaute, P. Briole, F. Jouanne, I. Georgiev, and D. Dimitrov, 2012. Bridging onshore and offshore present-day kinematics of central and eastern Mediterranean: Implications for crustal dynamics and mantle flow, Geochem. Geophys. Geosyst., 13, Q09013, doi:10.1029/2012GC004289.
- Rojay, B., Toprak, V., Demirci, C., and Süzen, L., 2005. Plio-Quaternary evolution of the Küçük Menderes Graben Southwestern Anatolia, Turkey in Geodinamica Acta, v. 18, no. 3-4, p. 317-331
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- Wouldloper, 2009. Tectonic map of southern Europe and the Middle East, showing tectonic structures of the western Alpide mountain belt. Only Alpine (tertiary) structures are shown.
References:
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The past couple of weeks have been busy from an earthquake perspective. There have been four M7 events. I am writing this report a few days late. But, better late than never! There was a magnitude M 7.0 earthquake offshore of the Solomon Islands. https://earthquake.usgs.gov/earthquakes/eventpage/us7000irfb/executive The Solomon Islands owe their existence to the plate boundary fault system there, a convergent plate boundary where plates move towards each other. The plate boundary here is formed by the subduction of the Australia plate beneath the Pacific plate. The largest earthquakes that happen on Earth happen on these subduction zone faults. At first I thought that this was an interface earthquake along the megathrust subduction zone fault. These are called interface events because they happen along the fault interface between the two plates. They are also called interplate earthquakes. However, as the earthquake mechanisms (e.g., focal mechanism or moment tensor) were calculated and posted online, it was clear that this was not a megathrust earthquake. Here is an illustration that shows a cross section of a subduction zone. I show hypothetical locations for different types of earthquakes. I include earthquake mechanisms (as they would be viewed from map view) for these different types of earthquakes. Here is a legend for these different mechanisms. We can see what the mechanisms look like from map view (from looking down onto Earth from outer space or from flying in an airplane) and what they look like from the side. The mechanism for the M 7.0 Solomon Isle earthquake is an extensional (normal) type of an earthquake that happened in the slab of the Australia plate. Typically, the extension in these slab events is perpendicular to the plate boundary fault because that is the direction that the plate is pulling down (slab pull) due to gravity or that is the orientation of bending of the plate that causes this extension. In this case, the orientation of extension is oblique (not perpendicular, nor parallel) to the plate boundary. The leading hypothesis for this is that there is some pre-existing structure in the Australia plate that hosted this earthquake fault slip. If we look to the west, to the structures in the Woodlark Basin, we see some candidate structures for this earthquake. These are faults that are related to the seafloor spreading that formed the Woodlark Basin. It is possible that some of these faults have been subducted beneath the Solomon Isles (though this is unclear). There are also records of tsunami and seismic waves on water level sensors in this region. A tsunami was observed on the Honiara tide gage and seismic waves observed on the Coral Sea DART Buoy 55023. Here are the tide gage data from https://webcritech.jrc.ec.europa.eu/SeaLevelsDb/Home. This is a small tsunami that happened on a tide gage with noisy data. So, it is difficult to tell how long the tsunami lasted here. Here are the DART data from the same website. I triple checked the size of the wave but it still seems a little large for a seismic wave. I could still be wrong. Feel free to contact me if you think this plot needs to be corrected! quakejay at gmail.com.
Tectonic setting of Papua New Guinea and Solomon Islands. a) Regional plate boundaries and tectonic elements. Light grey shading illustrates bathymetry b 2000 m below sea level indicative of continental or arc crust, and oceanic plateaus; 1000 m depth contour is also shown. Adelbert Terrane (AT); Bismarck Sea fault (BSF); Bundi fault zone (BFZ); Feni Deep (FD); Finisterre Terrane (FT); Gazelle Peninsula (GP); Kia-Kaipito-Korigole fault zone (KKKF); Lagaip fault zone (LFZ); Mamberamo thrust belt (MTB); Manus Island (MI); New Britain (NB); New Ireland (NI); North Sepik arc (NSA); Ramu-Markham fault (RMF); Weitin Fault (WF);West Bismarck fault (WBF); Willaumez-Manus Rise (WMR).
a) Present day tectonic features of the Papua New Guinea and Solomon Islands region as shown in plate reconstructions. Sea floor magnetic anomalies are shown for the Caroline plate (Gaina and Müller, 2007), Solomon Sea plate (Gaina and Müller, 2007) and Coral Sea (Weissel and Watts, 1979). Outline of the reconstructed Solomon Sea slab (SSP) and Vanuatu slab (VS)models are as indicated. b) Cross-sections related to the present day tectonic setting. Section locations are as indicated. Bismarck Sea fault (BSF); Feni Deep (FD); Louisiade Plateau
While I was travelling back from a USGS Powell Center Workshop on the recurrence of earthquakes along the Cascadia subduction zone, there was an earthquake (gempa) offshore of Sumatra. https://earthquake.usgs.gov/earthquakes/eventpage/us7000iqpn/executive There was actually a foreshock (more than one): https://earthquake.usgs.gov/earthquakes/eventpage/us7000iq2d/executive OK, sunset led to nap, led to bed. The plate boundary offshore of Sumatra, Indonesia, is a convergent (moving together) plate boundary. Here, the Australia plate subducts northwards beneath the Sunda plate (part of the Eurasia plate) along a megathrust subduction zone fault. This subduction forms a deep sea trench, the Sunda trench. This was a shallow event near the trench formed by the subduction here. The magnitude was a little small for generating a large tsunami. However, it was shallow, so the deformation reached the sea floor and generated tsunami recorded on several tide gages in the region. These gages are operated by the Indonesian Geospatial Reference System, though there are some gages that are posted on the European Union World Sea Levels website. The water surface elevation data was a little noisy on these tide gage plots, but two of them had sufficient signal to justify my interpretation that these are tsunami. My interpretations could be incorrect and I include two plots below. Many are familiar with the Boxing Day Earthquake and Tsunami from December 2004. This is one of the most deadly events in modern history, almost a quarter million people perished (mostly from the tsunami). These lives lost did lead to changes in how tsunami risk is managed worldwide. So, these lives lost were not lost in vain (though it would be better if they were not lost, we can all agree to that). The southern Sumatra subduction zone has an excellent record of prehistoric and historic earthquakes. For example, there is a couplet where earthquake slips overlapped slightly, the 1797 and 1833 earthquakes. Many think that this area is the next place a large tsunamigenic earthquake may occur. Below we can see the analysis from Chlieh et al. (2008) where they suggest that there is considerable tectonic strain accumulated since these 1797 and 1833 earthquakes. There have been several large earthquakes in this area but they may not have released this strain. If we look at the Chlieh et al. (2008) study, we will notice that this M 6.9 earthquake happened in an area thought to be in an area that is not accumulating much tectonic strain. I post a figure showing this later in the report. There are millions of people who live in the coastal lowlands of Padang who may have difficulty evacuating in time should an earthquake like the 2004 Sumatra-Andaman subduction zone earthquake were to occur in this area. For those that live along the coast here, the ground shaking from the earthquake is their natural notification to evacuate to high ground. For those that live across the ocean, they will get warning notifications to help them learn to evacuate since they won’t have the ground shaking as a warning. This is what happened to many people in December 2004 along the east coast of India and along the coast of Sri Lanka. Here are some of the larger historic earthquakes in this area, ordered by magnitude:
Sumatra core location and plate setting map with sedimentary and erosive systems figure. A. 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). B. Schematic illustration of geomorphic elements of subduction zone trench and slope sedimentary settings. Submarine channels, submarine canyons, dune fields and sediment waves, abyssal plain, trench axis, plunge pool, apron fans, and apron fan channels are labeled here. Modified from Patton et al. (2013 a).
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.
Recent and ancient ruptures along the Mentawai section of the Sunda megathrust. Colored patches are surface projections of 1-m slip contours of the deep megathrust ruptures on 12–13 September 2007 (pink to red) and the shallow rupture on 25 October 2010 (green). Dashed rectangles indicate roughly the sections that ruptured in 1797 and 1833. Ancient ruptures are adapted from Natawidjaja et al. [2006] and recent ones come from Konca et al. [2008] and Hill et al. (submitted manuscript, 2012). Labeled points indicate coral study sites Sikici (SKC), Pasapuat (PSP), Simanganya (SMY), Pulau Pasir (PSR), and Bulasat (BLS).
Distribution of coupling on the Sumatra megathrust derived from the formal inversion of the coral and of the GPS data (Tables 2, 3, and 4) prior to the 2004 Sumatra-Andaman earthquake (model I-a in Table 7). (a) Distribution of coupling on the megathrust. Fully coupled areas are red, and fully creeping areas are white. Three strongly coupled patches are revealed beneath Nias island, Siberut island, and Pagai island. The annual moment deficit rate corresponding to that model is 4.0 X 10^20 N m/a. (b) Observed (black vectors) and predicted (red vectors) horizontal velocities appear. Observed and predicted vertical displacements are shown by color-coded large and small circles, respectively. The Xr^2 of this model is 3.9 (Table 7).
Distribution of coupling on the Sumatra megathrust derived from the formal inversion of the horizontal velocities and uplift rates derived from the CGPS measurements at the SuGAr stations (processed at SOPAC). To reduce the influence of postseismic deformation caused by the March 2005 Nias-Simeulue rupture, velocities were determined for the period between June 2005 and October 2006. (a) Distribution of coupling on the megathrust. Fully coupled areas are red and fully creeping areas are white. This model reveals strong coupling beneath the Mentawai Islands (Siberut, Sipora, and Pagai islands), offshore Padang city, and suggests that the megathrust south of Bengkulu city is creeping at the plate velocity. (b) Comparison of observed (green) and predicted (red) velocities. The Xr^2 associated to that model is 24.5 (Table 8).
Distribution of coupling on the Sumatra megathrust derived from the formal inversion of all the data (model J-a, Table 8). (a) Distribution of coupling on the megathrust. Fully coupled areas are red, and fully creeping areas are white. This model shows strong coupling beneath Nias island and beneath the Mentawai (Siberut, Sipora and Pagai) islands. The rate of accumulation of moment deficit is 4.5 X 10^20 N m/a. (b) Comparison of observed (black arrows for pre-2004 Sumatra-Andaman earthquake and green arrows for post-2005 Nias earthquake) and predicted velocities (in red). Observed and predicted vertical displacements are shown by color-coded large and small circles (for the corals) and large and small diamonds (for the CGPS), respectively. The Xr^2 of this model is 12.8.
Comparison of interseismic coupling along the megathrust with the rupture areas of the great 1797, 1833, and 2005 earthquakes. The southernmost rupture area of the 2004 Sumatra-Andaman earthquake lies north of our study area and is shown only for reference. Epicenters of the 2007 Mw 8.4 and Mw 7.9 earthquakes are also shown for reference. (a) Geometry of the locked fault zone corresponding to forward model F-f (Figure 6c). Below the Batu Islands, where coupling occurs in a narrow band, the largest earthquake for the past 260 years has been a Mw 7.7 in 1935 [Natawidjaja et al., 2004; Rivera et al., 2002]. The wide zones of coupling, beneath Nias, Siberut, and Pagai islands, coincide well with the source of great earthquakes (Mw > 8.5) in 2005 from Konca et al. [2007] and in 1797 and 1833 from Natawidjaja et al. [2006]. The narrow locked patch beneath the Batu islands lies above the subducting fossil Investigator Fracture Zone. (b) Distribution of interseismic coupling corresponding to inverse model J-a (Figure 10). The coincidence of the high coupling area (orange-red dots) with the region of high coseismic slip during the 2005 Nias-Simeulue earthquake suggests that strongly coupled patches during interseismic correspond to seismic asperities during megathrust ruptures. The source regions of the 1797 and 1833 ruptures also correlate well with patches that are highly coupled beneath Siberut, Sipora, and Pagai islands.
Latitudinal distributions of seismic moment released by great historical earthquakes and of accumulated deficit of moment due to interseismic locking of the plate interface. Values represent integrals over half a degree of latitude. Accumulated interseismic deficits since 1797, 1833, and 1861 are based on (a) model F-f and (b) model J-a. Seismic moments for the 1797 and 1833 Mentawai earthquakes are estimated based on the work by Natawidjaja et al. [2006], the 2005 Nias-Simeulue earthquake is taken from Konca et al. [2007], and the 2004 Sumatra-Andaman earthquake is taken from Chlieh et al. [2007]. Postseismic moments released in the month that follows the 2004 earthquake and in the 11 months that follows the Nias-Simeulue 2005 earthquake are shown in red and green, respectively, based on the work by Chlieh et al. [2007] and Hsu et al. [2006].
Free-air gravity anomaly map derived from satellite altimetry [Sandwell and Smith, 2009] over the Wharton Basin area.
Structure and age of the Wharton Basin deduced from free-air gravity anomaly [Sandwell and Smith, 2009; background colors] for the fracture zones (thin black longitudinal lines), and marine magnetic anomaly profiles (not shown) for the isochrons (thin black latitudinal lines). The plain colors represent the oceanic lithosphere created during normal geomagnetic polarity intervals (see legend for the ages of Chrons 20 to 34 according to the time scale of Gradstein et al. [2004]). Compartments separated by major fracture zones are labeled A to H. Grey areas: oceanic plateaus, thick black line: Sunda Trench subduction zone.
Reconstitution of the subducted magnetic isochrons and fracture zones of the northern Wharton Basin using the finite rotation parameters deduced from our two- and three-plate reconstructions. (a) First the geometry is restored on the Earth surface, then (b) it is draped on the top of the subducting plate as derived from seismic tomography [Pesicek et al., 2010] shown by the thin dotted lines at intervals of 100 km (b). Colored dots: identified magnetic anomalies; colored triangles: rotated magnetic anomalies, solid lines; observed fracture zones and isochrons, dashed lines: uncertain or reconstructed fracture zones, dotted lines: reconstructed isochrons from rotated magnetic anomalies (two-plate and three-plate reconstructions), colored area: oceanic lithosphere created during normal geomagnetic polarity intervals (see legend for the ages; the colored areas without solid or dotted lines have been interpolated), grey areas: oceanic plateaus, thick line: Sunda Trench subduction zone.
The deviation of the Sunda Trench from a regular arc shape (dotted lines) off Sumatra is explained by the presence of the younger, hotter and therefore lighter lithosphere in compartments C–F, which resists subduction and form an indentor (solid line). The very young compartment G was probably part of this indentor before oceanic crust formed at slow spreading rate near the Wharton fossil spreading center approached subduction: The weaker rheology of outcropping or shallow serpentinite may have favored the restoration of the accretionary prism in this area. Further south, the deviation off Java is explained by the resistance of the thicker Roo Rise, an oceanic plateau entering the subduction.
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 M6.9 #Gempa #Earthquake offshore of #Sumatra #Indonesia Appears to be on the megathrust subduction zone fault Read more about the regional tectonics herehttps://t.co/sjXP2RmtVuhttps://t.co/bglPVLQUDt pic.twitter.com/KSdUDVh9HD — Jason "Jay" R. Patton (@patton_cascadia) November 18, 2022 #EarthquakeReport for M 6.9 #Gempa #Earthquake offshore of #Sumatra #Indonesia appears to be a megathrust subduction zone fault earthquake generated a small tsunami recorded on tide gages read more here:https://t.co/KKizpqJuSa pic.twitter.com/W4gCCJ9bKY — Jason "Jay" R. Patton (@patton_cascadia) November 20, 2022 #EarthquakeReport for M 6.9 #Gempa #Earthquake offshore of #Sumatra #Indonesia probably slip along megathrust subduction zone where Chlieh modeled low seismogenic coupling https://t.co/nuGY5m9iGD *in area absent of GPS/microatoll data read more here:https://t.co/KKizpqsrQa pic.twitter.com/oZP5u7JgiK — Jason "Jay" R. Patton (@patton_cascadia) November 20, 2022 #EarthquakeReport #TsunamiReport for M 6.9 #Gempa #Earthquake offshore of #Sumatra #Indonesia Cocos Isle gage updated due to twitter peer review from @Harold_Tobin thanks! also added Bintuhan record interp poster and plots updated in report herehttps://t.co/KKizpqsrQa pic.twitter.com/TGgCZeA1MV — Jason "Jay" R. Patton (@patton_cascadia) November 20, 2022 Effects of the magnitude 6.9 #earthquake off #Sumatra #Indonesia was felt in my apartment over 776 km away in #Singapore. Managed to record this lamp swaying. #gempa #seismology #sismo #terremoto #geology pic.twitter.com/b1CdcxrCLm — GeoGeorge (@GeoGeorgeology) November 18, 2022 Preliminary M6.9 #Earthquake – Learn more about us at https://t.co/ojzht2DDAL – EVENT: https://t.co/WbAhjnStUl pic.twitter.com/W5SOXtMdjn — Raspberry Shake Earthquake Channel (@raspishakEQ) November 18, 2022 I love this figure by Kyle Bradley – really highlights the Mentawai Seismic Gap, a region at high risk of a large tsunamigenic earthquake offshore Sumatra. https://t.co/DJ1MSuKGVa pic.twitter.com/j8A0LjReNO — Dr. Judith Hubbard (@JudithGeology) March 18, 2022 No #tsunami threat to Australia from magnitude 6.8 #earthquake near Southwest of Sumatra, Indonesia. Latest advice at https://t.co/Tynv3Zygqi. pic.twitter.com/ISugUTXpVm — Bureau of Meteorology, Australia (@BOM_au) November 18, 2022 NO TSUNAMI THREAT! An earthquake occurred in South Sumatra region with following preliminary parameters 👇🏼 There is no tsunami threat to SL at present & coastal areas of SL are declared safe.#Tsunami #NoThreat #SriLanka #LKA pic.twitter.com/CPQMp12dqD — Department of Meteorology Sri Lanka (@SLMetDept) November 18, 2022 Earthquakes commonly occur near Sumatra, as the Indo-Australian Plate subducts under the Sunda Plate. The M6.9 earthquake occurred at a depth of 25 km, likely on the subduction interface.https://t.co/OM7bvJsmTO pic.twitter.com/NS3rGVd8hR — EarthScope Consortium (@EarthScope_sci) November 18, 2022 Surface waves from a M6.9 earthquake near Bengkulu, Indonesia at 18/11/2022 13:37:09UTC, received in the UK approximately an hour after the earthquake on @BGS and @raspishake devices. The frequency of these waves is shown on a plot from the BGS Elmsett seismometer. @rdlarter pic.twitter.com/OQkXOm5K1o — Mark Vanstone (@wmvanstone) November 19, 2022 Waves from the M6.9 earthquake southwest of Sumatra shown on a nearby station using Station Monitor. https://t.co/Tir0KZmCJF pic.twitter.com/H5AjBzaKRH — EarthScope Consortium (@EarthScope_sci) November 18, 2022 Location and First-motion mechanism: Mwp6.8 #earthquake Southwest of Sumatra, Indonesia https://t.co/kCIw9Vypa6 https://t.co/xebYrDiQ5S pic.twitter.com/May21uExD6 — Anthony Lomax 😷🇪🇺🌍🇺🇦 (@ALomaxNet) November 18, 2022 Watch the waves from the M6.9 earthquake in Sumatra, Indonesia roll across seismic stations in North America. (THREAD 🧵) pic.twitter.com/JMolvkAy4b — EarthScope Consortium (@EarthScope_sci) November 18, 2022 Global surface and body wave sections from the M6.9 earthquake southwest of Sumatra, Indonesiahttps://t.co/a0ciLbpC9x pic.twitter.com/T4HDlrwvjy — EarthScope Consortium (@EarthScope_sci) November 18, 2022 Back projection for the M6.9 earthquake southwest of Sumatra, Indonesiahttps://t.co/SLKRaU3oUA pic.twitter.com/glLYRXLj7X — EarthScope Consortium (@EarthScope_sci) November 18, 2022 Earthquakes commonly occur near Sumatra, as the Indo-Australian Plate subducts under the Sunda Plate. The M6.9 earthquake occurred at a depth of 25 km, likely on the subduction interface.https://t.co/OM7bvJsmTO pic.twitter.com/NS3rGVd8hR — EarthScope Consortium (@EarthScope_sci) November 18, 2022 Mw=6.9, SOUTHWEST OF SUMATRA, INDONESIA (Depth: 19 km), 2022/11/18 13:37:06 UTC – Full details here: https://t.co/uLuj3Ztf0a pic.twitter.com/3V9bk1wFaq — Earthquakes (@geoscope_ipgp) November 18, 2022 Preliminary M6.9 #Earthquake – Learn more about us at https://t.co/ojzht2DDAL – EVENT: https://t.co/WbAhjnStUl pic.twitter.com/W5SOXtMdjn — Raspberry Shake Earthquake Channel (@raspishakEQ) November 18, 2022
Early this morning I received some notifications of earthquakes along the Tonga trench (southwestern central Pacific Ocean). It was about 2am my local time. I work on the tsunami program for the California state tsunami program (CTP) and we respond to tsunami to (1) help local communities do their first response activities so that they can help reduce suffering and to (2) document the impact of these tsunami. Because of this work, our team is “at the ready” 24 hours a day, 7 days a week, to respond to these events. Luckily, this event was unlikely to generate a tsunami that would impact California. I went back to sleep. This morning I put together a report and checked to see if there was a tsunami generated. Here is one place that I check for tsunami records as observed on tide gages http://www.ioc-sealevelmonitoring.org/map.php. I did not see anything convincing. This earthquake, from last night my time, has a magnitude of M 7.3. https://earthquake.usgs.gov/earthquakes/eventpage/us7000ip0l/executive This area of the Earth has a plate boundary fault system called a subduction zone. A subduction zone is a convergent plate boundary, which means that the plates on either side of the boundary move towards each other. Here, the Pacific plate dives westwards beneath the Australia plate, forming the Tonga trench. Below is a schematic illustration showing what these plates may look like if we cut into the Earth and viewed this subduction zone from the side. Note the Pacific plate on the right and the Australia plate on the left, with the megathrust subduction zone fault where they meet. This illustration shows where earthquakes may happen along this plate boundary. There could be interface earthquakes along the megathrust fault (megathrust earthquakes). These are what most people are familiar with when they are thinking about tsunami (e.g., the 2011 Great East Japan Earthquake and Tsunami). In the upper plate (the Australia plate), there can be crustal fault earthquakes. In the lower plate (the Pacific plate) there can be slab earthquakes (events within the crust, aka the slab), and there can be outer rise earthquakes). The outer rise is a part of the plate that is warping up and down because of the forces adjacent to the subduction zone. This warping can cause extension in the upper part, and compression in the lower part, of this plate. This 11 Nov 2022 M 7.3 earthquake was a compressional (reverse) earthquake in the outer rise region of this plate boundary. It was pretty deep (for oceanic crust) so fits nicely in the correct place in this illustration: But megathrust earthquakes are not the only type of earthquake that can cause a tsunami. The 2009 magnitude M 8.1 extensional (normal) fault earthquake near Samoa and American Samoa caused a tsunami that inundated the nearby islands (causing lots of damage and human suffering). This tsunami also travelled across the Pacific Ocean to impact California! (This is why the California Tsunami Program monitors tsunami across the Pacific Basin, so that we can help reduce suffering through the evacuation of coastal areas. Remember, the entire coast of California is a Tsunami Hazard Area.)
Bathymetric map of the Tonga–Kermadec arc system. Map showing the depth of the subducted slab beneath the Tonga–Kermadec arc system. Louisville seamount ages are after Koppers et al.49 ELSC, eastern Lau-spreading centre; DSDP, Deep Sea Drilling Programme; NHT, Northern Havre Trough; OT, Osbourn Trough; VFR, Valu Fa Ridge. Arrows mark total convergence rates.
Earthquakes and subducted slabs beneath the Tonga–Fiji area. The subducting slab and detached slab are defined by the historic earthquakes in this region: the steeply dipping surface descending from the Tonga Trench marks the currently active subduction zone, and the surface lying mostly between 500 and 680 km, but rising to 300 km in the east, is a relict from an old subduction zone that descended from the fossil Vitiaz Trench. The locations of the mainshocks of the two Tongan earthquake sequences discussed by Tibi et al. are marked in yellow (2002 sequence) and orange (1986 series). Triggering mainshocks are denoted by stars; triggered mainshocks by circles. The 2002 sequence lies wholly in the currently subducting slab (and slightly extends the earthquake distribution in it),whereas the 1986 mainshock is in that slab but the triggered series is located in the detached slab,which apparently contains significant amounts of metastable olivine
bathymetry, and major tectonic element map of the study area. The Tonga and Vanuatu subduction systems are shown together with the locations of earthquake epicenters discussed herein. Earthquakes between 0 and 70 km depth have been removed for clarity. Remaining earthquakes are color-coded according to depth. Earthquakes located at 500–650 km depth beneath the North Fiji Basin are also shown. Plate motions for Vanuatu are from the U.S. Geological Survey, and for Tonga from Beavan et al. (2002) (see text for details). Dashed line indicates location of cross section shown in Figure 3. NFB—North Fiji Basin; HFZ—Hunter Fracture Zone.
Map showing distribution of slab segments beneath the Tonga-Vanuatu region. West-dipping Pacifi c slab is shown in gray; northeast-dipping Australian slab is shown in red. Three detached segments of Australian slab lie below the North Fiji Basin (NFB). HFZ—Hunter Fracture Zone. Contour interval is 100 km. Detached segments of Australian plate form sub-horizontal sheets located at ~600 km depth. White dashed line shows outline of the subducted slab fragments when reconstructed from 660 km depth to the surface. When all subducted components are brought to the surface, the geometry closely approximates that of the North Fiji Basin.
Previous interpretation of combined P-wave tomography and seismicity from van der Hilst (1995). Earthquake hypocenters are shown in blue. The previous interpretation of slab structure is contained within the black dashed lines. Solid red lines mark the surface of the Pacifi c slab (1), the still attached subducting Australian slab (2a), and the detached segment of the Australian plate (2b). UM—upper mantle;
Simplified plate tectonic reconstruction showing the progressive geometric evolution of the Vanuatu and Tonga subduction systems in plan view and in cross section. Initiation of the Vanuatu subduction system begins by 10 Ma. Initial detachment of the basal part of the Australian slab begins at ca. 5–4 Ma and then sinking and collision between the detached segment and the Pacifi c slab occur by 3–4 Ma. Initial opening of the Lau backarc also occurred at this time. Between 3 Ma and the present, both slabs have been sinking progressively to their current position. VT—Vitiaz trench; dER—d’Entrecasteaux Ridge.
Map of the Southwest Pacific Ocean showing the regional tectonic setting and location of the two dredged profiles. Depth contours in kilometres. The presently active arcs comprise New Zealand–Kermadec Ridge–Tonga Ridge, linked with Vanuatu by transforms associated with the North Fiji Basin. Colville Ridge–Lau Ridge is the remnant arc. Havre Trough–Lau Basin is the active backarc basin. Kermadec–Tonga Trench marks the site of subduction of Pacific lithosphere westward beneath Australian plate lithosphere. North and South Fiji Basins are marginal basins of late Neogene and probable Oligocene age, respectively. 5.4sK–Ar date of dredged basalt sample (Adams et al., 1994).
Large subduction-zone interplate earthquakes (large open gray stars) labeled with event date, Mw, GCMT focal mechanisms, and GPS velocity vectors (gray arrows and black triangles labeled with station name). GPS velocities are listed in Table 3. Black lines indicate the Tonga–Kermadec and Vanuatu trenches. Note that the 2009/09/29 Samoa–Tonga outer trench-slope event (Mw 8.1) triggered large interplate doublets (both of Mw 7.8; Lay et al., 2010). The Pacific plate subducts westward beneath the Australian plate along the Tonga–Kermadec trench, whereas the Australian plate subducts eastward beneath the Vanuatu arc and North Fiji basin. The opposite orientation between the Tonga–Kermadec and Vanuatu subduction systems is due to complex and broad back-arc extension in the Lau and North Fiji basins (Pelletier et al., 1998).
Regional map of moderate-sized (mb > 4:7) shallow-focus repeating earthquakes and background seismicity along the (a) Tonga–Kermadec and (b) Vanuatu (former New Hebrides) subduction zones. Shallow repeating earthquakes (black stars) and their available Global Centroid Moment Tensor (GCMT; Dziewoński et al., 1981; Ekström et al., 2003) are labeled with event date and doublet/cluster id where applicable. Colors of GCMT are used to distinguish nearby different repeaters. Source parameters for the clusters and doublets are listed in Tables 1 and 2. Background seismicity is shown as gray dots and large interplate earthquakes (moment magnitude, Mw > 7:3) since 1976 are shown as large open gray stars. Black lines indicate the trench (Bird, 2003) and slab contour at 50-km depth (Gudmundsson and Sambridge, 1998). Repeating earthquake clusters in the (a) T1 and T2 plate-interface regions in Tonga and (b) V3 plate-interface region in Vanuatu are used to study the fault-slip rate ( _d). A regional map of the Tonga–Kermadec–Vanuatu subduction zones is #EarthquakeReport for M 7.3 #Earthquake along outer rise near the Tonga trench reverse (compressional) mechanism south of analogues incl tsunamigenic 2009 M 8.1 (tho that was extensional)https://t.co/gQEdISt9eD learn more abt regional tectonics herehttps://t.co/eDsUON2Mly pic.twitter.com/DvMnY4rWck — Jason "Jay" R. Patton (@patton_cascadia) November 11, 2022 #EarthquakeReport for M 7.3 #Earthquake near the Tonga trench thrust (compressional) earthquake along the outer rise no #Tsunami observed on tide gages report here includes my interpretation and a regional tectonic summary:https://t.co/ze2s3bb7Vn pic.twitter.com/2M3SZaYE19 — Jason "Jay" R. Patton (@patton_cascadia) November 11, 2022 The region near todays M7.3 earthquake is incrediblely active due to the high rates of convergence between the Australian and Pacific Plates. Since 1900, 40 M7.5+ earthquakes have been recorded, as well as at least 3 M8+ events. https://t.co/avVOX0LcGH pic.twitter.com/dN9mIrwgwN — Wendy Bohon, PhD 🌏 (@DrWendyRocks) November 11, 2022 Fri Nov 11 10:48:00 2022 UTC * HAZARDOUS TSUNAMI WAVES FROM THIS EARTHQUAKE ARE POSSIBLE WITHIN 300 KM OF THE EPICENTER ALONG THE COASTS OF — よっしみ~☆🌏 (@yoshimy_s) November 11, 2022 Seismic waves from the Tonga 7.3 #earthquake, as arriving at a @raspishakEQ station of the @GEO3BCN_CSIC educational network in NE Iberia pic.twitter.com/K6YZPQf1JU — Jordi Diaz Cusi (@JDiazCusi) November 11, 2022 Recent Earthquake Teachable Moment for the M7.3 Tonga earthquake https://t.co/PJBT5jgOTy pic.twitter.com/h0kTCejygS — IRIS Earthquake Sci (@IRIS_EPO) November 11, 2022 Global surface and body wave sections from the M7.3 earthquake near Tongahttps://t.co/mz6A6vgD9F pic.twitter.com/0psyiRcDum — IRIS Earthquake Sci (@IRIS_EPO) November 11, 2022 Mw=7.3, TONGA ISLANDS REGION (Depth: 43 km), 2022/11/11 10:48:42 UTC – Full details here: https://t.co/vqxit49tby pic.twitter.com/m16qoCB5wK — Earthquakes (@geoscope_ipgp) November 11, 2022 Watch the waves from the M7.3 earthquake near Tonga roll across seismic stations in North America (THREAD 🧵) pic.twitter.com/hupVx0WfpQ — IRIS Earthquake Sci (@IRIS_EPO) November 11, 2022 Section from today's M7.3 earthquake in the Tonga region at 2022-11-11 10:48:45UTC recorded on the worldwide @raspishake network. See: https://t.co/LS1S4JlAqX. Uses @obspy and @matplotlib. pic.twitter.com/Jdz1FlEZN2 — Mark Vanstone (@wmvanstone) November 11, 2022 A cross-section of seismicity, with the focal mechanisms projected into the vertical plane, shows the three deep quakes with purple outlines. These events were close to the deepest quakes in this area, where the subducted slab possibly is deflected by the 670 km discontinuity. pic.twitter.com/V09EYGWJRd — Jascha Polet (@CPPGeophysics) November 11, 2022
I don’t always have the time to write a proper Earthquake Report. However, I prepare interpretive posters for these events. 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. There was a magnitude M 7.6 earthquake in Mexico on 19 September 2022. https://earthquake.usgs.gov/earthquakes/eventpage/us7000i9bw/executive I am catching up on some Earthquake Reports that I did not yet post since my website was being migrated to a more secure and reliable server (and more expensive). The tectonics of coastal southwestern Mexico is dominated by the convergent plate boundary between the Cocos plate (to the southwest) and the North America plate (to the northeast). Here, the Cocos plate subducts below (goes underneath) the North America plate. The fault between these plates is called a megathrust subduction zone fault and the plate boundary forms the Middle America trench. This M 7.6 earthquake mechanism (the “moment tensor”) shows that this event was a compressional earthquake (reverse or thrust). Based on it’s location, the event probably happened along the megathrust fault. This earthquake even generated a tsunami recorded on tide gages in the region!
Development of the Tepic–Zacoalco (TZ), Colima, and Chapala rifts. The TZ rift is formed by the Rivera slab rollback, enhanced by the toroidal flow around the slab edges. The Colima rift is probably related with the oblique convergence between Rivera and NAM plates at ~5 Ma.
Tectonic setting of the Caribbean Plate. Grey rectangle shows study area of Fig. 2. Faults are mostly from Feuillet et al. (2002). PMF, Polochic–Motagua faults; EF, Enriquillo Fault; TD, Trinidad Fault; GB, Guatemala Basin. Topography and bathymetry are from Shuttle Radar Topography Mission (Farr&Kobrick 2000) and Smith & Sandwell (1997), respectively. Plate velocities relative to Caribbean Plate are from Nuvel1 (DeMets et al. 1990) for Cocos Plate, DeMets et al. (2000) for North America Plate and Weber et al. (2001) for South America Plate.
A. Geodynamic and tectonic setting alongMiddle America Subduction Zone. JB: Jalisco Block; Ch. Rift—Chapala rift; Co. rift—Colima rift; EGG—El Gordo Graben; EPR: East Pacific Rise; MCVA: Modern Chiapanecan Volcanic Arc; PMFS: Polochic–Motagua Fault System; CR—Cocos Ridge. Themain Quaternary volcanic centers of the TransMexican Volcanic Belt (TMVB) and the Central American Volcanic Arc (CAVA) are shown as blue and red dots, respectively. B. 3-D view of the Pacific, Rivera and Cocos plates’ bathymetrywith geometry of the subducted slab and contours of the depth to theWadati–Benioff zone (every 20 km). Grey arrows are vectors of the present plate convergence along theMAT. The red layer beneath the subducting plate represents the sub-slab asthenosphere.
Marine magnetic anomalies and fracture zones that constrain tectonic reconstructions such as those shown in Figure 4 (ages of anomalies are keyed to colors as explained in the legend; all anomalies shown are from University of Texas Institute for Geophysics PLATES [2000] database): (1) Boxed area in solid blue line is area of anomaly and fracture zone picks by Leroy et al. (2000) and Rosencrantz (1994); (2) boxed area in dashed purple line shows anomalies and fracture zones of Barckhausen et al. (2001) for the Cocos plate; (3) boxed area in dashed green line shows anomalies and fracture zones from Wilson and Hey (1995); and (4) boxed area in red shows anomalies and fracture zones from Wilson (1996). Onland outcrops in green are either the obducted Cretaceous Caribbean large igneous province, including the Siuna belt, or obducted ophiolites unrelated to the large igneous province (Motagua ophiolites). The magnetic anomalies and fracture zones record the Cenozoic relative motions of all divergent plate pairs infl uencing the Central American subduction zone (Caribbean, Nazca, Cocos, North America, and South America). When incorporated into a plate model, these anomalies and fracture zones provide important constraints on the age and thickness of subducted crust, incidence angle of subduction, and rate of subduction for the Central American region. MCSC—Mid-Cayman Spreading Center.
Rupture zones (ellipses) and epicenters (triangles and circles) of large shallow earthquakes (after KELLEHER et al., 1973) and bathymetry (CHASE et al., 1970) along the Middle America arc. Note that six gaps which have earthquake histories have not ruptured for 40 years or more. In contrast, the gap near the intersection of the Tehuantepec ridge has no known history of large shocks. Contours are in fathoms.
The study area encompasses Guerrero and Oaxaca states of Mexico. Shaded ellipse-like areas annotated with the years are rupture areas of the most recent major thrust earthquakes (M≥6.5) in the Mexican subduction zone. Triangles show locations of permanent GPS stations. Small hexagons indicate campaign GPS sites. Arrows are the Cocos-North America convergence vectors from NUVEL-1A model (DeMets et al., 1994). Double head arrow shows the extent of the Guerrero seismic gap. Solid and dashed curves annotated with negative numbers show the depth in km down to the surface of subducting Cocos plate (modified from Pardo and Su´arez, 1995, using the plate interface configuration model for the Central Oaxaca from this study, the model for Guerrero from Kostoglodov et al. (1996), and the last seismological estimates in Chiapas by Bravo et al. (2004). MAT, Middle America trench.
FOS = Resisting Force / Driving Force #EarthquakeReport for the M 7.6 (likely) subduction zone #Earthquake in #Mexico on 19 Sept 2022 catching up on reports that happened after my website went down generated 0.6-1.7m wave height #Tsunami — Jason "Jay" R. Patton (@patton_cascadia) November 9, 2022
I don’t always have the time to write a proper Earthquake Report. However, I prepare interpretive posters for these events. 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. https://earthquake.usgs.gov/earthquakes/eventpage/us7000ilwt/executive This is possibly one of the most mysterious earthquakes of the year. I forgot to write this up at the time so need to fill in more details after I am done working up my annual summary.
Earthquake Report M 7.0 Solomon Isles
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
Some Relevant Discussion and Figures
(LP); Manus Basin (MB); New Britain trench (NBT); North Bismarck microplate (NBP); North Solomon trench (NST); Ontong Java Plateau (OJP); Ramu-Markham fault (RMF); San Cristobal trench (SCT); Solomon Sea plate (SSP); South Bismarck microplate (SBP); Trobriand trough (TT); projected Vanuatu slab (VS); West Bismarck fault (WBF); West Torres Plateau (WTP); Woodlark Basin (WB).
New Britain | Solomon | Bougainville | New Hebrides | Tonga | Kermadec Earthquake Reports
General Overview
Earthquake Reports
Social Media
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report: M 6.9 Sumatra
I need to run to catch the sunset and will complete the intro later tonight.
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
Some Relevant Discussion and Figures
Seismic Hazard and Seismic Risk
Tsunami Hazard
Indonesia | Sumatra
General Overview
Earthquake Reports
Social Media
ID: #rs2022wsherl
Southwest of Sumatra, Indonesia
2022-11-18 13:37 UTC@raspishake #QuakeView
ID: #rs2022wsherl
Southwest of Sumatra, Indonesia
2022-11-18 13:37 UTC@raspishake #QuakeView
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report: M 7.3 Tonga trench outer rise
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
Some Relevant Discussion and Figures
TZ—transition zone; LM—lower mantle.
shown in the inset figure, with the gray dotted box indicating the expanded region in the main figure.
New Britain | Solomon | Bougainville | New Hebrides | Tonga | Kermadec Earthquake Reports
General Overview
Earthquake Reports
Social Media
Mag: 7.5 Depth: 33
Coords: 19.322 S 172.01 W
Location: TONGA ISLANDS REGION
NIUE AND TONGA pic.twitter.com/lm1RMEJ0o8
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report: M 7.6 Earthquake in Mexico
Below is my interpretive poster for this earthquake
I include some inset figures.
Supportive Figures
Earthquake Triggered Landslides
Social Media:
probably triggered landslides/induced liquefactionhttps://t.co/9zpN2ZlAhw pic.twitter.com/tMDb4mSwCw
Mexico | Central America
General Overview
Earthquake Reports
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report: M 6.0 northeast Pacific Ocean
Below is my interpretive poster for this earthquake
I include some inset figures.
Pacific Ocean | Hawai’i’ Earthquake Reports
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.