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
I need to run to catch the sunset and will complete the intro later tonight.
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.
- Here are the tide gage data. I label the locations for these two gage sites on the interpretive poster.
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.
- https://earthquake.usgs.gov/earthquakes/eventpage/official20070912111026830_34/executive
- https://earthquake.usgs.gov/earthquakes/eventpage/usp000fn2b/executive
- https://earthquake.usgs.gov/earthquakes/eventpage/usp0009txv/executive
- https://earthquake.usgs.gov/earthquakes/eventpage/usp000hnj4/executive
- https://earthquake.usgs.gov/earthquakes/eventpage/usp000a9kc/executive
- https://earthquake.usgs.gov/earthquakes/eventpage/usp000d0v4/executive
- https://earthquake.usgs.gov/earthquakes/eventpage/usp000fzx4/executive
- https://earthquake.usgs.gov/earthquakes/eventpage/usp000fn3d/executive
Here are some of the larger historic earthquakes in this area, ordered by magnitude:
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 ≥ 6.5 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 showing historic seismicity, fault lines, and the global strain rate map (red shows area of higher tectonic strain).
- To the left of the strain map is a figure that shows historic earthquake rupture areas and a representation of how strongly the megathrust subduction fault is (Chlieh et al., 2008).
- In the upper left corner are maps that show the seismic hazard and seismic risk for Indonesia. I spend more time explaining this below.
- In the center top-left is a map that shows earthquake intensity using the Modified Mercalli Intensity (MMI) Scale.
- In the lower left center is a low angle oblique view of a cut away of the Earth along the subduction zone in Sumatra, Indonesia from EOS.
- Above the oblique view is a plot of the tide gage from Cocos, Island.
- In the right center is a great figure from Philobosian et al. (2014) that shows the slip patches from the subduction zone earthquakes in this region.
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
- Here is my map. I include the references below in blockquote.
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).
- This is the main figure from Hayes et al. (2013) from the Seismicity of the Earth series. There is a map with the slab contours and seismicity both colored vs. depth. There are also some cross sections of seismicity plotted, with locations shown on the map.
- Here is a great figure from Philobosian et al. (2014) that shows the slip patches from the subduction zone earthquakes in this region.
- This is a figure from Philobosian et al. (2012) that shows a larger scale view for the slip patches in this region. Note that today’s earthquake happened at the edge of the 7.9 earthquake slip patch.
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).
- Here are a series of figures from Chlieh et al. (2008 ) that show their data sources and their modeling results. I include their figure captions below in blockquote.
- This figure shows the coupling model (on the left) and the source data for their inversions (on the right). Their source data are vertical deformation rates as measured along coral microattols. These are from data prior to the 2004 SASZ earthquake.
- This is a similar figure, but based upon observations between June 2005 and October 2006.
- This is a similar figure, but based on all the data.
- Here is the figure I included in the poster above.
- Here is the Chlieh et al. (2008) figure with the 18 November 2022 M 6.9 earthquake plotted as a blue star.
- Note how the M 6.9 happened in a region of low seismogenic coupling. Beware that this is also in an area without any geodetic (GPS/GNSS) nor paleogeodetic (coral microattol) observations (the sources of data for the coupling model).
- This figure shows the authors’ estimate for the moment deficit in this region of the subduction zone. This is an estimate of how much the plate convergence rate, that is estimated to accumulate as tectonic strain, will need to be released during subduction zone earthquakes.
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].
- For a review of the 2004 and 2005 Sumatra Andaman subduction zone (SASZ) earthquakes, please check out my Earthquake Report here. Below is the poster from that report. On that report page, I also include some information about the 2012 M 8.6 and M 8.2 Wharton Basin earthquakes.
- I include some inset figures in the poster.
- In the upper left corner, I include a map that shows the extent of historic earthquakes along the SASZ offshore of Sumatra. This map is a culmination of a variety of papers (summarized and presented in Patton et al., 2015).
- In the upper right corner I include a figure that is presented by Chlieh et al. (2007). These figures show model results from several models. Each model is represented by a map showing the amount that the fault slipped in particular regions. I present this figure below.
- In the lower right corner I present a figure from Prawirodirdjo et al. (2010). This figure shows the coseismic vertical and horizontal motions from the 2004 and 2005 earthquakes as measured at GPS sites.
- In the lower left corner are the MMI intensity maps for the two SASZ earthquakes. Note these are at different map scales. I also include the MMI attenuation curves for these earthquakes below the maps. These plots show the reported MMI intensity data as they relate to two plots of modeled estimates (the orange and green lines). These green dots are from the USGS “Did You Feel It?” reports compared to the estimates of ground shaking from Ground Motion Prediction Equation (GMPE) estimates. GMPE are empirical relations between earthquakes and recorded seismologic observations from those earthquakes, largely controlled by distance to the fault, ray path (direction and material properties), and site effects (the local geology). When seismic waves propagate through sediment, the magnitude of the ground motions increases in comparison to when seismic waves propagate through bedrock. The orange line is a regression of data for the central and eastern US and the green line is a regression through data from the western US.
- Here is a map from Jacob et a. (2014) that shows the structure of the eastern Indian Ocean. Figure text below.
- Here is the map from Jacobs et a. (2014). Figure text below.
- This is a fascinating figure from Jacob et al. (2014). This shows a reconstruction of the magntic anomalies for the oceanic crust as they are subducted beneath Eurasia.
- Finally, these authors present what their reconstruction implicates about this plate boundary system.
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.
Seismic Hazard and Seismic Risk
- These are the two maps shown in the map above, 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 Indonesia.
- 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 Indonesia.
Tsunami Hazard
- Here are two maps that show the results of probabilistic tsunami modeling for the nation of Indonesia (Horspool et al., 2014). These results are similar to results from seismic hazards analysis and maps. The color represents the chance that a given area will experience a certain size tsunami (or larger).
- The first map shows the annual chance of a tsunami with a height of at least 0.5 m (1.5 feet). The second map shows the chance that there will be a tsunami at least 3 meters (10 feet) high at the coast.
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).
- M 9.2 Andaman-Sumatra subduction zone 2014 Earthquake Anniversary
- M 9.2 Andaman-Sumatra subduction zone SASZ Fault Deformation
- M 9.2 Andaman-Sumatra subduction zone 2016 Earthquake Anniversary
- 2022.11.18 M 6.9 Sumatra
- 2022.02.25 M 6.2 Sumatra
- 2020.05.06 M 6.8 Banda Sea
- 2019.08.02 M 6.9 Indonesia
- 2019.06.23 M 7.3 Banda Sea
- 2019.04.12 M 6.8 Sulawesi, Indonesia
- 2018.09.28 M 7.5 Sulawesi
- 2018.10.16 M 7.5 Sulawesi UPDATE #1
- 2018.08.19 M 6.9 Lombok, Indonesia
- 2018.08.05 M 6.9 Lombok, Indonesia
- 2018.07.28 M 6.4 Lombok, Indonesia
- 2017.12.15 M 6.5 Java
- 2017.08.31 M 6.3 Mentawai, Sumatra
- 2017.08.13 M 6.4 Bengkulu, Sumatra, Indonesia
- 2017.05.29 M 6.8 Sulawesi, Indonesia
- 2017.03.14 M 6.0 Sumatra
- 2017.03.01 M 5.5 Banda Sea
- 2016.10.19 M 6.6 Java
- 2016.03.02 M 7.8 Sumatra/Indian Ocean
- 2015.07.22 M 5.8 Andaman Sea
- 2015.11.08 M 6.4 Nicobar Isles
- 2012.04.11 M 8.6 Sumatra outer rise
- 2004.12.26 M 9.2 Andaman-Sumatra subduction zone
Indonesia | Sumatra
General Overview
Earthquake Reports
Social Media
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
ID: #rs2022wsherl
Southwest of Sumatra, Indonesia
2022-11-18 13:37 UTC@raspishake #QuakeView– 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
ID: #rs2022wsherl
Southwest of Sumatra, Indonesia
2022-11-18 13:37 UTC@raspishake #QuakeView– 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
- Frisch, W., Meschede, M., Blakey, R., 2011. Plate Tectonics, Springer-Verlag, London, 213 pp.
- Hayes, G., 2018, Slab2 – A Comprehensive Subduction Zone Geometry Model: U.S. Geological Survey data release, https://doi.org/10.5066/F7PV6JNV.
- Holt, W. E., C. Kreemer, A. J. Haines, L. Estey, C. Meertens, G. Blewitt, and D. Lavallee (2005), Project helps constrain continental dynamics and seismic hazards, Eos Trans. AGU, 86(41), 383–387, , https://doi.org/10.1029/2005EO410002. /li>
- Jessee, M.A.N., Hamburger, M. W., Allstadt, K., Wald, D. J., Robeson, S. M., Tanyas, H., et al. (2018). A global empirical model for near-real-time assessment of seismically induced landslides. Journal of Geophysical Research: Earth Surface, 123, 1835–1859. https://doi.org/10.1029/2017JF004494
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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. There was a magnitude M 7.6 earthquake in Mexico on 1 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 will be filling this in over the next few days and wanted to start collating social media materials for this event. This week, CGS sent teams to various harbors & beaches on the California coast to collect measurements, photos, & videos documenting the effects of the Jan. 15 #tsunami from Tonga. This info helps us understand how future tsunami might impact our coastal harbors & communities. pic.twitter.com/xGa8zmNNNs — California Geological Survey (@CAGeoSurvey) January 21, 2022 #Tonga #Tsunami January 15 2022 — California Geological Survey (@CAGeoSurvey) February 2, 2022 After two weeks of work I can finally share my 3D reconstruction of the gigantic ash cloud from the January 15 Hunga #Tonga-Hunga-Ha'apai #eruption Parts likely reached *close to 60km* according to my reconstruction, that's beyond the stratosphere and inside the mesosphere!🧵 pic.twitter.com/qMzPSjZj7P — Simeon Schmauß (@stim3on) February 2, 2022 It is incredible to see how the #Andes bounced back part of the #Tonga atmospheric Lamb wave on its first cross over South America!. Here depicted with signal processed IR data from the GOES 16 geostationary satellite pic.twitter.com/OLM0MD0neO — diego aliaga (@diegoaliaga2) January 28, 2022 Excellent thread on how you can best help disaster relief efforts (and why) from someone who knows from professional experience. Donate $ (not 👠s) to reputable relief organizations. This is true for most disaster relief. https://t.co/zj6AIUuCZC — Tim Dawson (@timblor) January 16, 2022 Here's my radio interview on KCBS today.https://t.co/mwAnGWqy59 — Jason "Jay" R. Patton (@patton_cascadia) January 16, 2022 What lies beneath? Revealing the massive Hunga #caldera (5km diameter) below the water line, 3D model using elevation data @theAGU + bathymetrics @NOAA #Tonga #Blender pic.twitter.com/PmpVOfX8HD — frédérik ruys (@fruys) January 16, 2022 This is a truly excellent short article by @LoriDengler about yesterday’s #tsunami and eruption event. It makes it clear just how unique this was, and why the @NWS_NTWC folks had to improvise (brilliantly) to get the alert out. https://t.co/meypb1w2k9 — Harold Tobin (@Harold_Tobin) January 16, 2022 This is a small volcanic island but below the ocean the volcano is huge at around 1.8 km high and 20km wide. Much of the 2014-15 cone is now gone. Read more about what we know by @scronin70: https://t.co/nMNQYGcLDw pic.twitter.com/Ejn3z6e1I4 — Dr Janine Krippner (@janinekrippner) January 15, 2022 Scientists said the volcano had been puffing away for about a month before rising magma, superheated to around 1,000 degrees Celsius (1,832 Fahrenheit), met with 20 degree (68 Fahrenheit) seawater on Saturday, causing an instantaneous and massive explosion pic.twitter.com/iNVC2tB3XM — Reuters (@Reuters) January 19, 2022 An underwater volcano off Tonga erupted on Jan. 15, triggering tsunami warnings and evacuation orders in Japan and causing large waves in several South Pacific islands, where footage on social media showed waves crashing into coastal homes pic.twitter.com/L7uzK59jG7 — Reuters (@Reuters) January 19, 2022 Observations from Japan on why the far-field tsunami was likely triggered by air-sea coupling, not the standard shallow-water wave propagation from the source. https://t.co/70O5V095Xs — Harold Tobin (@Harold_Tobin) January 20, 2022 Why the ocean depth of the Hunga Tonga caldera created the 'sweet spot' that produced such an explosive eruption. Graphic based on research by @scronin70 https://t.co/D8ZBpAQkql pic.twitter.com/3gkDDZIqzm — Alistair Hamill (@lcgeography) January 21, 2022 Lessons from the Tonga Tsunami https://t.co/ZYPy87AzKW — CREW.org (@CascadiaEQ) January 25, 2022 New preprint out on ESSOAr – "Tonga eruption triggered waves propagating globally from surface to edge of space" – in which we look at the deeply unusual atmospheric waves generated by the recent Hunga Tonga eurption. pic.twitter.com/IJfMgb1Bt9 — Corwin Wright (@CorwinWright) March 3, 2022 *** California is in a NWS Tsunami "Advisory" – — California Geological Survey (@CAGeoSurvey) January 15, 2022 #Tsunami potential #AmericanSamoa #VolcanicEruption https://t.co/6bL0wRlNmX pic.twitter.com/QqLXC79pQK — Jason "Jay" R. Patton (@patton_cascadia) January 15, 2022 #TsunamiReport for #TsunamiAdvisory for the west coast of the USA & #Canada #Alaska #BritishColumbia #Washington #Oregon #California see https://t.co/rEduVE2EDc for more updates and recommendations pic.twitter.com/gLkB833R22 — Jason "Jay" R. Patton (@patton_cascadia) January 15, 2022 #TsunamiAdvisory remains in effect for the #WestCoast, with peak tsunami wave heights of 1 to 3 feet possible. Main impacts expect to be strong rip currents and coastal flooding of some immediate coastal low-lying areas. #CAwx — NWS Eureka (@NWSEureka) January 15, 2022 #Tsunami expect to reach #SanFrancisco around 8:10 am this morning, which will correspond with #HighTide for #SanFrancisco at 9:09 am. Expect low lying inundation and minor flooding possible, especially for areas like #MarinHeadlands. #Cawx pic.twitter.com/PoR3WYZ13D — NWS Bay Area (@NWSBayArea) January 15, 2022 #Tsunami expect to reach #SanFrancisco around 8:10 am this morning, which will correspond with #HighTide for #SanFrancisco at 9:09 am. Expect low lying inundation and minor flooding possible, especially for areas like #MarinHeadlands. #Cawx pic.twitter.com/PoR3WYZ13D — NWS Bay Area (@NWSBayArea) January 15, 2022 #TsunamiAdvisory remains in effect for the #WestCoast, with peak tsunami wave heights of 1 to 2 feet possible. Main impacts expect to be strong rip currents, coastal flooding, and inundation of low lying areas is possible. Move to higher ground. #CAwx — NWS Bay Area (@NWSBayArea) January 15, 2022 A Tsunami Advisory has been issued for Humboldt Co. due to volcanic activity in the S. Pacific. A tsunami capable of producing strong currents that may be hazardous to swimmers, boats and coastal structures is expected beginning 7:30-8 a.m. Widespread inundation is not expected. — Humboldt Co OES (@HumCoOES) January 15, 2022 Wow. Evacuation orders for Berkeley and Albany west of hwy. pic.twitter.com/dRvaSkCLwa — Cian Dawson 🏳️🌈 (@cbdawson) January 15, 2022 #SF remains in a Tsunami Advisory Strong, dangerous currents WILL be present. Stay out of water and away from coastal areas. pic.twitter.com/nMYm0wxvPA — SAN FRANCISCO FIRE DEPARTMENT MEDIA (@SFFDPIO) January 15, 2022 We continue to monitor the #Tsunami closely. Please listen to local advisories — stay safe and off beaches that are under a warning. https://t.co/M1QdOhBleG — Gavin Newsom (@GavinNewsom) January 15, 2022 Great resource for the #Tongaeruption tsunami arrival times, amplitudes, and r/t tide gauge observations.https://t.co/XOESHxHSuX pic.twitter.com/StO7eQo4Dh — Peter de Menocal (@PdeMenocal) January 15, 2022 I did an interview about an hour ago summarizing what's going on for Washington coastal areas. #tsunami https://t.co/V3qFtCFTkH — Harold Tobin (@Harold_Tobin) January 15, 2022 #TsunamiReport for the #TongaVolcano #TongaTsunami observations of #Tsunami in the #Caribbean #Atlantic #GulfOfMexico no action required use https://t.co/rEduVE2EDc to see notifications and recommendations pic.twitter.com/OrhBzGOASY — Jason "Jay" R. Patton (@patton_cascadia) January 15, 2022 #TsunamiReport for #TongaTsunami #Tsunami advisories have all been cancelled for the west coast of the US & Hawai'i from https://t.co/rEduVE2EDc the [#mostimportant] first level Blooms Taxonomy for learning = #Discovery this event will not disappoint in this regard #StayTuned https://t.co/z8LpWAAOI7 pic.twitter.com/4zSgmpH9rX — Jason "Jay" R. Patton (@patton_cascadia) January 16, 2022 Update from Tongans on FB… clean up begins, #tsunami alert remains, masks advised. Stay safe, stay alert 🙏 #Tonga #tsunamitonga #TongaVolcano pic.twitter.com/GGxIw0Kw0u — Josephine Latu-Sanft (@JoLatuSanft) January 16, 2022 There has been another eruption from the volcano in Tonga. — National Weather Service WSO Pago Pago (@NWSPagoPago) January 16, 2022 Tonga Volcanic Eruption and Tsunami: World Bank Disaster Assessment Report Estimates Damages at US$90M https://t.co/bx6Iq5VTyb via @WorldBank — Jason "Jay" R. Patton (@patton_cascadia) March 7, 2022 ➡️https://t.co/ZDdvztAIKj https://t.co/oNuTw3G5s9 pic.twitter.com/LsA3PfAoJq — California Geological Survey (@CAGeoSurvey) January 17, 2022 A #Tsunami Advisory means: a dangerous wave is on the way. Strong and unusual currents are expected along the coast, and in bays, marinas, and harbors. Move to high ground and away from the shore. More at https://t.co/npoUHxEZLS. pic.twitter.com/MCLDdN9qPp — NWS Tsunami Alerts (@NWS_NTWC) January 15, 2022 #Tsunami INFO CA Tsunami Preparedness Guide website: https://t.co/UB3BAS55Pz — Nick Graehl (@nickgraehl) January 15, 2022 yes, don't forget to check out the #Tsunami Hazard Areas (where people might want to evacuate from during a tsunami event) for #California are available at https://t.co/9LPXadKWEi these are produced by the #CaliforniaTsunamiProgram a collaboration between @Cal_OES & @CAGeoSurvey pic.twitter.com/IaC13oef9b — Jason "Jay" R. Patton (@patton_cascadia) January 15, 2022 There are a number of #Tsunami HAZARDS that could directly impact harbors and boaters: continued… pic.twitter.com/1BRSOnjmYC — Nick Graehl (@nickgraehl) January 15, 2022 If you want to interact with all the tide gage data, here’s the NOAA interactive website that is pretty great!https://t.co/2SsAokmaB3 https://t.co/PMMLH35BJv pic.twitter.com/6nrXmekebL — Ryan Hollister (@phaneritic) January 15, 2022 Tsunami arrival + high tide = maximum wave run-ups pic.twitter.com/6mjQltYO45 — Brian Olson (@mrbrianolson) January 15, 2022 The #tsunami warning centers post all their messages to https://t.co/Em3fOFG82S. If you live on the US West Coast, Alaska, or British Columbia, make sure you check the messages for your region. pic.twitter.com/AJtJN9oZWg — Dr. Amy Williamson-Liuzzo (@AWilliamsonSci) January 15, 2022 If you're having a hard time interpreting news about this tsunami advisory — what the danger is and where — @DaveSnider breaks it down really well in this video on the warning center's facebook page.https://t.co/tHsstcS5xl — Ian Dickson (@IanJDickson) January 15, 2022 First signs of damage in the upper harbor. #santacruz. pic.twitter.com/p26hdpnSOn — Tim Cattera Photo (@TimCatteraPhoto) January 15, 2022 The Hunga Tonga-Hunga Ha'apai volcanic eruption was heard here in Alaska starting around 3:30 a.m. – 6,000 miles from the volcano! Infrasound measurements from the @alaska_avo confirm that it was indeed coincident with the volcanic pressure wave. Special thanks to Dr. David Fee. pic.twitter.com/Wp4tnwiaud — NWS Alaska Region (@NWSAlaska) January 15, 2022 2. Tsunamis are not one wave. It's more like sloshing and that sloshing can continue for a day. Just because the first wave has passed, it is not time to go see the beach. — Dr. Lucy Jones (@DrLucyJones) January 15, 2022 Don't be these people. Today is not the day for it. Stay off the coastal beaches and jetties. #wawx pic.twitter.com/4o0fhpJei8 — NWS Seattle (@NWSSeattle) January 15, 2022 Wondering why you didn't get an alert about the #Tonga tsunami and the #TsunamiAdvisory in WA this morning? There are many ways to get tsunami alerts and it's best to be signed up for many kinds! Learn more about tsunami alerts (and other hazard alerts) at https://t.co/iU0UZFRnC2 pic.twitter.com/aRkJ2CKB32 — Washington ShakeOut (@waShakeOut) January 15, 2022 After checking with @LoriDengler, I think that today is the first-ever Pacific-wide #tsunami alert from a volcanic eruption. Interestingly, the warning center needed an earthquake magnitude to issue the bulletin. So they made one up: mag 0.1! (Now changed to mag 1) pic.twitter.com/znjfUa1o3S — Harold Tobin (@Harold_Tobin) January 15, 2022 This was not your run of the mill way a #tsunami is generated. Most often its from plates shifting abruptly on the sea floor. This tsunami was essentially caused by a massive underwater explosion of molten rock and lava that displaced the water above it. pic.twitter.com/JyLwZYHcRp — NWS Los Angeles (@NWSLosAngeles) January 15, 2022 Not sure I have ever seen this before. My @noaaocean colleague just flagged this. The pressure wave caused by the #TongaVolcano is also actually causing a tsunami – in this case a meteotsunami of about 10cm in Puerto Rico. Wild. pic.twitter.com/EapEuNhjB5 — Greg Dusek (@DrGregDusek) January 15, 2022 A #volcano just erupted near #Tonga – but why was it there in the first place? Tonga sits on top of the #TongaKermadec #subductionzone, where the #PacificPlate sinks below the #AustralianPlate. The subducting #PacificPlate carries the culprit into the mantle: #water. 🧵1/3 https://t.co/Z1ORgcBK5l pic.twitter.com/XN5cUCT8Yg — Dr. Judith Hubbard (@JudithGeology) January 15, 2022 Fascinating part of the tsunami warning process today: This wasn't an earthquake, so the tsunami warnings were sent out with a default magnitude of 1. Shows that our whole system is set up for earthquake tsunamis. 1/2 pic.twitter.com/pwsBuicyyX — Jackie Caplan-Auerbach (@geophysichick) January 16, 2022 Be #prepared for tsunamis. — John Cassidy (@earthquakeguy) January 16, 2022 If you’re not already following all these great folks, then do yourself a favour and follow them. I’d also add to the list:@heatherkhandley @SquigglyVolcano @Volcanologist @VolcanoDoc@scarlett_jazmin@simoncarn https://t.co/RrfVVNGmQf — Mark Tingay (@CriticalStress_) January 17, 2022 Interactive Tsunami Flood Risk Map Asks: Are You in the Zone? https://t.co/WnvKidKNjE — Jason "Jay" R. Patton (@patton_cascadia) January 17, 2022 Great questions here about hydrophones as a tool to monitor submarine volcanism. This is my favorite topic, so @syabilazriAS is going to get a longer answer than maybe was desired. 😆🧵 https://t.co/VcbgmUEnZn — Jackie Caplan-Auerbach (@geophysichick) January 18, 2022 The highest concentration of sulfur dioxide (SO2) in the world right now is over the Pacific 📈 This is associated with the eruption of the Hunga-Tonga-Hunga-Ha'apai volcano 🌋 🧵 on what this means… pic.twitter.com/yjgT0yWdL8 — NIWA Weather (@NiwaWeather) January 17, 2022 For additional information on #TsunamiPrep check out "The TsunamiZone" @thetsunamizone and https://t.co/o336WXPPqj pic.twitter.com/dE1QT3QSPc — California Geological Survey (@CAGeoSurvey) January 17, 2022 High tide is around 9:30 AM along the Northwest California coast. Even though the initial wave is expected 7:30 AM to 8 AM, additional waves and strong currents will continue. As much as 3 feet of tsunami wave is expected. Stay back from the beaches and lowest-lying areas. #CAwx pic.twitter.com/BmoCVtJc2f — NWS Eureka (@NWSEureka) January 15, 2022 WATCH: Tsunami from Tonga volcano eruption starting to cause minor flooding in Santa Cruz, California pic.twitter.com/ELq8IKMEUV — BNO News (@BNONews) January 15, 2022 tsunami waves & high tide sloshing around west cliff. #MitchellsCove pic.twitter.com/yW2GLnFWzp — Dustin Mulvaney (@DustinMulvaney) January 15, 2022 Monterey Tide Station #Tsunami — Nick Graehl (@nickgraehl) January 15, 2022 #Tsunami observation update: — NWS Tsunami Alerts (@NWS_NTWC) January 15, 2022 Tsunami energy arriving at Del Monte Beach. Wave run up onto the beach is impressive. I'm safely distanced, but I saw other folks have to scramble when the waves unexpectedly reached them. Follow @NWSBayArea for #tsunami safety info. pic.twitter.com/JRl2XsTftI — Brooke Bingaman (@BrookeBingaman) January 15, 2022 Seeing some surges on the Port San Luis tsunami gauge. Reporting up to a 24 cm residual so far. That's 9.4 inches or about 19 inches from the bottom and top of the residual. More at https://t.co/SGd8WQoeji. #tsunami pic.twitter.com/bKYRRXuW4W — NWS Los Angeles (@NWSLosAngeles) January 15, 2022 Another huge surge in the back harbor. Bigger than the first one. #santacruz pic.twitter.com/gzzBmrq9dh — Tim Cattera Photo (@TimCatteraPhoto) January 15, 2022 Strong surge coming in now from #Tsunami in #RichmondCA at Meeker Slough mouth at the Bay. Highest level yet. Wild. pic.twitter.com/fevg14KZrX — Kenya Wheeler (@kenyaw) January 15, 2022 Made it to the high ground edge (6 feet+ above high water level) at Meeker Slough meets the SF Bay. Another observer tells me she has seen two surges already. Check the bridge piling for the high water mark from an earlier surge. pic.twitter.com/Vv8O00SLBF — Kenya Wheeler (@kenyaw) January 15, 2022 So far, business as usual at the Ferry Building, which sits above the expected tsunami surge. High tide in SF is at 9:25. It is probably just my imagination that the bay looks more unsettled this morning. pic.twitter.com/GkkSUSbBgY — Tim Dawson (@timblor) January 15, 2022 As usual, tsunami looks big in Crescent City, CA–waves still incoming. pic.twitter.com/iD0CSBV84O — Jackie Caplan-Auerbach (@geophysichick) January 15, 2022 Here is the current look at Half Moon Bay. You can see Pillar Point Harbor Patrol in the distance. #CaWx #California @sanmateoco @SMHarbor @NWSBayArea pic.twitter.com/z5HHnECtTE — CAL FIRE CZU (@CALFIRECZU) January 15, 2022 #TsunamiAdvisory for #SanFrancisco & #USWestCoast continues. @NWSBayArea reports #tsunami has already resulted in rapid swings up to 3 feet above/below forecast tidal level, or about 6 feet change in 30-60 minute intervals. https://t.co/PDR9BUlsMa #SFwx #CAwx #tongatsunami — Edie Schaffer, CEM (@sf_edie) January 15, 2022 10 AM | Here are the latest observed tsunami wave heights from along the West Coast of the US. Generally tsunami wave heights have been around 1 foot or less along the Oregon and Washington coast. (1/2) pic.twitter.com/r94If9ODXM — NWS Portland (@NWSPortland) January 15, 2022 Video from Cassidy Gillin of waves thrashing near the O’Neill lounge in Santa Cruz. Basic message for the day: don’t be brave. Stay away from the coast @KION546 pic.twitter.com/ieqK9nJ28A — Victor Guzman KION (@VGuzman_TV) January 15, 2022 From a friend at Santa Cruz Harbor @NWSBayArea @Weather_West pic.twitter.com/ZUgfXcbSxw — Dylan (@hamilton4391) January 15, 2022 The landing inundated here is 20 steps up. pic.twitter.com/zfU1XUoMhi — Dustin Mulvaney (@DustinMulvaney) January 15, 2022 This wave climbed up 15 steps higher to the next landing. #CAwx #TsunamiWarning pic.twitter.com/dyRPHjBArP — Dustin Mulvaney (@DustinMulvaney) January 15, 2022 Current look at Surfer’s Beach in El Granada #CaWx #California Stay on higher ground. @NWSBayArea @SMHarbor pic.twitter.com/MMwkMXXr8R — CAL FIRE CZU (@CALFIRECZU) January 15, 2022 The scene at the Santa Cruz Harbor as a tsunami generated tidal surge causing damage Saturday morning #TsunamiAdvisory pic.twitter.com/9ijKU9ZVaK — Vern Fisher (@VFisher45) January 15, 2022 Another surge and it’s now receding once again. Not as high as the first one. #santacruz pic.twitter.com/JIKfhxvZrM — Tim Cattera Photo (@TimCatteraPhoto) January 15, 2022 SURFERS EVACUATED | A surf competition was canceled and surfers were evacuated from the ocean in Santa Cruz due to the tsunami. https://t.co/8sAslNmUko pic.twitter.com/dmfKkEGzFE — KSBW Action News 8 (@ksbw) January 15, 2022 Here's the latest observed heights over tidal predictions along the West Coast pic.twitter.com/qj6pcrIS5r — NWS Eureka (@NWSEureka) January 15, 2022 The tsunami advisory remains in effect. High tide occurred through the morning, and total water levels are decreasing, lowering risk of coastal flooding, but rapid fluctuating surges of water onto and off of the coast/strong currents will continue thru the remainder of the day. pic.twitter.com/5ylsGGvr0m — NWS Bay Area (@NWSBayArea) January 15, 2022 #TSUNAMI water is literally draining out of #ventura harbor. @KTLAnewsdesk @KCBSKCALDesk @KEYTNC3 @vcstar @ABC7Desk @WeatherNation @805Weather @Weather_West @NWSLosAngeles pic.twitter.com/Tjccw1k613 — FireOFire (@FireOFire) January 15, 2022 Here are the latest maximum observed wave heights. Highlights for our area include 3.7 feet at both Crescent City and Arena Cove. The advisory continues for the West Coast, stay tuned to the latest updates on the advisory from @NWS_NTWC pic.twitter.com/UYwFWWLGWd — NWS Eureka (@NWSEureka) January 15, 2022 @Ocean_Networks #knowtheocean sensors tracked the Tonga tsunami wave as it travelled across 🇨🇦’s offshore lands. Data also provided to @NOAA tsunami alert system. pic.twitter.com/MMfjvUrM3b — Dr. Kate Moran (@katemoran) January 15, 2022 Soquel Creek in Santa Cruz flowing *backwards* because of a tsunami 🤯 pic.twitter.com/JxFsllhhdX — robwormald (@robwormald) January 15, 2022 This is from up Soquel Creek pic.twitter.com/ySRF6Okh8o — Kristen (@KRice7) January 15, 2022 #ventura #TsunamiAdvisory #tsunamitonga pic.twitter.com/JqTOqZk9Yf — MJ (@mbearwoman) January 15, 2022
#TsunamiReport for #Tonga #Tsunami recorded on @NOAA tide gages in #California #TongaTsunami #TongaEruption pic.twitter.com/wV6FThMELO — Jason "Jay" R. Patton (@patton_cascadia) January 19, 2022 Tsunami surge up the mouth of San Luis Creek at Avila Beach (Port San Luis) #tsunami — Brian Olson (@mrbrianolson) January 21, 2022 Santa Cruz Harbor back on solid footing post-tsunami, but long-term repairs loom https://t.co/uh5iiPMA8j <– Max Chun with the update on @SantaCruzHarbor after Saturday's #tsunami pic.twitter.com/8kryBrCfc5 — Lookout Santa Cruz (@LookoutSCruz) January 21, 2022 Neskowin, Oregon this morning! #tsunamitonga #TSUNAMI pic.twitter.com/YQJjaFL5w1 — retelling•the•recipe (@tiggirltk) January 15, 2022 #tsunami in #DepoeBay pic.twitter.com/aknFfQkRnk — jim (@jimfromoregon) January 15, 2022 1145 AM Update | The largest waves have spared much of the Oregon Coast so far. Tsunami wave observations so far include… 24 cm (.8 ft) at Charleston, OR (1/2) — NWS Portland (@NWSPortland) January 15, 2022 Unexpected #Tsunami #HungaTongaHungaHaapai #Tsunami #Tonga #Earthquake pic.twitter.com/p16v9c0zLt — Journalist Siraj Noorani (@sirajnoorani) January 15, 2022 Stay safe everyone 🇹🇴 pic.twitter.com/OhrrxJmXAW — Dr Faka’iloatonga Taumoefolau (@sakakimoana) January 15, 2022 The #HungaTongaHungaHaapai eruption is showing up in the tide gauge records at Suva, Apia, Rarotonga and Funafuti. Below is the real time data for the Suva tide gauge. https://t.co/2qBzfVsSJz pic.twitter.com/DXeccmsNw2 — Murray Ford (@mfordNZ) January 15, 2022 Tide gage in American Samoa registering the tsunami created by the Tonga submarine volcanic eruption. Peak amplitude so far is 0.74 meter (~2.5 feet). pic.twitter.com/ATsmnP5clg — Brian Olson (@mrbrianolson) January 15, 2022 ~ 2 Meter #Tsunami in Nuku'alofa, Tonga nach der erneuten heftigen Explosion des Hunga Tonga-Hunga Ha'apai Vulkans. Die ersten Wellen haben auch Fidschi erreicht. Ich hoffe, die seit gestern bestehende Tsunami-Warnung wurde ernst genommen https://t.co/akfdQqtrP7 pic.twitter.com/b90hbS4oTW — Jens Skapski (@JensSkapski) January 15, 2022 For any New Zealand tsunami updates during the Tonga Hunga Tonga-Hunga Ha'apai eruption go here: https://t.co/y020MigfFn — Dr Janine Krippner (@janinekrippner) January 15, 2022 Here are @BOM_au’s latest observations on the waves #Tonga #tsunami 👇 While a 1m wave might not sound big, tsunami have much longer periods (the time between each wave) than wind waves so even a 1m wave can cause significant damage and flooding! pic.twitter.com/27DoahlJEb — A/Prof Hannah Power (@DrHannahPower) January 15, 2022 And same @BOM_au #Tonga #tsunami data again for #NorfolkIsland. Lots of waves and some very big ones! Worth remembering that a #tsunami is more often a series of waves lasting several hours and not just one wave. https://t.co/YH44vAozIG pic.twitter.com/qNmvPc8akD — A/Prof Hannah Power (@DrHannahPower) January 15, 2022 #TsunamiReport for observations of #Tsunami from Tonga volcanic eruption in #CrescentCity #California for recommendations and updates head to https://t.co/rEduVE2EDc for more information the entire west coast of the USA is under a tsunami advisory pic.twitter.com/PJBwLsS7jN — Jason "Jay" R. Patton (@patton_cascadia) January 15, 2022 The plot shows water level data from Honolulu, Hawaii. It indicates that the tsunami continues to impact the Hawaiian islands at least 7 hours after initial arrival. Expect a similar, long duration event along our coast and bays today. pic.twitter.com/LfaS7O8u3A — NWS Bay Area (@NWSBayArea) January 15, 2022 El Servicio Mareográfico del Instituto de Geofisica de la UNAM, muestra que el puerto de #Manzanillo, #Colima muestra el arribo de las olas del #tsunami. pic.twitter.com/nYPJRck9N2 — Alejandro S. Méndez ⚒️ (@asalmendez) January 15, 2022 Muy buena foto !! Interesante comparar los efectos con lo que observa el mareógrafo. Este indica 40 a 60cm de desviación respecto de valores medios. El tsunami sigue en desarrollo. Gracias !! pic.twitter.com/f4WzPs2sMn — Luis Donoso (@Geo_Risk) January 15, 2022 16日午前0時半前、津波注意報が出されている高知県土佐清水市の港の映像からは、海面が上下するのにあわせて係留されている船がゆっくりと上下したり左右に揺れたりしている様子が確認できます。https://t.co/5plmIcphz6#nhk_video pic.twitter.com/2spq3znm6c — NHKニュース (@nhk_news) January 15, 2022 WATCH: Tsunami from Tonga's volcano eruption causes flooding in northern Chile pic.twitter.com/SQ8wtnM06i — BNO News (@BNONews) January 15, 2022 Small but powerful #tsunami surges reached Currarong Creek on NSW south coast between 7-8am this morning pic.twitter.com/7BteF0fhg2 — Casey Kirchhoff (@gumnut_case) January 15, 2022 😲 this video is pretty crazy.. shows the #Tsunami pushing the water up canals in #Chile 🇨🇱 Shows the power of the ocean.. 🎥 @SouthPatriotCL #Tonga #Chili #HungaTonga #HungaTongaHungaHaapai #MotherNature #TsunamiWarning #SouthAmerica pic.twitter.com/FUBzMRws12 — Bryce Campbell🤷🏻♂️ (@BCampbell_24) January 15, 2022 🌊 #Tsunami …sea is receding at Playa de Los Molles in the Valparaíso region of #Chile 🇨🇱 in South America 🤯 🎥 @AgenciaQuinta #HungaTongaHungaHaapai #MotherNature #TsunamiWarning #NationalTsunamiWarning #Earthquake #TsunamiAdvisory #SouthAmerica pic.twitter.com/4X0PVMZLtD — Bryce Campbell🤷🏻♂️ (@BCampbell_24) January 15, 2022 Footage from Niue… crazy sea activity at Sir Robert’s Wharf, Alofi Bay following the #HungaTonga volcanic eruption.. 🌊 🇹🇴#Volcano #Tonga #HungaTonga #HungaTongaHungaHaapai #underwater #Tsunami #Oceania #MotherNature pic.twitter.com/Qptj4yf36q — Bryce Campbell🤷🏻♂️ (@BCampbell_24) January 15, 2022 Timelapse video of the #tsunami taken at Mogareeka inlet at 7-7:20am this morning. Tide is rising (flow left to right) but here is what happens as the waves come through. Mogareeka is usually very flat so the effects are amplified @anuearthscience @ourANU pic.twitter.com/y00Tj1iFb3 — Louis Moresi (@LouisMoresi) January 15, 2022 Urgente Marejadas destruyeron otro muelle en Las Coloradas sector Isla del Rey comuna de Corral, los ríos. — (@EarthquakeChil1) January 15, 2022 A #tsunami is occurring. Tsunami Advisories have been ended for portions of Southcentral and Southeast Alaska- they continue elsewhere. See https://t.co/npoUHxWBas for the latest. — NWS Tsunami Alerts (@NWS_NTWC) January 15, 2022 Some first pics coming out of #Tonga post #Tsunami #volcanoEruption This is in the outer islands Pangai, Haapai. Roads ripped up. Seems some of those massive chunks are pieces of the seawall. #tongatsunami #TongaVolcanoEruption — Josephine Latu-Sanft (@JoLatuSanft) January 16, 2022 https://t.co/Xw7BUtepv4 article with early news about what is happening inside Tonga. Communications are difficult. Tonga volcano: Photos and video give first glimpse of tsunami's impact https://t.co/j5LDZ3B6lP — Dr. Eric J Fielding, PhD (@EricFielding) January 16, 2022 We knew there would be tragedy associated with this event, but seeing it is dreadful. My thoughts are with the Tongan people. https://t.co/eFSbDYRzWE — Jackie Caplan-Auerbach (@geophysichick) January 17, 2022 1Hz microbarograph data from the @geoscope_ipgp seismographic station at Tamanrasset, Algeria https://t.co/2UcaNmFzvShttps://t.co/8PeWmn2OxL pic.twitter.com/tVyMeCnWZV — Anthony Lomax 😷💉🇪🇺🌍 (@ALomaxNet) January 17, 2022 Eruption update: Parts of the Hunga Tonga-Hunga Ha'apai conjoined island that sat atop the largely underwater volcano could be seen via satellite. In December, the eruption caused it to expand in size. Just prior to the blast, it shrank again. Today? It's all but vanished. https://t.co/k5IjZLq5cE — Dr Robin George Andrews 🌋 (@SquigglyVolcano) January 17, 2022 1/n Lot of damages and very complicated aftermath in Tonga islands. — Robin Lacassin (@RLacassin) January 18, 2022 Offical announcement from the Government of Tonga. Tragically, 3 people confirmed to have died. Also, while there are many satellite images coming out showing the awful eruption impact, please be compassionate and considerate to those impacted or awaiting news of loved ones. https://t.co/Vw2SfHEHjh — Mark Tingay (@CriticalStress_) January 18, 2022 Here is a map depicting damage in the islands of #Tonga from the huge eruption of Hunga Tonga-Hunga Ha’apei #volcano, derived from #sentinel1 #sar data. Our hearts are with the people of Tonga. More information and kml at https://t.co/uxKeZHJ0ix pic.twitter.com/shEl0xOV33 — EOS Remote Sensing (@eos_rs) January 18, 2022 .@patton_cascadia @VolcanoSimon 🤔 Can @CopernicusEU #Sentinel1 wave field and timing tell us any thing about what may have happened underwater around Hunga Tonga ? https://t.co/8yNbj5Lk0x — DPManchee (@DPManchee) January 19, 2022 Three days after the disastrous eruption of the #HungaTonga #volcano, #Tonga is still isolated@CopernicusEMS has been activated ⬇️The effects of the explosion on Nomuka Island are visible when comparing the #Sentinel2 🇪🇺🛰️images of — 🇪🇺 DG DEFIS #StrongerTogether (@defis_eu) January 18, 2022 Distance was no barrier to providing critical real-time #tsunami data following Saturday's #TongaEruption. 9000km from this rare underwater #volcano event, our #UVic #knowtheocean sensors informed @NWS_PTWC alerts and will inform future research. Read: https://t.co/FPECte9dP1 pic.twitter.com/DJX6z2pUPp — Ocean Networks 🇨🇦 (@Ocean_Networks) January 19, 2022 🇹🇴The miracle survival of a 57-year-old disabled man who survived in the ocean for 27 hours after being swept away by a tsunami wave is one of the first astonishing accounts to emerge from Tonga Thread🧵👇https://t.co/m5uaVTFnoT pic.twitter.com/87n3TUs0T0 — Telegraph World News (@TelegraphWorld) January 20, 2022 This map, based on #alos2 #sar satellite data, shows the devastating impact of the huge #Tonga volcanic eruption. Damaged areas are marked by yellow to red pixels, with red indicating the most damage. More info, GeoTIFF and KMZ files at https://t.co/uxKeZHJ0ix pic.twitter.com/2xSSZeYVbH — EOS Remote Sensing (@eos_rs) January 23, 2022 — Ailsa Naismith (@AilsaNaismith) February 1, 2022 Quite the day at the beach sampling the January 2022 Hunga tsunami deposits- if you squint there are ?3 slightly different grainsize layers here – plus thin black layer of ash near the top, western Tongatapu pic.twitter.com/oZcEPGxeO6 — Shane Cronin (@scronin70) April 6, 2022 Extracting oriented tubes of tsunami deposits will help colleagues figure out deposition histories using 3D magnetic and textural properties- Hunga tsunami deposits – western Tongatapu pic.twitter.com/ojcoi9kiSP — Shane Cronin (@scronin70) April 6, 2022 Tonga tsunami, quite impressive that it propagated all the way to stations in the coast of Mexico (Manzanillo over 1.4m) and California… Here is a order one attempt to model this tsunami @geosmx #geoclaw pic.twitter.com/drzz5GMHJK — angel ruiz (@angelruizangulo) January 15, 2022 Ash plume extent update for Hunga Tonga-Hunga Ha'apai eruption in Tonga. — Dr Janine Krippner (@janinekrippner) January 15, 2022 Truly incredible imagery from the Himawari meso sector of multiple shockwaves from a volcanic eruption on Tonga propagating through what was recently subtropical storm Cody. My back of the napkin math estimates put the shockwave speed somewhere in the vicinity of 500-600 mph. pic.twitter.com/lDyNXFpLbE — Isaac Schluesche (@SlushyWx) January 15, 2022 Find the eruption. 🌋 pic.twitter.com/0xUWE8spzh — Brian Brettschneider (@Climatologist49) January 15, 2022 Tonga's Hunga Tonga volcano just had one of the most violent volcano eruptions ever captured on satellite. pic.twitter.com/M2D2j52gNn — US StormWatch (@US_Stormwatch) January 15, 2022 This volcano eruption is producing some sights we won't see on satellite for a while after. The explosive updraft powers right into the stratosphere, and the warming with height there makes the blob appear warm/shallow. There's also the shockwave and condensation pushing NE pic.twitter.com/6ud79uws9w — Alex Boreham (@cyclonicwx) January 15, 2022 1.14.2021: Large volcanic eruption near Tonga (Hunga Tonga-Hunga Ha'apai volcano) today as seen from outer space. Shown on visible imagery using the Himawari satellite. #hiwx #tsunami #earthquake pic.twitter.com/zOTj6Qu1Wv — NWSHonolulu (@NWSHonolulu) January 15, 2022 Shock wave from the big eruption of Hunga-Tonga-Hunga-Ha'apai today seen on @raspishake infrasound station in Auckland. Time on bottom is UTC+8 – add 5 hours to get local time in New Zealand. pic.twitter.com/e6Ns7gLGS7 — Mark Tingay (@CriticalStress_) January 15, 2022 Fantastic #infrasound signals on the Australian IMS arrays from the #Tonga #volcano. Data courtesy of @GeoscienceAus and made available via @IRIS_EPO – these atmospheric waves travel much slower than seismic waves and over an hour separates the signals on mainland Australia. pic.twitter.com/7A8KUZdA22 — Dr. Steven J. Gibbons (@stevenjgibbons) January 15, 2022 The pressure wave from the Hunga Tonga-Hunga Ha'apai eruption arrived here in Anchorage at 3:30 a.m. AKST. This is exactly 7 hours after the eruption. The volcano is 5,820 miles away (9,360 km). That means it travelled at 830 mph (1,340 kmh). pic.twitter.com/R3rgzAbo6r — Brian Brettschneider (@Climatologist49) January 15, 2022 Seismogram from Monasavu, Fiji ~800km NW of Hunga Tonga-Hunga Ha'apai eruption. Assuming main eruption at ~04h15mUTC, shows P waves, seismic surface waves (Lq, Lr) and oceanic SOFAR acoustic waves (T). Signal from the eruption continues for 2+ hours.https://t.co/etU65z1wyq pic.twitter.com/2PublssOYm — Anthony Lomax 😷💉🇪🇺🌍 (@ALomaxNet) January 15, 2022 A number of folks have posted similar obs, but here are two pressure traces showing the #HungaTongaHungaHaapai shock wave observed at UNR in Reno and UoU in Salt Lake City this morning. The SLC data seem to show subsequent oscillations (sloshing) in the valley cold pool. #UTwx pic.twitter.com/ekDRXUUrq8 — Neil Lareau (@nplareau) January 15, 2022 A similar pressure bump was observed in Portland, Oregon early this morning as well. See the right hand column in the attached 5 minute data from the Portland Airport. #ThePowerOfTheVolcanoEruption #pdxtst #orwx #wawx https://t.co/ITFTtfbEwM pic.twitter.com/T2dXs2zqf5 — NWS Portland (@NWSPortland) January 15, 2022 Here's the latest eruption. Again ice detectable. This time ash signal appearing. Plume appears to be significantly stronger than the last one. I've set the colour bar and scale to try to highlight the tropospheric and stratospheric portions of the plume (top left plot). pic.twitter.com/zRaFvG2jvJ — Andy Prata (@andyprata) January 15, 2022 6 hours of infrared satellite in 4 seconds. You can see the atmospheric shock wave ripple out Pacific-wide after the initial #eruption in #Tonga (quite hard to see but it crosses #Hawaii and #Australia). People as far away as Southland in #NewZealand reported hearing the booms. pic.twitter.com/a0YHx4Q0q0 — WeatherWatch.co.nz (@WeatherWatchNZ) January 15, 2022 A @planet SkySat image appears to have been acquired ~2 hours *before* the 04:00 UTC 15 Jan 2022 #HungaTongaHungaHaapai. The whole central part of the island was missing, probably blown up in the 14 Jan 2022 explosions. @janinekrippner @SmithsonianGVP @rsimmon pic.twitter.com/5Vtuu1fOvV — Raphael Grandin (@RaphaelGrandin) January 15, 2022 #Tonga 🇹🇴🌋 Antes y después #HungaTongaHungaHaapai Una reciente imagen tomada por los satélites de #SkySat propiedad de Planet Labs. muestra que el corredor de tierra que existía desde 2014 entre las islas desapareció después de las erupciones cataclísmicas de ayer. pic.twitter.com/2fM8rwNPZS — Alejandro S. Méndez ⚒️ (@asalmendez) January 15, 2022 That map, created with April 2016 data from the R/V Falkor, showed details of the overall volcanic edifice. Measured on this quick Google Earth overlay, the diameter of the caldera rim is ~6 km. Recent eruptions have been on the N and NE sides. Red * is 2009 vent. pic.twitter.com/oPdKMR44G3 — Global Volcanism Program (@SmithsonianGVP) January 15, 2022 We now have some one-minute infrared imagery of the ongoing eruption, via GOES-17. pic.twitter.com/ZxdhVqxWqU — Dakota Smith (@weatherdak) January 15, 2022 Jumping on board pressure perturbation Twitter to share this animation of @okmesonet pressure data. Several pressure waves created by the Hunga Tonga–Hunga Ha'apai volcano eruption in Tonga passed from southwest to northeast across Oklahoma between 7 and 9 AM CST this morning. pic.twitter.com/aBpRXNbNeX — Tim Supinie (@plustssn) January 15, 2022 Shockwave from the #HungaTongaHungaHaʻapai eruption visible as an abrupt pressure change across the @UVicSEOS Climate Network at about 4 a.m. this morning https://t.co/J6FhLuG6C6 @edwiebe @AJWVictoriaBC @UVicScience pic.twitter.com/LIowFgAssj — Dr. Edwin Nissen (@faulty_data) January 15, 2022 A Planet SkySat captured an image of Hunga-Tonga Hunga-Ha’apai today at 2:25 UTC, just two hours before its violent eruption that triggered a tsunami. Read @tanyaofmars' latest blog for more details on our monitoring of the volcano: https://t.co/8MdAAnopeK pic.twitter.com/RG68ADVSEV — Planet (@planet) January 15, 2022 Tonga tsunami is arriving at BC! Last twelve hours of seafloor pressure data show: Series of waves, starting to arrive at @Ocean_Networks stations at 8:22 PST, and at the west coast about 9 AM PST. Height about 5 cm offshore. Coastal currents probably a bigger issue. #BCTsunami pic.twitter.com/VpEzXymHB3 — Martin Scherwath (@mscherwath) January 15, 2022 1-min CG lightning plot of #Tonga eruption pic.twitter.com/Dt0exOhvG7 — William Churchill (@ChurchillWx) January 15, 2022 Tonga Volcano eruption heard from Lakeba, Fiji 😢🇹🇴 #TongaVolcano pic.twitter.com/qc9ISL25QX — Portia Dugu (@portiajessene) January 15, 2022 Ionospheric total electron content (TEC) perturbations derived from a GNSS site on Samoa from the Hunga Tonga eruption were not small to say the least @IGSorg pic.twitter.com/bMa8MKCZ3o — Brendan Crowell (@bwcphd) January 15, 2022 Huge volcanic eruption near Tonga. Reports of tsunami there and it's gone pitch black. Lots of lightning too. #tonga pic.twitter.com/Eia4fidPRc — Rick Threlfall (@RickThrelfall) January 15, 2022 Putting the #Tonga #eruption into perspective. It's an astonishing event. Link to story/infographics here: https://t.co/HLIzcRI8eMhttps://t.co/Pm2OWgcGPf pic.twitter.com/oUrc71jcJf — WeatherWatch.co.nz (@WeatherWatchNZ) January 15, 2022 15 minute pressure altimeter change via ASOS NWS/MADIS 5 minute interval data. Shows the shockwave from the #Tongaeruption , feel free to use as you wish. pic.twitter.com/P31Aq1SYku — daryl herzmann (@akrherz) January 15, 2022 Longwave infrared channel via #GOESWest of the #Tonga eruption.. one of the most incredible satellite animations I've ever seen. The relative warmth of the ash cloud atop the very cold tropospheric convective anvil. Waves upon waves. Simply incredible. pic.twitter.com/MoBcIxkblW — William Churchill (@ChurchillWx) January 15, 2022 New data alert 🚨 We just overflew Hunga Tonga-Hunga Ha'apai volcano with #Sentinel1 🛰️🌋 The datatake didn't include #Tonga main island, where I desperately hope everyone is safe 🇹🇴❤️🩹Here's our last 3 passes over the volcano… pic.twitter.com/KD39030U5S — Thomas Ormston (@ThomasOrmston) January 15, 2022 <トンガの火山噴火の衝撃波か> — ウェザーニュース (@wni_jp) January 15, 2022 The evolution of the volcanic island of Hunga Tonga over time, with the last image having been taken just two hours before the massive eruption last night. Curious to see the scene after that… Images from Google Earth and @planet. pic.twitter.com/lOmca4Du7I — Alex Spahn (@spahn711) January 15, 2022 This is the most incredible #lightning loop that I have ever put together. #HongaTongaHungaHaapai #HungaTonga #Volcano eruption today with nearly 400k lightning events in just a few hours! pic.twitter.com/xqW70NLeVd — Chris Vagasky (@COweatherman) January 15, 2022 Looks to me like we see the seismic signal from the Tonga eruption at Weston, MA and Westport, CT. — Alan Kafka (@Weston_Quakes) January 15, 2022 Is it possible that we see pressure changes in Slovakia too? Graphs time UTC+1. pic.twitter.com/jD0gy3iflc — Blažej Krajňák (@BlazejKrajnak) January 15, 2022 Before and after photos show that the island of Hunga Tonga and Hunga Ha'apai is essentially gone following the explosive eruption of the volcano last night. https://t.co/6GvI5nNGV2 pic.twitter.com/wEjBhfmWFZ — Kaylan Patel (@WxPatel) January 15, 2022 If this estimation is correct, this is huge!!! https://t.co/7VKIsj5ovQ pic.twitter.com/NM5qeqeccB — Sarah Lambart (@Sarah_Lambart) January 15, 2022 A lot of talk about just how big the eruption at Hunga Tonga-Hunga Ha'apai was. It might be awhile before we know & we don't know if there is more to come. Questions abound about what caused the tsunami, why the eruption was so explosive, etc https://t.co/oXas1XevjC @DiscoverMag — Dr. Erik Klemetti Gonzalez (@eruptionsblog) January 15, 2022 With latest satellite imagery, we get a step closer to understand what happen with Hunga #Tonga leading to this ocean-wide #tsunami. Latest @sentinel_hub imagery shows the loss of a majority of the volcano's emerged landmass. However, most of its structure lies underwater. pic.twitter.com/odz5VcNphl — Andreas Schäfer (@DrAndreasS) January 15, 2022 The first #stratospheric #volcanic #eruption of 2022, at #HungaTongaHungaHaapai (#Tonga) on Jan 13-14. #Sentinel5P #TROPOMI & @NASA's Aura/OMI both measure ~0.05 Tg SO₂ in the #volcanic cloud – not enough for #climate impacts. @CopernicusEU @NASAEarth @volcanessa @MetService pic.twitter.com/f9tx76Z4Ow — Prof. Simon Carn (@simoncarn) January 15, 2022 Here’s a seismic record section of the Tonga volcanic eruption that’s causing the tsunami in the Pacific basin (h/t NEIC) pic.twitter.com/sljldhPFmh — Bill Barnhart (@SeismoSARus) January 15, 2022 Atmospheric wave response to Tonga eruption, from 4 UTC to 10:50 UTC. Slightly smoothed 10-minute change in GOES-17 band 13 (IR). Looks like some modest filtering would pull out a really clear signal. pic.twitter.com/CHZY7iv4HH — Dr. Mathew Barlow (@MathewABarlow) January 16, 2022 There are a lot of questions about VEI (Volcano Explosivity Index). I recognize that the want to compare this eruption is there, but there is so much information that we simply do not have. — Dr Janine Krippner (@janinekrippner) January 16, 2022 Pressure wave #2 passed here last night at about 11 p.m. This is the wave travelling from the opposite direction. Still had an impressive magnitude. pic.twitter.com/1fG4aKhWqs — Brian Brettschneider (@Climatologist49) January 16, 2022 Trying to understand why the weather stations at Stornaway on the Outer Hebrides measured the blast before us. Basically because the blast came from the north. Unbelievably the shortest distance between here and the South Pacific is over the North Pole. 🤯 #TongaVolcanoEruption pic.twitter.com/6MdZVJ4VWI — Dr David Boyce (@DrDavidBoyce) January 15, 2022 GNSS recordings (cm) at the IGS station TONG on the Tonga island by PRIDE PPP-AR (https://t.co/JOTbaSVeRq) during the Hunga Tonga volcano eruption on Jan 15, 2022. pic.twitter.com/tkNJd2mceC — Jianghui Geng (@GengJianghui) January 16, 2022 It appears that there is some minor activity ongoing at Hunga Tonga-Hunga Ha'apai, as expected. This is based purely on satellite data. No volcanic lightning detected.https://t.co/13uhR0353u — Dr Janine Krippner (@janinekrippner) January 17, 2022 Why does it take awhile to get satellite images of what's going on in #Tonga? We have to wait for satellites to fly over, or redirect them. Also, they "see" in different wavelengths, so night, clouds, and ash can obscure the view. But we should have updates soon! https://t.co/hWpCN8fe4R — Dr. Judith Hubbard (@JudithGeology) January 17, 2022 In Germany two main air pressure waves from the #Tonga eruption could be detection: The first wave traveled from north to south, while the second wave moved from south to north. The reason might be explained by the animation below, where I visualized an outgoing circular wave… pic.twitter.com/B57uRyy3ik — StefFun (@StefFun) January 16, 2022 A news story about Tonga. Most of the news in the U.S. is very American-centric, so you have to poke around the int’l news scene to get any news about Tonga.https://t.co/GXZlAIlsrQ — Pete R. Girguis (@pgirguis) January 16, 2022 Displacements measured at GPS/GNSS station TONG in Tonga about 70 km from #HungaTongaHungaHaapai shows large motion over about 10 minutes that returns close to previous position. Some kind of shock wave or seismic wave, probably. https://t.co/7Bpq2U8GsN — Dr. Eric J Fielding, PhD (@EricFielding) January 16, 2022 Copernicus Sentinel-1A radar imaged #HungaTongaHungaHaapai on 15 January 2022 after major eruption. Most of two islands and entire new cone was blown away, along with reef south of underwater caldera. @googleearth Engine HV radar polarization animation Aug-Jan by @TheHandwerger pic.twitter.com/gwnA52Q12e — Dr. Eric J Fielding, PhD (@EricFielding) January 17, 2022 So the Hunga Tonga and Hunga Ha'apai were two separate islands before an eruption in 2014-15, and they split up before the violent eruption last Saturday. And now, very little of the two islands are left. pic.twitter.com/5G7Zy3n0td — Annie Lau (@AYAnnieLau) January 17, 2022 SNPP/OMPS limb-profiler (OMPS-LP) aerosol vertical profiles from Jan 16 shown below captured the stratospheric #volcanic aerosol cloud reaching altitudes up to ~30 km (in same location as the highest SO₂ columns). h/t @NASAGoddard Ozone & Air Quality teamhttps://t.co/PBUPJCgEtJ pic.twitter.com/3eNIwouCfs — Prof. Simon Carn (@simoncarn) January 17, 2022 Don't know if anyone has plottet something similar already. — Felix Eckel (@FelixEckel) January 16, 2022 A THIRD pressure anomaly associated with the #TongaVolcano passed through #Miami on Sunday evening… the timing means that it was the first wave making a full trip around the globe! Absolutely mind-blowing power. pic.twitter.com/lpW9FY97Mw — Brian McNoldy (@BMcNoldy) January 17, 2022 Sure looks like we got a fourth passage of the Hunga Tonga – Hunga Ha'apai eruption shockwave in Utah. Timing is spot-on and signal is similar to previous passages. Interesting for sure but worried for the people of Tonga. pic.twitter.com/ZzZzTrIJcH — Michael Bunds (@cataclasite) January 17, 2022 Revisiting the Tonga volcanic shockwave: Here's the latest Eureka barograph showing the 1st shockwave, another distinctive shockwave just after midnight Sat night (the other side of the initial shockwave), & another possible shockwave just after noon today. #CAwx #Tongaeruption pic.twitter.com/c4bXjPcZrY — NWS Eureka (@NWSEureka) January 18, 2022 I’ve tried to annotate this here to help folks understand what it shows. pic.twitter.com/lCtuc4svaS — Mark Tingay (@CriticalStress_) January 18, 2022 The @EOS_SG blog post on the Hunga Tonga-Hunga Ha'apai eruption is up! Featuring the infrasound signal from the eruption as recorded in Singapore https://t.co/YMD56WZpqY — Anna Perttu (@InfraSaurus) January 18, 2022 I took a quick dive into the science of the volcanic eruption in Tonga. It was an extraordinary event that will keep researchers busy for a while… #TongaVolcano https://t.co/K0K3aQUv3s — Henry Fountain (@henryfountain) January 19, 2022 #HungaTonga #HungaTongaHungaHaapai #volcano #eruption effect on the #atmosphere thermal structure — Riccardo Biondi (@Richi_Biondi) January 19, 2022 Pressure waves from #HungaTongaHungaHaapai have travelled 3 times around the globe as of this morning. This pressure graph is from Iceland. It shows 6 peaks rather than just 3 because.. 1/n pic.twitter.com/W4WMOYswSV — Dr. Evgenia Ilyinskaya (@EIlyinskaya) January 19, 2022 Can we use the infrasound recordings of the #HungaTongaHungaHaapai eruption to estimate origin time and average sound velocity? Let's try with a semblance approach of the first arrival. Traces are time corrected for distance and velocity and stacked. pic.twitter.com/vjiqFLvmNm — Felix Eckel (@FelixEckel) January 20, 2022 Garvin et al. (2018) Fig.3 https://t.co/2MPkw4AGRe にある海底地形図をSentinel-2の衛星写真にジオリファレンスしてみた。黄色塗りつぶし箇所: 噴火後の島(17-Jan.) 黄色点線箇所: 噴火前の島(2-Jan.) pic.twitter.com/xcUtnVPJYv — F. IKGM🌏地球科学ニュース速報モード (@geoign) January 20, 2022 .@CopernicusEU @patton_cascadia @BBCAmos @Ifremer_fr @remi_wnd Wooooh ! Looks like #Sentinel1 Wave Mode products also caught the tsunami waves 🧐 – these from @Ifremer_fr XWaves The power of earth observation. pic.twitter.com/Dz3MCfFvmf — DPManchee (@DPManchee) January 20, 2022 Almost everything about Tonga's recent volcanic eruption has left scientists scratching their heads, from the sonic boom to the baffling tsunami. And it all happened from about an hour of volcanic fury. I dig into the many mysteries @NatGeohttps://t.co/y14NIIzEtk — Maya Wei-Haas, Ph.D. (@WeiPoints) January 20, 2022 (1/4) #CTBTO continues to analyze data from the Hunga Tonga-Hunga Ha'apai volcanic eruption. In terms of infrasound technology only, this is the largest event ever recorded by the #IMS infrasound network; much larger than the Chelyabinsk meteor in 2013. pic.twitter.com/T7y9Nk9Rhm — CTBTO (@CTBTO) January 21, 2022 #Copernicus for #volcano monitoring The eruption of the #HungaTonga volcano has released large amounts of SO2 into the atmosphere #Sentinel5P 🇪🇺🛰️captured the journey of the SO2 plume over Australia and the Indian Ocean ⬇️ Data from 15 January (before the 🌋) to 20 January pic.twitter.com/gDGUnilrvh — Copernicus EU (@CopernicusEU) January 22, 2022 衝撃波による津波,meteotsunamiというようです.今回のトンガの噴火はわからないことだらけです.長い記事ですが興味深いです.https://t.co/eye6fhiq3k — 遠田晋次 (Shinji Toda) (@EeWkKI8KqQLHUqz) January 22, 2022 Hunga Tonga, les travaux des communautés du pôle Terre solide de @dataterra #TongaVolcanoDataTerra: évolution de la morphologie de l'île volcanique avant et après l'explosion du 15/01 vue par satellite. Destruction de 90 % de l'île. https://t.co/kJhqZjVRtO pic.twitter.com/VM48FaQuMI — ForM@Ter (@ForMaTerre) January 25, 2022 The low-frequency signal from the Hunga Tonga-Hunga Ha'apai vulcanic eruption that generated the tsunami (15/01) was well captured by >400 #BMKG broadband seismic stations over the Indonesia region. The vertical record from five selected stations (bandpass filtered 0.01-0.05 Hz): pic.twitter.com/k2D3M6zClL — Dimas Sianipar (@SianiparDimas) January 27, 2022 Island nation of #Tonga is completely offline following a #tsunami triggered by a massive volcanic eruption in the Pacific Ocean. According to @kentikinc data, traffic volumes began to drop around 4:30 UTC (5:30pm local) before finally going to zero at 5:40 UTC (6:40pm local). pic.twitter.com/g4QZilBrd5 — Doug Madory (@DougMadory) January 15, 2022 Tonga shock wave converges and rebounds from antipodal point in North Africa. Faster than other animation because the wave front is harder to see. EUMETSAT IR data, 18 UTC 15 Jan – 2 UTC 16 Jan, 15-minute differences. pic.twitter.com/b4QHtnpxPd — Dr. Mathew Barlow (@MathewABarlow) January 17, 2022 Shockwave from Hunga Tonga-Hunga Haʻapai eruption plume, seen by pressure change at UK sites. Wave moves southward down the country 18-20Z 15Jan. The same wave, but travelling the other way around the globe, moves northward up the country 01-03Z 16Jan. @RoostWeather @Silkstiniho pic.twitter.com/2jXaWwyzih — Will Thurston (@imthursty) January 16, 2022 "The waves are red because of airglow, an aurora-like phenomenon caused by chemical reactions in the upper atmosphere. Airglow is usually too faint to see, but gravity waves from the volcano boosted the reaction rates." https://t.co/nntTFiBOrE https://t.co/qWinu9InSV — Justice (@Loveon999) January 18, 2022 Tonga volcano : This is shockwave as measured with the IASI satellite mission (temperature perturbation between the day of the eruption and the next day). First time we see this ! pic.twitter.com/7uTCwP3tNP — cathy clerbaux (@CathyClerbaux) January 19, 2022 Oopps! When a volcano erupts with such intensity in one part of the world and causes an #oilspill 10.000 km away. The Mare Doricum vessel was offloading at La Pampilla (Peru) refinery when the tsunami hit. Now, one of the worst oil disasters in the region. https://t.co/7nBNtWgX01 pic.twitter.com/MVPFGyIFWe — ᴄʀɪꜱᴛɪɴᴀ ᴠʀɪɴᴄᴇᴀɴᴜ 🌍🛰️ 🇪🇺 (@cavrinceanu) January 21, 2022 First simulation of the atmospheric pressure disturbances generated by the #Tonga volcano explosion compared with observations from different locations. Not bad results for a first guess.@IMEDEA_UIB_CSIC @UIBuniversitat pic.twitter.com/d26wmGiDJY — Angel Amores (@an_amores) January 21, 2022 Intriguing "halo" visible in @capellaspace radar image of #HungaTongaHungaHaapai submarine volcano. 🧐 Image acquired on 21 Jan. 2022 (03:32 UTC). Possible explanations: a/ submarine topography 🌋🌊 b/ winds & currents 💨 c/ residual heat 🔥 Thread! 🧵 (1/15) pic.twitter.com/tQOJj96lHu — Raphael Grandin (@RaphaelGrandin) January 25, 2022 Still going… https://t.co/6UCJJulbMh — Harold Tobin (@Harold_Tobin) January 25, 2022 Gemini Cloudcam Gravity Waves from Earth to Sky Calculus on Vimeo. Below is an interactive map that displays a network of publicly accessible webcams that could be used to observe tsunami waves. I don’t always have the time to write a proper Earthquake Report. However, I prepare interpretive posters for these events.
I don’t always have the time to write a proper Earthquake Report. However, I prepare interpretive posters for these events.
I don’t always have the time to write a proper Earthquake Report. However, I prepare interpretive posters for these events. A few days ago, I was passed out on my couch (sleep apnea) and for some reason I awoke and noticed that I had gotten a CSEM notification of a large earthquake offshore of Alaska. Well, after looking into that, I sent my boss, Rick, a text message: “8.2.” So let’s take a look at the things that may have affected the size of the tsunami from this 2021 M 8.2 earthquake. Below is an educational video from the USGS that presents material about subduction zones and the 1964 earthquake and tsunami in particular. This is a map from Haeussler et al. (2014). The region in red shows the area that subsided and the area in blue shows the region that uplifted during the earthquake. These regions were originally measured in the field by George Plafker and published in several documents, including this USGS Professional Paper (Plafker, 1969).
Above: Rupture zones of earthquakes of magnitude M > 7.4 from 1925-1971 as delineated by their aftershocks along plate boundary in Aleutians, southern Alaska and offshore British Columbia [after Sykes, 1971]. Contours in fathoms. Various symbols denote individual aftershock sequences as follows: crosses, 1949, 1957 and 1964; squares, 1938, 1958 and 1965; open triangles, 1946; solid triangles, 1948; solid circles, 1929, 1972. Larger symbols denote more precise locations. C = Chirikof Island. Below: Space-time diagram showing lengths of rupture zones, magnitudes [Richter, 1958; Kanamori, 1977 b; Kondorskay and Shebalin, 1977; Kanamori and Abe, 1979; Perez and Jacob, 1980] and locations of mainshocks for known events of M > 7.4 from 1784 to 1980. Dashes denote uncertainties in size of rupture zones. Magnitudes pertain to surface wave scale, M unless otherwise indicated. M is ultra-long period magnitude of Kanamori 1977 b; Mt is tsunami magnitude of Abe[ 1979]. Large shocks 1929 and 1965 that involve normal faulting in trench and were not located along plate interface are omitted. Absence of shocks before 1898 along several portions of plate boundary reflects lack of an historic record of earthquakes for those areas.
Proposed tectonic model for southern Chile. Partitioning of the oblique convergence vector between the Nazca plate and South American plate results in a dextral strike-slip fault zone in the magmatic arc and a northward moving forearc sliver. Modified after Lavenu and Cembrano (1999).
In 2016, there was an earthquake along the Alaska Peninsula, a M 7.1 on 2016.01.24. Here is my earthquake report for this earthquake. Here is a map for the earthquakes of magnitude greater than or equal to M 7.0 between 1900 and today. This is the USGS query that I used to make this map. One may locate the USGS web pages for all the earthquakes on this map by following that link. I plot tide gage data for gages in the north and northeast Pacific Ocean. These data are from NOAA Tides and Currents, though are also available via the eu tide gage website here. The scale for the tsunami wave height is on the right side of the chart. Below are surface deformation data generated by the USGS based on their finite fault model. The three panels show surface deformation in the north, east, and vertical directions. 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.
Digitized marigrams from 1938 Alaskan earthquake recorded in Crescent City, San Diego, and San Francisco. The tidal componenht asn ot beenr emoved.S tartt ime listedf or each record is the time in minutes from the origin time of the earthquaketo the startt ime of the digitizedr ecord.
Location of subfaults used in inversion of tsunami waveforms. Graph shows slip distribution in meters.
Observed and synthetic waveforms from inversion for four subfaults. Start time of each record is different. The arrows indicate the parts of the waveforms used for the inversion.
Example slip distributions for two of the slip models, shallow eastern and shallow far eastern. For each model the slip is the product of a function f(x) representing the along-strike variation and g(y) representing the downdip variation, and then scaled to a constant magnitude MW 8.25. The functions f(x) and g(y) are based on relations in Freund and Barnett [1976]. For the central and western models, the rupture area is the same as for the eastern model, but the area of higher slip is shifted to the west. For the mid-depth and deep models, the main area of high slip is shifted downdip.
Vertical seafloor displacements caused by representative slip scenarios. On the left side, the slip is concentrated in the east and the deep, mid-depth and shallow slip distribution scenarios are shown. On the right, the Western, Central and Far Eastern slip distribution scenarios are shown assuming the shallow rupture. Displacements are in meters. Red contours show depth to the plate interface from 0 to 80 km with a 10 km increment.
Tide gauge data and model predictions for the eastern and far eastern source models.
Here is an animation from one of the Ferymueller et al. (2021) models for the 1938 M 8.2 tsunami.
A) Location of Chirikof Island within the plate tectonic setting of the Alaska-Aleutian subduction zone. Rupture areas for great twentieth century earthquakes on the megathrust are in pink. (B) Velocity field of the Alaska Peninsula and the eastern Aleutian Islands observed by global positioning system (GPS) (Fournier and Freymueller, 2007). Colors show inferred rupture areas for earthquakes in 1788 (green) and 1938 (orange). Both A and B are modified from Witter et al. (2014). The section of the megathrust between Kodiak Island and the Shumagin Islands has been referred to as the Semidi segment (e.g., Shennan et al., 2014b). (C) Physiography of Chirikof Island (Google Earth image, 2012) showing the location of our study area at Southwest Anchorage, a prominent moraine, a fault scarp (facing southeast) that probably records the 1880 earthquake, the New Ranch valley reconnaissance core site, and UNAVCO GPS station AC13 (http:// pbo .unavco .org /station /overview /AC13). In the eighteenth and nineteenth centuries, Chirikof Island was known to native Alutiiq and Russians as Ukamuk Island.
Age probability distributions for probable (red) and possible (orange) tsunami deposits at Southwest Anchorage (labels as in Fig. 11) compared with age distributions for possible tsunami deposits at Sitkinak Island (Briggs et al., 2014a) and with age estimates for great earthquakes and tsunamis on Kodiak Island (from studies referenced on this figure; #EarthquakeReport for M8.2 #Earthquake and probable #Tsunami offshore of #Alaskahttps://t.co/mFtEoigFQB read more about the tectonics herehttps://t.co/L4RHgNdex7 pic.twitter.com/Kgp6HxzSQ6 — Jason "Jay" R. Patton (@patton_cascadia) July 29, 2021 From @BNONews — Desianto F. Wibisono (@TDesiantoFW) July 29, 2021 #EarthquakeReport preliminary interpretive poster for M 8.2 #Earthquake #tsunami offshore of #Alaska in region 1938 M 8.2 generated #Tsunami with wave hts 5-10cm in #California (Johnson and Satake, '96)https://t.co/mFtEoigFQB — Jason "Jay" R. Patton (@patton_cascadia) July 29, 2021 Watch the waves from the M8.2 earthquake just offshore Alaska roll across the seismic stations in North America. (Credit @IRIS_EPO) pic.twitter.com/8qQeV4qBZY — Dr. Kasey Aderhold (@KaseyAderhold) July 29, 2021 Here's the #USGS MT for the recent M 8.2 on Fig. 1 of Freymueller et al. 2021 (https://t.co/FN8owbDqEY). Orange outline is aftershocks of the 1938 M 8.2. Red lines are 1 m contours of 1938 slip models. Grey is slip deficit inferred from geodesy. Obvious similarities 1938 -> 2021! pic.twitter.com/DIUh4YVhXc — Rich Briggs (@rangefront) July 29, 2021 UPDATE: The timing and form of this signal looks like it is the DART response to the seismic waves directly from the earthquake, NOT to a tsunami wave. pic.twitter.com/bxeF5TPqjv — Anthony Lomax 😷🇪🇺🌍 (@ALomaxNet) July 29, 2021 Small tsunami waves continue arriving at Sand Point & other coastal areas of Alaska. Tomorrow these waves will create swirly currents in boat harbors up & down the west coast, so tie up your boats real good. pic.twitter.com/nofvKqJoU5 — Brian Olson (@mrbrianolson) July 29, 2021 And since I have a drone workshop to attend tomorrow, I will bow out now and get some sleep. — Jascha Polet (@CPPGeophysics) July 29, 2021 @NOAA Tsunami Warning System has issued a tsunami watch for the West Coast. The warning for Hawaii has been cancelled, because the waves are focused east of Hawaii and the event isn't that large. @NWS_NTWC pic.twitter.com/h2KRBmOKNL — Dr. Lucy Jones (@DrLucyJones) July 29, 2021 A Tsunami Warning remains in effect. A Tsunami Advisory also remains in effect. pic.twitter.com/QLTiROkiri — NWS Anchorage (@NWSAnchorage) July 29, 2021 What a tsunami warning sounds like… they tested this earlier today too but this time is for real! M8.2, looks like on the subduction zone interface. (and look at those pretty peonies! 🌸) pic.twitter.com/1HPy8tBUC2 — Dr. Kasey Aderhold (@KaseyAderhold) July 29, 2021 Records of tsunami deposits show significant tsunamis in 1788, 1880 and 1938 (https://t.co/NsFfTuqigs), indicating recurrence intervals of large earthquakes in the Semidi segment every 58-92 years. We are now 83 years since 1938, so that seems roughly consistent. pic.twitter.com/CGIM40Fv0g — Dr Stephen Hicks 🇪🇺 (@seismo_steve) July 29, 2021 #EarthquakeReport for M 8.2 #Earthquake and #Tsunami offshore of #Alaska updated poster with Sand Point tide gage data@USGS_Quakes slip model — Jason "Jay" R. Patton (@patton_cascadia) July 29, 2021 Preliminary finite fault for this morning's M8.2 earthquake is available. Rupture primarily to the NE of the hypocenter, away from the Shumagin Gap.https://t.co/dVkYuR2kPC pic.twitter.com/idGBqxRhbX — Dr. Dara Goldberg (@dara_berg_) July 29, 2021 All #Tsunami alerts for the #Alaska coastline have been cancelled. Remember, strong and unusual currents may continue for several hours. If you have damage, please report it to your local officials. Stay safe, get some rest, and we'll keep the watch for you. Good night. https://t.co/wzUBu4ysK3 — NWS Tsunami Alerts (@NWS_NTWC) July 29, 2021 Tonight's M8.2 event occurred close to the rupture area of the 2020 M7.8 earthquake and was the largest U.S. earthquake in 50 years. We'll continue to update as this sequence unfolds, but here is a short piece on our website with what we know so far. https://t.co/PzHaaQ8Zbl pic.twitter.com/vcM8fq9IV7 — Alaska Earthquake Center (@AKearthquake) July 29, 2021 Some Perryville M 8.2 thoughts: One of the arresting things about Chirikof coastal geology is that the island is clearly sinking like a stone today, evident in geodesy and coastal geology. Figure from Nelson et al. 2015 https://t.co/vGKDp0WYuN *BUT* that isn't the entire story pic.twitter.com/LAWLqE1Su3 — Rich Briggs (@rangefront) July 29, 2021 The two closest sites to the M8.2 Alaska earthquake today show some decent surface wave signals. There are several other closer sites that should give us better insight. @UNAVCO pic.twitter.com/lN22i7arEP — Brendan Crowell (@bwcphd) July 29, 2021 8.2 Earthquake is the largest in Alaska since 1965. I was sitting in the upper wheelhouse of my 125' steel schooner ALEUTIAN EXPRESS at Chignik Harbor and the whole boat bounced and vibrated for about a minute. 14' range of gradual Tsunami one foot every 4 minutes both directions pic.twitter.com/IlYox48ejg — John Clutter (@AleutianExpress) July 29, 2021 Interesting look at the tide gauge in Eureka this morning. That perturbation over the last couple of hours is likely associated with the small tsunami waves from Alaska. This is a great reminder that tsunami danger can last well after the specific 'arrival time' #cawx pic.twitter.com/JloflW8aa5 — NWS Eureka (@NWSEureka) July 29, 2021 Additional Information about the M 8.2 earthquake that occurred 50 miles south of the Alaska Peninsula last night. https://t.co/2Jn2DLAV8M #Earthquake #Alaska pic.twitter.com/s1DDPmmaXG — USGS (@USGS) July 29, 2021 Alaska has a M7 earthquake every 2 years on average. So why the big deal about this M8.2? There is a BIG DIFFERENCE between a M7 and a M8. Use this “spaghetti magnitude” scale to visualize the difference. #AlaskaQuake pic.twitter.com/DT3tBzRkxs — Dr. Wendy Bohon (@DrWendyRocks) July 29, 2021 Preliminary Finite Fault Model of the Mw 8.2 Alaska event. @dara_berg_ @geosmx pic.twitter.com/WZNgmu9HWo — Sebastian Riquelme (@accelerogram) July 29, 2021 Clear NE propagation from the M8.2 in Alaska, but look at 102 sec- action to E way updip by the trench. Early aftershock or where rupture finally expired? It's small amplitude, but coherent and seen by 4 very different arrays. I await better analyses.https://t.co/6hFfZ64Elw pic.twitter.com/hacucSnOil — Alex Hutko (@alexanderhutko) July 29, 2021 Good morning all! The tsunami waves are still bouncing around the Aleutian Islands in Alaska (max height measured was ~2 feet). The tsunami turned out not to be very big & all @NWS_NTWC alerts for the US west coast are CANCELLED. 🚨NO alerts for CA, OR, WA. #earthquake pic.twitter.com/uEHSdzzvv9 — Brian Olson (@mrbrianolson) July 29, 2021 Waves from the recent M8.2 #Alaska #earthquake rolling through North America. Different colors correspond to different types of seismic waves. @IRIS_EPO pic.twitter.com/RJBlGh7zFg — UMN Seismology (@UMNseismology) July 29, 2021 Good morning PNW- ICYMI, last night there was a M8.2 earthquake off the Alaska Peninsula. Here, you can see waves from it (bottom) compared to a nearby Alaskan M6.8 (top, similar to our 2001 Nisqually M6.8) at station LEBA near the SW Washington coast. pic.twitter.com/GCCAjbYpII — PNSN (@PNSN1) July 29, 2021 Here I show the cross-section through the Alaska seismicity with projected mechanisms. The largest two events are yesterday's M8.2 quake and last year's M7.8, both subduction interface events. For reference, a cartoon of the shallow subduction zone from https://t.co/Gces1m71C8 pic.twitter.com/bgchTpPT5n — Jascha Polet (@CPPGeophysics) July 29, 2021 You may not have felt it, but a groundwater well in Washington County, Maryland did! An 8.2 magnitude earthquake rocked southern Alaska overnight and the water level in our well sloshed almost a foot. https://t.co/kafsMsaaph. For more real-time well data https://t.co/w56ACDNk4h pic.twitter.com/87fVSz0MLz — @USGS_MD_DE_DC (@USGS_MD_DE_DC) July 29, 2021 15 second sample rate data for AB13 is now available for the M8.2 Alaska earthquake, we see a pretty appreciable SE offset with 10 cm of subsidence. The event started NE of AC12 and ruptured to the NE, so this site is in the middle of it all. @UNAVCO pic.twitter.com/8nTTZstIDX — Brendan Crowell (@bwcphd) July 30, 2021 The largest earthquake to hit the U.S. in the last few decades took place in Alaska yesterday. The Mw 8.2 quake broke the Aleutian megathrust in the Shumagin seismic gap. The rupture did not propagate to the trench, causing only a minor tsunami. Figure by @QQtecGeodesy pic.twitter.com/02ylFet8P6 — Sylvain Barbot (@quakephysics) July 30, 2021 Recent Earthquake Teachable Moment for the M8.2 #AlaskaEarthquakehttps://t.co/2sFE9QDrNb pic.twitter.com/aLtYLIm61i — IRIS Earthquake Sci (@IRIS_EPO) July 30, 2021 14+ hours after the #alaska earthquake and there is still a tsunami bouncing around at the closest tide gauge (small tsunami) pic.twitter.com/3xtjS4hhge — Bill Barnhart (@SeismoSARus) July 29, 2021 There was a bit of confusion and misinformation with the Alaska earthquake last night, so how about us geoscientists put together a thread of seismologists/tsunami experts to follow. I'll start: @CPPGeophysics @SeismoSue @seismo_steve #Earthquake #alaskaearthquake pic.twitter.com/nfbQvfbnQy — Dr Janine Krippner (@janinekrippner) July 29, 2021 As of 12 hours following the M8.2 we've located ~140 aftershocks. The locations and magnitudes are subject to change upon further review, but look to be occurring to the east of 2020 sequence. The map here shows 2020 in gray and the recent aftershocks in red. pic.twitter.com/hQ93k7HVUZ — Alaska Earthquake Center (@AKearthquake) July 29, 2021 Last night's magnitude 8.2 earthquake serves as a powerful reminder of the restlessness of our planet's surface—and it presents an exciting opportunity to peer deeper at our planet’s inner workings. Learn more about Alaska's shakes in my latest @NatGeo https://t.co/gnPANhqWW1 — Dr. Maya Wei-Haas (@WeiPoints) July 29, 2021 Our event page for last night's M8.2 earthquake in Alaska is posted and will be updated as data are made available: https://t.co/XSq1nVyBuU pic.twitter.com/NcUqOKBdGT — UNAVCO (@UNAVCO) July 29, 2021 Slip contours for the July 2020 and 2021 megathrust #earthquakes One begins where the other ends. @bwcphd @dara_berg_ pic.twitter.com/URdqVX2r2R — Sean (@tsuphd) July 29, 2021 (1/3) The "Lame Monster": Today's largest US earthquake in >50 years did not make a large tsunami. Why? These are computer models of the tsunami from the M8.3 earthquake in Alaska#AlaskaQuake #alaskatsunami pic.twitter.com/QlJSWJMaqG — Amir Salaree (@amirsalaree) July 29, 2021 🌊The entire #California coast is a #tsunami hazard area. 🌊The July 27 M8.2 earthquake in #Alaska generated minor tsunami waves that are still being recorded on tide gages here. 🌊Head to ➡️https://t.co/UUkQsqYcAk to learn more about your tsunami risk. pic.twitter.com/pHjrTeOv5o — California Department of Conservation (@CalConservation) July 30, 2021 GPS receivers can be used as seismometers. In blue are the 5 Hz velocities recovered on Kodiak Island with the variometric approach for the M8.2 earthquake yesterday. In red, the collocated accelerometer, S19K, downsampled to 5 Hz. pic.twitter.com/jxJR1v7Fj1 — Brendan Crowell (@bwcphd) July 30, 2021 A notable characteristic of the M8.2 Alaska earthquake is that it was relatively deep and doesn’t appear to have ruptured the shallow plate boundary. Could overpressured sediments on the shallow plate boundary inhibited shallow slip? Check out this seismic image updip of event. pic.twitter.com/HRQEPxrAZk — Donna Shillington (@djshillington) July 30, 2021 We finally have some preliminary coseismic offsets for the M8.2 Alaska earthquake. AB13 has a 43 cm offset to the SE. pic.twitter.com/RSttwW4nBl — Brendan Crowell (@bwcphd) July 30, 2021 While the M8.2 was the largest earthquake in the U.S. in 50 years, Alaska has experienced some significantly sized events during that time. The plot here shows the largest Alaska earthquake magnitude each year since 1964. Since 2000, we're experienced at least a M6.4 annually. pic.twitter.com/Iq9pFanPqi — Alaska Earthquake Center (@AKearthquake) July 30, 2021 Whopper M8.2 earthquake in Alaska moved GPS stations, revealing the broad pattern and extent of deformation. — Bill Hammond (@BillCHammond) July 30, 2021 (1/6) DART Seismology: How the tsunami sensors near Alaska picked up the seismic surface waves from the M8.3 Alaska earthquake! The tails in the records are mixes of surface waves and the tsunami.#alaskaearthquake #alaska_tsunami @NOAAResearch @NWS_PTWC @IRIS_EPO pic.twitter.com/OWI7e47dNq — Amir Salaree (@amirsalaree) July 31, 2021 #EarthquakeReport and #TsunamiReport for M8.2 #Earthquake offshore of #Alaska updated interpretive poster '21 sequence matches '38 sequence for both ~slip patch and ~tsunami size https://t.co/pE3zA9HHFShttps://t.co/mFtEoigFQB — Jason "Jay" R. Patton (@patton_cascadia) August 2, 2021 #Sentinel1 co-seismic interferograms (ascending track) over western Alaska, show ground deformation towards the southern coast, above the main M8.2 #earthquake fault rupture. Aftershock epicenters (yellow) from USGS. pic.twitter.com/RtavuJZGSZ — Sotiris Valkaniotis (@SotisValkan) August 2, 2021 The M 8.2 Chignik earthquake that occurred off the Alaskan Peninsula on July 28 was the largest US earthquake in 50 years. This 2013 simulation from the same region shows how a hypothetical M 9.1 (almost 30x stronger!) earthquake can create a far-reaching tsunami. @USGS_Quakes pic.twitter.com/tLtxWxoal7 — USGS Coastal Change (@USGSCoastChange) July 30, 2021 Updated finite fault model (joint inversion of regional and teleseismic data) is now available: https://t.co/K0kXumE6Pv pic.twitter.com/y7Z9vIF6Lu — Dr. Dara Goldberg (@dara_berg_) August 3, 2021 #EarthquakeReport & #TsunamiReport for M8.2 Perrysville #Earthquake and transpacific #Tsunami updated poster including @USGS_Quakes @dara_berg_ updated slip model also, surface deformation data I prepared a report and will update morehttps://t.co/y1RwyZjKOA pic.twitter.com/lj8qIk7vQl — Jason "Jay" R. Patton (@patton_cascadia) August 4, 2021
This year we look back and remember what happened ten years ago in Japan and across the entire Pacific Basin. Here are all the pages for this earthquake and tsunami: I have several reports from previous years that have reviews of the earthquake and tsunami. I focus mostly on new material I prepared for the following report. Use this map to see the magnitudes of different earthquakes experienced in Japan. The map shows earthquake epicenters for large-magnitude historic events of the past century. It also includes epicenters for all aftershocks and triggered earthquakes for a year after the M 9.1 earthquake, and an outline of the aftershocks, which illustrates the area of the fault that slipped during the M 9.1 earthquake. Earthquake intensity is a measure of how strongly earthquake shaking is felt by people and objects. The further away from the epicenter, the lower the earthquake intensity. Seismologists use computer models to estimate what the intensity will be from an earthquake. The U.S. Geological Survey uses its “Did You Feel It?” (DYFI) system to collect observations about how strongly people in different places felt an earthquake. Use this map to see the level of intensity people felt in different parts of Japan. The map displays the USGS intensity model for the M 9.1 earthquake as transparent colors. The map also shows, as colored circles, the “Did You Feel It?” report results from people who experienced shaking from this earthquake. Tsunami can be caused by a variety of processes, including earthquakes, volcanic eruptions, landslides, and meteorological phenomena. Earthquakes, eruptions, and landslides cause tsunami when these processes displace water in some way. We may typically associate tsunami with subduction zone earthquakes because these earthquakes are the type that generate vertical land motion along the sea floor. Use this map to see tsunami wave data as recorded by tide gages across the entire Pacific Basin. Click on a white triangle and there is a link to open the tide gage data as a graphic. 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. #EarthquakeReport for #OTD 2011 M9.1 Tōhoku-oki #Earthquake #Tsunami #Landslides decade remembrance with some updated maps and web maps report here:https://t.co/n5UI6Co1iv main report w/tectonic details:https://t.co/0jo9XuHxdE pic.twitter.com/MkEAbQkTXe — Jason "Jay" R. Patton (@patton_cascadia) March 11, 2021 #EarthquakeReport #OTDearthquake 2011.03.11 M 9.0 Tohoku-oki earthquake and tsunami. #JapanEarthquake first observed 50+ m slip, fault offset at trench, heatflow from fault-slip friction, triggered outer-rise EQs etc. Many discoveries MORE here:https://t.co/0jo9XuHxdE pic.twitter.com/6gNFZWitDn — Jason "Jay" R. Patton (@patton_cascadia) March 11, 2018
I awakened to be late to attending the GSA meeting today. I had not checked the time. 7am is too early, but i understand the time differences… To the north is a strike-slip plate boundary localized along the North Anatolia fault system. This is a right lateral fault system, where the plates move side by side, relative to each other. See the introductory information links below to learn more about different types of faults.
Seismicity of the Eastern Mediterranean region and surroundings reported by USGS–NEIC during 1973–2007 with magnitudes for M . 3 superimposed on a shaded relief map derived from the GTOPO-30 Global Topography Data taken after USGS. Bathymetry data are derived from GEBCO/97–BODC, provided by GEBCO (1997) and Smith & Sandwell (1997a, b).
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).
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.
Geological map showing the distribution of the Menderes Extensional Metamorphic Complex (MEMC), Oligocene–Miocene volcanic and sedimentary units and volcanic centers in the Aegean Extensional Province (compiled from geological maps of Greece (IGME) and Turkey (MTA), and adapted from Ersoy and Palmer, 2013). Extensional deformation field with rotation (rotational extension) is shown with gray field, and simplified from Brun and Sokoutis (2012), Kissel et al. (2003) and van Hinsbergen and Schmid (2012). İzmir–Balıkesir Transfer zone (İBTZ) give the outer limit for the rotational extension, and also limit of ellipsoidal structure of the MEMC. MEMC developed in two stages: the first one was accommodated during early Miocene by the Simav Detachment Fault (SDF) in the north; and the second one developed during Middle Miocene along the Gediz (Alaşehir) Detachment Fault (GDF) and Küçük Menderes Detachment Fault (KMDF). Extensional detachments were also accommodated by strike-slip movement along the İBTZ (Ersoy et al., 2011) and Uşak–Muğla Transfer Zone (Çemen et al., 2006; Karaoğlu and Helvacı, 2012). Other main core complexes in the Aegean, the Central Rhodope (CRCC), Southern Rhodope (SRCC), Kesebir–Kardamos Dome (KKD) and Cycladic (CCC) Core Complexes are also shown. The area bordered with dashed green line represents the surface trace of the asthenospheric window between the Aegean and Cyprean subducted slabs (Biryol et al., 2011; de Boorder et al., 1998). See text for detail.
Mantle flow pattern at Aegean scale powered by slab rollback in rotation around vertical axis located at Scutary-Pec (Albania). A: Map view of fl ow lines above (red) and below (blue) slab. B: Three-dimensional sketch showing how slab tear may accommodate slab rotation. Mantle fl ow above and below slab in red and blue, respectively. Yellow arrows show crustal stretching.
A: Tectonic map of the Aegean and Anatolian region showing the main active structures
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.
Input GPS velocities of the model. Velocities are in Eurasia fixed reference frame with their respective 95% confidence ellipse. Velocity vectors are color coded relative to the study they have been taken from (see paper for more details). (a) GPS velocities of the entire Nubian plate used to constrain the Nubia–Eurasia relative motion. Nubia–Eurasia rotation pole defined in this and previous studies are shown with their 1s confidence ellipse: circle, Calais et al. [2003]; diamond, Le Pichon and Kreemer [2010]; open square, D’Agostino et al. [2008]; triangle, Argus et al. [2010]; filled square, Reilinger et al. [2006]; red star, present study. Parameters of these rotation poles are summarized in Table 2. (b) Focus on the GPS velocities in the Central and Eastern Mediterranean region.
Input seismic moment tensors of the model. Fault plane solutions are from the Harvard CMT catalog (from 1976 to 2007) and the Regional Centroid Moment Tensor (RCMT) catalog (from 1995 to 2007). Location and hypocenter depth of the events are relocalized according to the Engdahl et al. [1998] catalog.
Outline geological map of western Anatolia showing Neogene and Quaternary basins [simplified from Bingo1 (1989).
Simplified geological map of the northern margin of the Btiytik Menderes Graben in the area between Germencik and Umurlu.
Geological cross-section of the northern margin of the Bt~yt~k Menderes Graben (see Fig. 6b for location) based on fig. llb of Cohen et al. (1995). This cross-section indicates a total of c. 5 km of extension. Assuming a uniform extension rate, the age of the fault zone is (c. 5 km/1 mm a -1) 5 Ma. More details in the paper.
Geology map of the study area (simplified from MTA 1: 500,000 scale geology map) and location of the seismic lines. Active faults are marked onland with bold lines.
Time migrated seismic sections, offshore Teke and Karaburun, showing active normal faults marked with white lines and strike-slip faults with black lines (see Fig. 3A for locations). Vertical exaggeration is ~2. Observed vertical displacement on the seafloor and basement surface by normal fault (marked with bold circle on Line-10) looks the same, thus this normal fault is Quaternary age. On line-18, vertical displacement seen on basement units are greater than displacement on Pliocene–Quaternary deposits due to fault marked with a bold circle thus this normal fault can be interpreted as Later Miocene–Pliocene age.
(A) The correlations between offshore and onshore active fault systems in the study region. N–S, NE–SW and NW–SE oriented lines and dashed-lines show interpreted active strike-slip faults and their possible extensions. These faults are annotated with dNT for those at north and dST for those at south. E–W oriented lines and dashed lines show interpreted active normal faults and their possible continuations, with footwalls indicated by the plus symbol. (B) Simplified active fault map of the study area. The bold lines show the master active faults. (C) Pureshear model can explain the development of active structures in the study area.
Geological map of western Turkey showing the Menderes massif and its subdivision into the AG Alasehir graben, the BMG Büyük Menderes graben, the CMM Central Menderes massif, the KMG Küçük Menderes graben, the NMM Northern Menderes massif and the SMM Southern Menderes massif, modified from Sengör and Bozkurt (2013).
(a) A conceptual model of geothermal circulation in the study area, (b) a deep seismic profile with the N–S direction taken from a 30 km west of study area (Nazilli region) (Çifçi et al., 2011). Roman numerals indicate the different sedimentary sequences.
Simplified geological map of the KMG showing the positions of geological cross-sections.
Series of geological cross-sections showing various sectors of the KMG depicting horst and graben structures overprinted onto the huge synclinal structure (see Fig. 3 for positions of geological cross-sections).
Schematic tentative cross-sections showing the Miocene to Quaternary evolution of the KMG (modified from Erinç [66]). Note the continuing extension since Miocene.
Simplified tectonic map of the Mediterranean region showing the plate boundaries, collisional zones, and directions of extension and tectonic transport. Red lines A through G show the approximate profile lines for the geological traverses depicted in Figure 2. MHSZ—mid-Hungarian shear zone; MP—Moesian platform; RM—Rhodope massif; IAESZ— Izmir-Ankara-Erzincan suture zone; IPS—Intra-Pontide suture zone; ITS—inner Tauride suture zone; NAFZ—north Anatolian fault zone; KB—Kirsehir block; EKP—Erzurum-Kars plateau; TIP—Turkish-Iranian plateau.
Simplified tectonic cross-sections across various segments of the broader Alpine orogenic belt.
Late Mesozoic–Cenozoic geodynamic evolution of the western Anatolian orogenic belt as a result of collisional #EarthquakeReport for #Earthquake #Deprem and #Tsunami in the eastern #AegeanSea offshore of #Turkey poster is now updated with aftershocks from @LastQuake report here:https://t.co/vNuRdWw0Gs pic.twitter.com/SnYXwg2n3T — Jason "Jay" R. Patton (@patton_cascadia) October 31, 2020 #EarthquakeReport #TsunamiReport for M7 offshore of #Turkey small sized tsunami observed across the #AegeanSea https://t.co/i1lZJ0pkb3 analog event in 2017 and more tectonic background herehttps://t.co/jwwXh0SpXl pic.twitter.com/sk1HVbbCKD — Jason "Jay" R. Patton (@patton_cascadia) October 30, 2020 Unfortunately, with the source so close to the coast, any Tsunami Early Warning System (#TEWS) has little room to warn the population in advanced to save lives. Prepareness/education is then the key ingredient. — Jorge Macías Sánchez (@JorgeMACSAN) October 30, 2020 İzmir #deprem Alaçatı #tsunami #deliklikoy pic.twitter.com/Fo74diHpBJ — ulaş tuzak (@ulastuzak) October 30, 2020 M6.9 #earthquake (#deprem) strikes 66 km SW of #İzmir (#Turkey) 21 min ago. Updated map of its effects: pic.twitter.com/Kh3WMz6Hxi — EMSC (@LastQuake) October 30, 2020 Video forwarded by a friend pic.twitter.com/P5g7H7LInn — Tiernan Henry (@tiernanhenry) October 30, 2020 I'd be cautious. A similar EQ occurred offshore Bodrum, SW Turkey, in 2017 (Mw 6.6). Many assumed it ruptured the big mapped normal fault, but careful analysis showed it ruptured a smaller conjugate fault that would've been missing from this database. https://t.co/zEKYatNi1O — Edwin Nissen (@faulty_data) October 30, 2020 #deprem geçmiş olsun İzmir 2020 son hızıyla devam ediyor. pic.twitter.com/cZc3rgWV0e — jojomiyo (@jojomiyo1) October 30, 2020 Fully automatic processing (beta-version) of the expected permament deformation and #InSAR fringes for the M 7.0 #earthquake in #dodecanese (#Greece), 11:51 (UTC). Focal mechanism from USGS, both nodal planes used. With @antandre71 pic.twitter.com/TQiaoDgYf7 — Simone Atzori (@SimoneAtzori73) October 30, 2020 Absolutely terrible scenes coming out of Turkey after the M7.0 earthquake. My thoughts are with all of the people impacted by this event. 💔 https://t.co/gs8Wj8Cj5a — Dr. Wendy Boo – hon 👻 (@DrWendyRocks) October 30, 2020 The October 30 M7 EQ offshore Samos Island, Greece, occurred as the result of normal faulting at a shallow crustal depth within the Eurasia tectonic plate in the E Aegean Sea. This indicates N-S oriented extension that is common in the Aegean Sea. 🍫 https://t.co/r5i9Ni1S1B pic.twitter.com/C6CyLDOlZ1 — USGS Earthquakes (@USGS_Quakes) October 30, 2020 Η #Σάμος άντεξε στο τρομακτικό μέγεθος των 6,7 ρίχτερ ευτυχώς δεν έχουμε θύματα!! #Σεισμός pic.twitter.com/Sd00bTBOd5 — Θεοδόσης Ζερβουδάκης (@tzervoudakis) October 30, 2020 El terremoto de Turquía de hace un rato llevó a un desastre tremendo. Uno que se da por la falta de preparación ante algo así, sobre todo en la parte ingenieril. Tendrá magnitud 7, pero a 10 km de profundidad golpea fuerte a las ciudades cercanas, que estaban mal paradas pic.twitter.com/vomUd3Xauu — Cristian Farías (@cfariasvega) October 30, 2020 30 Ekim 2020 #Seferihisar açıkları (#İzmir)/Sisam (M6.6/6.9) #depremi anaşokundan itibaren 1.0 ile 5.1 arasında değişen toplam 85 deprem oldu. Depremler D-B doğrultulu normal fay boyunca dağılım göstermektedir. pic.twitter.com/65ULhiqEq2 — Dr. Ramazan Demirtaş (@Paleosismolog) October 30, 2020 İzmir'de su seviyesi yükseldi. Tsunami benzeri görüntüler ortaya çıkıyor.#deprem pic.twitter.com/dbxCCgks5C — Politikaloji🇹🇷 (@politikaloji) October 30, 2020 Location of Samos Mw7 #earthquake on Aegean Sea seismo-tectonic sketch. In yellow, grabens / major extension zones. Today's earthquake happened on a major normal fault bounding one of these grabens. Map from Armijo et al. GJI, 1996 pic.twitter.com/qx46D6peTS — Robin Lacassin (@RLacassin) October 30, 2020 Seferihisar'da tsunami… — FORUM ATMOSFER (@forumatmosfer) October 30, 2020 Watch the waves from the M7.0 #earthquake near Turkey roll across seismic stations in Europe. https://t.co/SoZMmJHvCU (THREAD) pic.twitter.com/8YKQHaj2yf — IRIS Earthquake Sci (@IRIS_EPO) October 30, 2020 Map of extension responsible for today's Mw 7.0 earthquake in the Aegean (red star). GPS vectors show motion relative to Anatolia plate. NW Turkey moves N, SW Turkey moves S, so western Turkey stretches N-S. Graph shows how W Turkey opens up like spreading the fingers of a hand pic.twitter.com/JpWklc7YZY — Edwin Nissen (@faulty_data) October 30, 2020 🌊🇬🇷 Vathí es otra localidad al norte de la isla de #Samos que también registró los efectos del tsunami, inundando las zonas más baja de la ciudad. Se observan estragos menores en el registro. Vídeo: @atta_fareid pic.twitter.com/CnZzN6c48l — EarthQuakesTime (@EarthQuakesTime) October 30, 2020 More @NERC_COMET LiCSAR results for yesterday's Aegean earthquake, including filtered/unwrapped interferograms and kmz files for viewing in google earth: https://t.co/TY8ijrUoml — Tim Wright (@timwright_leeds) October 31, 2020 Helpful map showing tectonic setting of today's M7.0 #IzmirEarthquake (yellow dot). The African Plate is subducting under the South Aegean/Anatolian Plate, which is extending as it overrides. The fault that broke today is a "pull-apart" fault (normal fault). #EarthquakeIzmir pic.twitter.com/31Hw4EFWze — Brian OLSON (@mrbrianolson) October 30, 2020 30 Ekim 2020 / İzmir pic.twitter.com/OYzy0n9hF5 — Son Dakika TV (@sondakikativi) October 30, 2020 GPS velocity & direction of surface monitoring stations in the area of today's M7.0 #IzmirEarthquake showing SSW-directed extension towards the African Plate. The stations near the epicenter are moving ~0.9 – 1.3 inches per year (relative to stable African P.) Data via @UNAVCO pic.twitter.com/iVJJO93Gtl — Brian OLSON (@mrbrianolson) October 30, 2020 Today's Mw 7.0 #earthquake near the Greek island of Samos ruptured near the Menderes Graben in Western Turkey, a region with a long history of strike-slip and normal faulting. pic.twitter.com/9FiOreCK2R — Sylvain Barbot (@quakephysics) October 30, 2020 #EarthquakeReport for #Earthquake #Deprem and #Tsunami in the eastern #AegeanSea offshore of #Turkey poster is now updated with aftershocks from @LastQuake report here:https://t.co/vNuRdWw0Gs pic.twitter.com/SnYXwg2n3T — Jason "Jay" R. Patton (@patton_cascadia) October 31, 2020 AGGIORNAMENTO: Terremoto Mw 7.0 a Nord di Samos (Grecia) del 30 ottobre 2020 https://t.co/pnhYLioLb1 — INGVterremoti (@INGVterremoti) October 30, 2020 It is a bit late in the game, but here is a simulation of yesterdays Turkey/Greece tsunami: pic.twitter.com/HrSnsCl2mA — Amir Salaree (@amirsalaree) October 31, 2020 My thoughts are with the bereaved, injured and homeless after yesterday's earthquake in Turkey. The size of the quake is shown on these responses from @raspishake seismometers across the globe. The plot is made using @obspy. pic.twitter.com/wrD1Xhfcx8 — Mark Vanstone (@wmvanstone) October 31, 2020 Map of ground displacements calculated from @CopernicusData Sentinel-1 radar (InSAR) by NASA-JPL ARIA project. Western Samos island moved up (blue tones), small area of coast moved down (red) due to M7.0 earthquake yesterday. Other areas affected by atmosphere. pic.twitter.com/26rFem82YN — Eric Fielding (@EricFielding) October 31, 2020 Jason, also the ~1 days @LastQuake aftershocks distribution seems to be in agreement with the positive stress change related to the @usgs preliminary finite fault model pic.twitter.com/7FNr52Aat2 — Jugurtha Kariche (@JkaricheKariche) October 31, 2020 The red curve below represents the intensity (i.e. shaking and damage level) vs epicentral distance for yesterday M7 #Izmir #Samos #earthquake #deprem. The blue dots are individual felt reports shared by eyewitnesses via LastQuake app. — EMSC (@LastQuake) October 31, 2020 Preliminary teleseismic finite fault model of the 30 Oct Mw 7 Greece #earthquake for both planes. Method= Ji et al. (2002). Here rupture started from the KOERI hypocenter (H=10 km). Rupture moved bilaterally; most of the high slip and its peak located up-dip in the shallow depth. pic.twitter.com/7E4jpwJzvu — Dimas Sianipar (@SianiparDimas) November 1, 2020 Regional tectonics of the area where the M7.0 Samos #earthquake occurred pic.twitter.com/XaWmKMsrlA — IRIS Earthquake Sci (@IRIS_EPO) November 2, 2020 A bit of lunchtime #dataviz. — Stephen Hicks 🇪🇺 (@seismo_steve) November 2, 2020 Damage Proxy Map from ARIA shows surface changes that may be due to damage measured with radar images. Maps on NASA Disasters Portal: https://t.co/Q4JA2ezU8R — Advanced Rapid Imaging & Analysis (ARIA) (@aria_hazards) November 2, 2020 The "GEER-069: 2020 #Samos Island (Aegean Sea) #earthquake Report" by @HAEE_ETAM, @DepremVakfi, #TDMD, @EERI_tweets and #GEER has been published and is available online (https://t.co/7pb7V8kSMx) ! pic.twitter.com/zpNehqIrTg — EQUIDAS (@equidas) January 3, 2021
Well, it has been a busy couple of weeks. https://earthquake.usgs.gov/earthquakes/eventpage/us6000ah9t/executive The west coast coastline of southern Mexico, Central America, and South America is formed by a convergent plate boundary where oceanic tectonic plates dive eastwards beneath the continents. The fault formed at this plate boundary is called a subduction zone and the dynamics of subduction zones form deep sea trenches. I spend a few paragraphs discussing the different faults that form at different plate boundaries here. Offshore of southern Mexico the Middle America trench shows us the location of the subduction zone megathrust fault. This fault system has a long history of damaging earthquakes, including some events that affect areas hundreds of kilometers from the source earthquake (e.g. the 1985 magnitude M 8 Mexico City earthquake). In the past few years, evidences this megathrust is active continue to present themselves. There is a list of some earthquake reports at the bottom of this page. The earthquake generated seismic waves that travelled around the world, including some that caused strong shaking in Mexico City. Mexico City was built where the Aztec Civilization had once constructed a great city. This city was built next to a lake where the Aztec constructed floating gardens. Eventually, these gardens filled the lake and the lake filled with sediment (I am simplifying what happened over a long time). So, Mexico City is built in a sedimentary basin. Sedimentary basins can amplify shaking from seismic waves. These basins can also focus seismic waves and these waves can resonate within the basin, causing further amplification. This is why there was so much damage in Mexico City from the 1985 subduction zone earthquake. The same thing happened a couple years ago for a recent earthquake there. Well, when subduction zone earthquakes happen, the crust around the fault can flex like the elastic on one’s waist band. As the crust moves, if that crust is beneath the water, this crust motion moves the water causing a tsunami. There are a number of organizations that monitor the Earth for earthquakes that may cause tsunami. These organizations alert officials in regions where these tsunami may inundate so that residents and visitors to the coast can take action (e.g. head to high ground). These programs save lives. This M 7.4 earthquake generated a tsunami that was recorded along the coastline, but not at all tide gage stations. The Salina Cruz station has a great record of this tsunami and is located >80 km from the epicenter. The Acapulco station also recorded a tsunami, but those data were not uploaded to the IOC website (they are working this out now). It appeared that the Acapulco data were being streamed in real time, but I noticed that they were the same data as posted for the Salina Cruz station. Here I plot the water surface elevations observed at the Salina Cruz tide gage. I mark the earthquake event time and the tsunami arrival time, then calculate the tsunami travel time. The Wave Height of the tsunami is the vertical distance measured between the peak and the trough. These data show a Maximum Wave Height of 1.4 meters. The strong ground shaking from an earthquake can also cause landslides and liquefaction. I discuss these further down in this report and include maps in the poster.
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.
Kinematic model (mantle reference frame) of the subducting Cocos slab along the MAT in the vicinity of Cocos–Caribbe–North America triple junction since Early Miocene. The evolution of Caribbean–North America tectonic contact is based on the model of Witt et al. (2012). The blue strips represent markers on the Cocos plate. Note how trench roll forward is associated with steep slab in Central America, whereas trench roll back is associated with flat slab in Mexico.
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.
Present setting of Central America showing plates, Cocos crust produced at East Pacifi c Rise (EPR), and Cocos-Nazca spreading center (CNS), triple-junction trace (heavy dotted line), volcanoes (open triangles), Middle America Trench (MAT), and rates of relative plate motion (DeMets et al., 2000; DeMets, 2001). East Pacifi c Rise half spreading rates from Wilson (1996) and Barckhausen et al. (2001). Lines 1, 2, and 3 are locations of topographic and tomographic profi les in Figure 6.
(A) Tomographic slices of the P-wave velocity of the mantle at depths of 100, 300, and 500 km beneath Central America. (B) Upper panels show cross sections of topography and bathymetry. Lower panels: tomographic profi les showing Cocos slab detached below northern Central America, upper Cocos slab continuous with subducted plate at Middle America Trench (MAT), and slab gap between 200 and 500 km. Shading indicates anomalies in seismic wave speed as a ±0.8% deviation from average mantle velocities. Darker shading indicates colder, subducted slab material of Cocos plate. Circles are earthquake hypocenters. Grid sizes on profi les correspond to quantity of ray-path data within that cell of model; smaller boxes indicate regions of increased data density. CT—Cayman trough; SL—sea level (modifi ed from Rogers et al., 2002).
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.
Tectonic framework of the Cocos plate convergent margin. Top- General view. Yellow arrows indicate direction and speed (in cm/yr) of plate convergence, calculated from the Euler poles given by DeMets et al. (2010) for CocoeNoam (first three arrows, from left to right), and CocoeCarb (last four arrows). Length of arrow is proportional to speed. Red arrow shows location of the 96 longitude. Box indicates location of lower panel. Bottom- Location of features and places mentioned in text. Triangles indicate volcanoes of the Central American Volcanic Arc (CAVA) with known Holocene eruption (Siebert and Simkin, 2002).
Seismicity along the convergent margin. Top: Map view. Blue circles are shallow (z < 60 km) hypocenters; orange, intermediate-depth (60 < z < 100 km); yellow, deep (z > 100 km). Next three panels: Earthquakes as a function of longitude and magnitude for shallow (blue dots), intermediate (orange), and deep (yellow) hypocenters. Numbers indicate number of events on each convergent margin, with average magnitude in parenthesis. Gray line in this and subsequent figures mark the 96 deg longitude.
Location of hypocentral cross-sections. Hypocentral depths are keyed as in previous figures.
Hypocentral cross-sections. Depths are color-coded as in previous figures. Dashed lines indicate the 60-km and 100-km depths. Tick marks are at 100-km intervals, as shown on the sections. There is no vertical exaggeration and Earth’s curvature is taken into account. Number of sections refers to location on Fig. 3.
Earthquake fault-plane solutions from CMT data. a. Shallow (z < 60 km), thrust-faulting mechanisms. b. Intermediate-depth (60 < z < 100 km) thrust-faulting events. c. Deep (z > 100 km), thrust-faulting earthquakes. d. to f. Normal-faulting events, in same layout as for thrust-faulting events.
FOS = Resisting Force / Driving Force #EarthquakeReport in Mexico for M 7.4 #Earthquake #Terremoto be safe everyonehttps://t.co/jTfZEjQ0H0 more on tectonic background herehttps://t.co/5jgHU1xxbx pic.twitter.com/H1moPjQtqR — Jason "Jay" R. Patton (@patton_cascadia) June 23, 2020 #EarthquakeReport for the M 7.4 #Terremoto #Earthquake #Tsunami in #Oaxaca #Mexico shaking felt in #MexicoCity poster previously posted is updated and explained in report here:https://t.co/jCM8vu0ccX pic.twitter.com/C7OD8UobyL — Jason "Jay" R. Patton (@patton_cascadia) June 25, 2020 Watch the waves from the M7.4 Mexico earthquake roll across seismic stations in North America! (THREAD) pic.twitter.com/7dpPr1Ueuy — IRIS Earthquake Sci (@IRIS_EPO) June 23, 2020 Tide gauge at Salina Cruz, Mexico#SantaMaríaZapotitlán for M7.4 earthquake. pic.twitter.com/RNVYbzxseM — Nick Graehl (@nickgraehl) June 23, 2020 #Terremoto en México: en estas impactantes imágenes, tomadas en Bosques de las Lomas (#CDMX), podemos observar como ambos lados de una grieta se mueven ligeramente durante el seísmo.pic.twitter.com/u50mCx1XFS — eSPAINews (@eSPAINews) June 23, 2020 Heres my first cut at estimating offsets for the event today in Mexico. I will add more sites as they become available. The mechanism is USGS W-phase. pic.twitter.com/PomjZF0JKL — Brendan Crowell (@bwcphd) June 23, 2020 #Earthquake_alert – Source: @Bersa76#CDMX Así se sintió el sismo en el nivel 56 de la Torre Mitikah en la alcaldía Benito Juárez, se trata de un inmueble de 267.3m de altura. pic.twitter.com/J6cpAZfPIU#Mexico #earthquake #alert #warning #mitigation #tsunami — Desianto F. Wibisono (@TDesiantoFW) June 23, 2020 VIDEO: A building swaying in Mexico City’s La Condesa neighborhood, after today’s 7.4 quake in southern Mexico, according to @TVVnoticias pic.twitter.com/BKJrilJZ8s — Manuel Bojorquez (@BojorquezCBS) June 23, 2020 "Nearly" automatic forward model based on the USGS focal mechanism for the M 7.4 #Mexico #earthquake (June 22, 15:29 UTC). And expected InSAR fringe pattern from C-band ascending orbit. Waiting, as usual, for real InSAR data. — Simone Atzori (@SimoneAtzori73) June 23, 2020 #DÚltimaHora #D7 Cerrada la Carretera Oaxaca-Istmo por Derrumbe en las Cercanías de la Comunidad del Camarón, evite Viajar más información en un momento. pic.twitter.com/B3G5b17YZv — Domingo 7 (@domingo7th) June 23, 2020 A 7.4 magnitude #earthquake has hit the southern coastline of #Mexico. #Sismo #Temblor #Oaxaca #CDMX #AlertaSismica pic.twitter.com/doiICbJHuy — DailyNewsf (@DailyNe25683877) June 23, 2020 #sismo2020 #sismo | En la Roma Norte, el movimiento causó daños en la azotea de una edificio, del cual comenzaron a caer chorros de agua pic.twitter.com/LqA4fVKhBy — RedTvo Television (@redtvo) June 23, 2020 El #sismo magnitud 7.1 con epicentro en Crucecita Huatulco, #Oaxaca. Ocasionó daños en el Centro Histórico de la Capital. pic.twitter.com/iD70elgxP1 — Diario El Fortín (@diarioelfortin) June 23, 2020 En la zona platanera de Teapa, Tabasco, así se percibió el sismo de 7.5 #CDMX #oaxaca pic.twitter.com/sgpd4lKvOs — Desde Peninsula (@DesdePeninsula) June 23, 2020 Playa Riscalillo, mar se aleja unos cien metros. Bahía principal de Huatulco, mar se aleja unos 30-40 metros#ReporteCiudadano#TenemosSismo #Oaxaca #Huatulco pic.twitter.com/rZNa5AWDFr — Periodistas Oaxaca (@PeriodistasOax) June 23, 2020 OXUM roughly 75 km away to the west had pretty sizable vertical motions. pic.twitter.com/YIltT3uBE4 — Brendan Crowell (@bwcphd) June 23, 2020 Así se sintió el sismo de 7.5 está mañana en Xochimilco pic.twitter.com/yK0CCKwGNt — Salvador García Soto (@SGarciaSoto) June 23, 2020 Earthquake in Mexico City- still occurring – not sure where epicenter is nor if there is any real damage pic.twitter.com/KDAou9YhPG — (@Andalalucha) June 23, 2020 First rough model of the tsunami from today's M7.5 earthquake in Mexico using the USGS finite fault as input. Clear edgewaves and shelf resonance in the Tehuantepec gulf. https://t.co/2FAV5m81ZX — Diego Melgar (@geosmx) June 23, 2020 Today's Oaxaca tsunami in the Pacific. So far, only on 43413… pic.twitter.com/hDqG2ip3jI — Amir Salaree (@amirsalaree) June 23, 2020 El 23 de junio del 2020, un terremoto M7.4 cerca de Oaxaca, México, ocurrió como resultado de una falla inversa en o cerca del límite de la placa que está entre las placas de Cocos y América del Norte. (Enlaces y detalles: https://t.co/qvcse5eYQe) pic.twitter.com/53IxlOr0VG — USGS (@USGS) June 23, 2020 A section from today's M7.4 earthquake near Santa María Zapotitlán at 2020-06-23 15:29:05 UTC recorded on the worldwide @raspishake network and processed with a wider frequency range than I normally use. See: https://t.co/44McZsCCpE. Uses @obspy & @matplotlib software. pic.twitter.com/kItaJfsJ4W — Mark Vanstone (@wmvanstone) June 23, 2020 GSN and other global surface & body wave record sections for the M7.4 Mexico earthquake https://t.co/FvU7Jlak3R pic.twitter.com/YdvRb3iInc — IRIS Earthquake Sci (@IRIS_EPO) June 23, 2020 How big was that magnitude 7.4 earthquake? According to my calculations (see below), it's as if about 4 trillion college students jumped about 1 ft. And, that's about 500 times the population of planet Earth! (Peer review of my calculations is welcome…) pic.twitter.com/TlrmXhQSLj — Alan Kafka (@Weston_Quakes) June 24, 2020 #Mexico M7.4 #earthquake — Vincenzo De Novellis (@VDN75) June 24, 2020 #ERCC #DailyMap: 2020-06-24 ⦙ Mexico | 7.4M Earthquake of 23 June ▸https://t.co/mdRq0Me6LL pic.twitter.com/z7vgXVrfRG — Copernicus EMS (@CopernicusEMS) June 24, 2020 I find it mightily impressive that the low-cost geophone sensors inside @raspishake seismometers were able to capture the long-period surface wave signals, as well as higher-freq body waves, from yesterday's M7.4 Mexico earthquake. — Stephen Hicks (@seismo_steve) June 24, 2020
Earthquake Report: M 7.6 Earthquake in Mexico
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.
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.
Tsunami Report: Hunga Tonga-Hunga Ha’apai Volcanic Eruption & Tsunami
There was a large volcanic eruption in the Tonga region. This eruption was observable from satellites and has generated a modest but observable tsunami from Australia to the United States.
This event is still unfolding and it will take months until we have a deeper understanding of the causes for the tsunami. We know it is related to the explosive volcanic eruption from Hunga Tonga-Hunga Ha’apai, about 55 kms (35 miles) northwest of the largest island of the Kingdom of Tonga, Tongatapu.
I will continue to fill in details. I am currently busy trying to manage our tsunami event response and am learning lots in the process. However, this delays my time available here.
Summary of effects in California, and the state's response – Visit the DOC’s CGS @CalConservation @CAGeoSurvey website to learn more about the impact to #California and to stay updated over time: https://t.co/Fp42JRXYmz pic.twitter.com/ldJ7QTKeI2
Below there are many tweets etc. and one may feel like they are scrolling forever. These tweets are loosely organized into several sections.
Background Material
Tsunami Notifications
"If a tsunami does impact California, it is unlikely it will be a large tsunami but possibly in the Advisory range (0.3m to 1m) and it could arrive at about 0700AM Pacific time according to the NTWC." https://t.co/ioUmU0Yrd3 https://t.co/0b8aE12CV5
However, based on the latest information, there is NO TSUNAMI THREAT for American Samoa at this time.
Because this volcano remains active, please stay tuned for further updates.
Tsunami | Volcano Education
What boaters should know brochure for CA:https://t.co/OWXiUYuAhg
> Strong and unpredictable currents, especially where there are narrow entrances, narrow openings, and other narrow parts of harbor.
3. Much tsunami damage happens in ports because of the currents. Moving water has huge momentum.
[2/2]
A few sample sites for information:#EMBC: https://t.co/nbn6eGEhye
CRD #yyj: https://t.co/6yVbOlZeRD
Alberni: https://t.co/VWxLMdPtF1
Tofino: https://t.co/lvoZGmhTK8
Most important – check with, and follow the advice of your local emergency managers! pic.twitter.com/LURr5aFH3S
Tsunami Observations
USA (CA)
The first surge may not be the largest. In other locations today, the largest surge came much later than the first arrival time. In Monterey, CA it may have 2.5 feet above high-tide conditions, similar to a King Tide event. pic.twitter.com/3h7cpXiPZr
A Tsunami is occurring. Remember- the first wave may not be that largest. Move away from the shore and head to high ground. https://t.co/npoUHxEZLS pic.twitter.com/HmXl5cyIkr
(L) Sat. morning Jan 15
(R) Thurs. afternoon Jan 20 pic.twitter.com/XAAnzYK8GH
From here a resort on Tongatapu.
Don’t do what the videographer here did. This was unsafe and they are incredibly lucky.
Some videos on Youtube: Santa Cruz
Crescent City
Oregon
21 cm (.7 ft) at Newport, OR
6 cm (.2 ft) at Astoria, OR
15 cm (.5 ft) at Westport, WA
34 cm (1.1 ft) at La Push, WAPacific
El oleaje arrasó con al menos dos muelles uno que aparentemente sería de acceso público y otro privado, se mantiene alerta de tsunami en la zona.pic.twitter.com/ChYMvIM2wr
Port San Luis, CA: 4.3 ft
King Cove, AK: 3.3 ft
Crescent City, CA: 3.7 ft
Point Reyes, CA: 2.9 ft pic.twitter.com/HeZJldZlxZ
Photos: Haloti Ulufonua, FB pic.twitter.com/QndVbTYtgo
Hopefully aerial views by New Zealand Defence Force suggest #tsunami height of only few meters and limited inundation distance.
Here Nomuka island 70km NE of Hunga Tonga volcano. Google earth 2016 image follows pic.twitter.com/bUgwtsJ7f8
↙️18 Dec. 2021 ↘️17 Jan. pic.twitter.com/rtrWOXgpC4
Tsunami Modeling
Volcano Eruption | Atmospheric Observations
For more information on volcanic ash go here: https://t.co/AKigF7Zcwy
The health hazards here: https://t.co/30JBdoEpgMhttps://t.co/KSH2fr1tNR
今日15日(土)の20時から21時過ぎにかけて、日本全国で一時的な気圧変化が見られました。火山島フンガトンガ・フンガハアパイが午後に噴火した時の衝撃波が到達した可能性があります。https://t.co/p4ofQT1pC8 pic.twitter.com/yEVBFzVxCH
The spectrum shows signal at <0.06 Hz (>17 sec) & at 0.1 to 0.2 Hz (5 to 10 sec), which fits for ocean & continental Rayleigh waves.@jpulli @stevenjgibbons @KaseyAderhold pic.twitter.com/hJZJvO59PM
More important is how the people of Tonga are and is this over? We do not know. https://t.co/YiJ4vahkPu
Here is the pressure wave from the #HungaTongaHungaHaapai eruption in the infrasound section. The wave taking the path the other way around Earth is also clearly visible a few hours later.
Dashes: speed of sound#Tonga pic.twitter.com/ukkm1AXZCx
❄️cooling of the upper #troposphere by some degrees and 🔥warming the lower #stratosphere
the #tropopause pushed up by 600m in a 10°x15° area and by more then 1km locally pic.twitter.com/l1oHod0Apz
Fascinating | Sad Observations
Tsunami Webcam Network
Earthquake Report Lite: M 7.0 near Acapulco, Mexico
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.
Last afternoon (my time) there was an M 7.0 earthquake near Acapulco, Mexico. This event generated a tsunami, landslides, building damage, casualties (one fatality as I write this), and many emotions.
https://earthquake.usgs.gov/earthquakes/eventpage/us7000f93v/executive
I present my interpretive poster and a few figures. Read more about the tectonics of this region here, in a report for an M 7.4 earthquake in 2020.Below is my interpretive poster for this earthquake
I include some inset figures.
Tide Gage Data – Acapulco
Earthquake Intensity
Mexico | Central America
General Overview
Earthquake Reports
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report Lite: South Sandwich Islands
https://earthquake.usgs.gov/earthquakes/eventpage/us6000f53e/executive
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.
Seismicity Cross Sections
Tide Gage Data
Scotia | Sandwich (MMMMM)
General Overview
Earthquake Reports
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
EarthquakeReport M 7.1 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.
https://earthquake.usgs.gov/earthquakes/eventpage/us6000f48v/executiveBelow is my interpretive poster for this earthquake
I include some inset figures.
Philippines | Western Pacific
Earthquake Reports
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report: M 8.2 near Perryville, Alaska
https://earthquake.usgs.gov/earthquakes/eventpage/us6000f02w/executive
Rick Wilson runs the tsunami program at the California Geological Survey (CGS) and works with the California Governor’s Office of Emergency Services (Cal OES) to use official forecasts of tsunami size from the National Tsunami Warning Center (NTWC) to alert coastal emergency managers about the level of potential evacuation that they may want to act upon.
More about this process can be found here. Take a look at the CGS Special Report 236 to learn about the Tsunami Playbooks and the “FASTER” approach for tsunami evacuation guidance. Evacuation is something that is done at the local level, so CGS and Cal OES can only provide recommendations.
Needless to say, we were both at the ready to respond. Rick has hourly phone calls with the NTWC and follows up with phone calls and emails to specific interested parties (e.g. the emergency managers). We each went into tsunami response mode. I manage the Tsunami Event Response Team, which may be activated to collect observations of tsunami inundation or ocean currents.
I started looking at tide gage and DART Buoy data to see how large the tsunami was in the epicentral region. The M 8.2 was in the region of the 1938 M 8.2 earthquake which generated a transoceanic tsunami. I also looked into the literature about the 1938 tsunami, to see what size that tsunami was. The 1938 tsunami had a decimeter scale wave height (peak to trough) for gages in Alaska and in California (Johnson and Satake, 1994). Jeff Freymueller et al. (2021) had also recently worked on the 1938 earthquake source area and tsunami modeling as well.
The nearest tide gage for this 2021 event is at Sand Point, but the nearest gage in 1938 was in Unalaska. So, in order to get a modest comparison between 1938 and 2021, I felt a need to wait for the Unalaska data to trickle in. This may give us some idea whether the 1938 tsunami recorded in Crescent City and San Francisco might be a decent analogue. Of course, we need to get the official forecast from the NTWC prior to sending out any information. But, that process can take hours (over 3 hours in this case). So, we need to get our minds wrangled around the possibilities in the absence of more information.
Earthquake and Tectonic Background:
The plate boundary in the north Pacific is a convergent (pushing together) plate boundary where the Pacific plate on the south ‘subducts’ northwards beneath the North America plate on the north. The Alaska-Aleutian subduction zone forms a deep sea trench which can be seen in maps of the region. The subduction zone fault dips into the Earth, getting deeper to the north.
Between earthquakes (the interseismic period), the megathrust fault is seismogenically coupled (i.e. ‘locked’) just like velcro has the ability to hold together one’s wallet. The plates are always moving towards each other. Because the fault is locked, the crust surrounding the fault bends elastically to accommodate this convergent motion.
As the crust bends and flexes, it stores energy (i.e. tectonic strain). The part of the fault closest to the seafloor (the southernmost part of this subduction zone fault) gets pulled downwards, while the part of the crust further to the north flexes upwards.
The materials along the earthquake fault have properties that resist motion (like the velcro). But, as the plates converge and increase the amount of energy stored, the forces on the fault may exceed the strength of the fault. At this time, the fault slips, causing an earthquake.
The part of the fault that was being pulled downwards gets pushed upwards during the earthquake (the coseismic period), while the crust that was being flexed upwards between earthquakes thus subsides downwards during the earthquake.
The Alaska-Aleutian subduction zone has a history of subduction zone earthquakes and tsunami, plus there exists a prehistory of earthquakes and tsunami in some parts of this plate boundary. Geologists are often asked to determine the potential hazard of future earthquakes and tsunami and their answers are based on what we know from the past (using both historic and prehistoric data).
The 2021 M 8.2 earthquake happened in the same location as a 1938 M 8.2 earthquake, just to the east of a sequence of earthquakes from last year (22 July and 19 October 2020).
Tsunami:
When the earthquake fault slips, and the upper plate deforms, the vertical motion of the plate can elevate (or lower) the overlying ocean water. After the water changes position, it seeks to return to sea-level (an equipotential surface). If elevated, the water drops downwards and then oscillates up and down. This is the process that generates waves that radiate from the area with seafloor deformed by the earthquake.
Things that make a tsunami larger are [generally]:
First of all, based on the earthquake slip models (estimates of how the earthquake slipped, in meters, and how that slip varied along the fault) suggest that a majority of the largest slip happened beneath the continental shelf. The water depth on the shelf is similar to many shelfs worldwide, shallower than about 200 meters. How does this affect the size of the tsunami?
Well, I guess that is the main point, the ground deformation that generated the tsunami was beneath shallow water.
These slip models are based on a variety of data and most of the data are seismic data. Some tsunami are generated by slow slip (not generating seismic waves) on the shallow part of the fault. These are called tsunami earthquakes.
Because tsunami earthquakes may be generated by slip in this way, slip models using seismic data cannot resolve the location of the slip on the fault that created these tsunami. However, the tsunami from this 2021 M 8.2 earthquake were small. Therefore the updip part of the fault probably did not contribute significantly to the tsunamigenic ground deformation.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 present 3 posters, each with slightly different information.
Tectonic Overview
Youtube Source IRIS
mp4 file for downloading.
Credits:
Here is a cross section showing the differences of vertical deformation between the coseismic (during the earthquake) and interseismic (between earthquakes).
This figure, from Atwater et al. (2005) shows the earthquake deformation cycle and includes the aspect that the uplift deformation of the seafloor can cause a tsunami.
Here is a figure recently published in the 5th International Conference of IGCP 588 by the Division of Geological and Geophysical Surveys, Dept. of Natural Resources, State of Alaska (State of Alaska, 2015). This is derived from a figure published originally by Plafker (1969). There is a cross section included that shows how the slip was distributed along upper plate faults (e.g. the Patton Bay and Middleton Island faults).
Here is a graphic showing the sediment-stratigraphic evidence of earthquakes in Cascadia, but the analogy works for Alaska also. Atwater et al., 2005. There are 3 panels on the left, showing times of (1) prior to earthquake, (2) several years following the earthquake, and (3) centuries after the earthquake. Before the earthquake, the ground is sufficiently above sea level that trees can grow without fear of being inundated with salt water. During the earthquake, the ground subsides (lowers) so that the area is now inundated during high tides. The salt water kills the trees and other plants. Tidal sediment (like mud) starts to be deposited above the pre-earthquake ground surface. This sediment has organisms within it that reflect the tidal environment. Eventually, the sediment builds up and the crust deforms interseismically until the ground surface is again above sea level. Now plants that can survive in this environment start growing again. There are stumps and tree snags that were rooted in the pre-earthquake soil that can be used to estimate the age of the earthquake using radiocarbon age determinations. The tree snags form “ghost forests.
This is a photo that I took along the Seward HWY 1, that runs east of Anchorage along the Turnagain Arm. I attended the 2014 Seismological Society of America Meeting that was located in Anchorage to commemorate the anniversary of the Good Friday Earthquake. This is a ghost forest of trees that perished as a result of coseismic subsidence during the earthquake. Copyright Jason R. Patton (2014). This region subsided coseismically during the 1964 earthquake. Here are some photos from the paleoseismology field trip. (Please contact me for a higher resolution version of this image: quakejay at gmail.com)
This is another video about the 1964 Good Friday Earthquake and how we learned about what happened.
Tsunami Data
Each plot includes three datasets:
Note the all tsunami wave height plots are the same vertical scale, except for Sand Point.
I measured the largest wave heights for each site, displayed in yellow.
Alaska
Here are the data from the DART buoy nearest the M 8.2. People often mistake these data for tsunami data, but this is generated by seismic waves.
One way to test one’s hypothesis about whether these buoy data are seismic waves or tsunami waves, one simply need to take a look at the time that the wave begins to be recorded by the DART buoy.
Seismic waves travel through water at about 1.5 kms per second. While tsunami wave velocity (based on the shallow water wave equation) for depths ranging from 200-4000 meters is between ~0.02 to 0.2 kms per second, much slower than seismic waves.
Surface Deformation
North, East, and Up are positive (blue) while South, West, and Down are negative (red).
Note the upper panel and how the Pacific plate is moving to the north and the North America is moving south. Does this make sense?
The middle panel is interesting too, but skip to the lower panel, vertical. The accretionary prism (forming the continental slope), directly above the aftershocks and mainshock, rises up during the earthquake. The upper North America plate landward of the slip patch subsides. Does this make sense?
Earlier in this report we took a look at the geologic evidence for megathrust subduction zone earthquakes, evidence that records this “coseismic” subsidence.
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.
Some Relevant Discussion and Figures
Fig. 1). Dotted horizontal lines show our correlation of evidence for some younger earthquakes and tsunamis. Times of great earthquakes inferred from episodes of village abandonment determined from archaeological stratigraphy in the eastern Alaska-Aleutian megathrust region are also shown (Hutchinson and Crowell, 2007).
Alaska | Kamchatka | Kurile
General Overview
Earthquake Reports
Social Media
BREAKING: Tsunami sirens sound in Kodiak, Alaska after a major magnitude 8.2 earthquake struck off the coast; risk being evaluated for the Pacific pic.twitter.com/amxpLGX70s
tectonic background:https://t.co/L4RHgNdex7 pic.twitter.com/uQ2ur85EaC
My initial guess that today's event may have been similar to the 1938 M8.2 earthquake still looks like it has some merit.
Follow https://t.co/A1MNRg1WKF for updates on tsunami warnings. pic.twitter.com/g4qME2w0SI
tsunami prehistory and history for region doi:10.1130/GES01108.1https://t.co/mFtEoigFQB
more background here https://t.co/L4RHgNdex7 pic.twitter.com/HXpQUVSWFE
B/c most of elastic energy was released deeper in the Earth.
Stations near Denali NP ~900 km moved a few mm… See https://t.co/4zpOW4m1pJ for more info and data. pic.twitter.com/j1GSIazVfJ
tectonic background here:https://t.co/L4RHgNdex7 pic.twitter.com/iTMmm5u2LQ
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report: Tōhoku-oki Earthquake Ten Years Later
There are numerous web experiences focused on this type of reflection. Here is a short list, some of which I have been involved in.
Updated Interpretive Poster
I include some inset figures.
Seismicity
Web Map
Earthquake Intensity
Web Map
Tsunami
We think that the earthquake slipped at least 50 meters (165 feet) during several minutes. This is the largest coseismic measurement of any subduction zone earthquake (so far).
When the fault slipped, it caused the seafloor to deform and move. This motion also displaced the overlying water column.
As the water column is elevated, it gains potential energy. As this uplifted water expends this energy by oscillating up and down, it radiates energy in the form of tsunami waves.
Tsunami were observed across the entire Pacific Basin, causing extensive damage and casualties in Japan, but also in other places too. There was about $100 million damage to coastal infrastructure in California alone.
This is an animated model of the Great East Japan tsunami of ten years ago. The warmer the colors, the larger the wave. The first surges reached the closest Japan coasts in about 25 minutes. The first surges reached Crescent City in 9.5 hours. (modified text from Dr. Lori Dengler)
This is the same map used as an overlay in the web map below.
Here is the tide gage record from Crescent City, California, USA.
Time is represented by the horizontal axis and elevation is represented on the vertical axis. The darker blue line in this image represents NOAA’s tidal forecast. The data recorded by the tide gage are represented by the light blue colored lines. Wave height is the distance measured between the wave crest and trough. Wave amplitude is the level of water above sea level.
Some of these data came from the IOC sea level monitoring website.
Web Map
There is an overlay of color that represents the size of the tsunami as it travelled across the ocean. Learn more about these data here.
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.
Use this map to see the magnitudes of different earthquakes experienced in Japan. The map shows earthquake epicenters for large-magnitude historic events of the past century. It also includes epicenters for all aftershocks and triggered earthquakes for a year after the M 9.1 earthquake, and an outline of the aftershocks, which illustrates the area of the fault that slipped during the M9.1 earthquake.
Web Map
Japan | Izu-Bonin | Mariana
General Overview
Earthquake Reports
Social Media
check out the tide gage plots, about 50 of them
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report: Turkey!
As i was logging into Zoom, my coworker emailed our Tsunami Unit group about a M7 in the eastern Mediterranean. So, I shifted gears a bit. But i had my poster to present, so i had to stay somewhat focused on that.
https://earthquake.usgs.gov/earthquakes/eventpage/us7000c7y0/executive
Today, in the wee hours (my time in California), there was a M 7.0 earthquake offshore of western Turkey in the Icarian Sea. The earthquake mechanism (i.e. focal mechanism or moment tensor) was for an extensional type of an earthquake, slip along a normal fault.
I immediately thought about some quakes/deprems that happened there several years ago. This area is an interesting and complicated part of the world, tectonically.
To the south is a convergent plate boundary (plates are moving towards each other) related to (1) the Alpide Belt, a convergent plate boundary formed in the Cenozoic that extends from Australia to Morocco. On the southern side of Greece and western Turkey, there are subduction zones where the Africa plate dives northward beneath the Eurasia and Anatolia plates.
The region of today’s earthquake is in a zone of north-south oriented extension. This extension appears to be in part due to gravitational collapse of uplifted metamorphic core complexes.
There are several “massifs” that were emplaced in the past, lifted up, creating gravitational potential. The normal faults may have formed as the upper crust extended. It is complicated here, so i am probably missing some details. But, with the references i provide below, y’all can read more on your own. Feel free to contact me if i wrote something incorrect. I love my peer reviewers (you).
So, this N-S extension creates east-west oriented valleys/basins with E-W striking (trending) faults. There are south dipping faults on the north sides and north dipping faults on the south side of these valleys.
These structures are called rifts. A famous rift is the East Africa Rift.
There are two main rifts in western Turkey, the Büyük Menderes Graben and the Küçük Menderes Graben Systems. If we project these rifts westward, we can see another rift, the rift that forms the Gulf of Corinth in Greece, the Gulf of Corinth Rift. This is one of the most actively spreading rifts in the world.
In addition to the large earthquake, which caused lots of building damage and also caused over a dozen deaths so far (sadly), there was recorded a tsunami on the tide gages in the region. I use the IOC website to obtain tide gage data. This is an excellent service. There are only a few national tide gage online websites that rival this one.
It is also highly likely that there were landslides or that there was liquefaction somewhere in the region. The USGS models i present below show a high likelihood for these earthquake triggered processes.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
(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).
Those Rifts
Regional Cross Sections
necking and asthenospheric upwelling have produced locally well-developed alkaline volcanism (e.g., Sardinia). Slab tear or detachment in the Calabria segment of Adria, as imaged through seismic tomography (Spakman and Wortel, 2004), is probably responsible for asthenospheric upwelling and alkaline volcanism in southern Calabria and eastern Sicily (e.g., Mount Etna). Modified from Séranne (1999), with additional data from Spakman et al. (1993); Doglioni et al. (1999); Spakman and Wortel (2004); Lentini et al. (this volume).
and extensional processes in the upper plate of north-dipping subduction zone(s) within the Tethyan realm. See text
for discussion.
Europe
General Overview
Earthquake Reports
Social Media
complicated tectonics
also a plot of tide gage data from the region
Arrival times as prediceted by #Tsunami–#HySEA#IzmirEarthquake pic.twitter.com/8UEwItsLal
Deniz suyu ilçeyi kapladı…
İzmir Seferihisar'da 6.6 büyüklüğündeki depremin ardından tsunami meydana geldi.#İzmir #deprem #izmirdedeprem #Tsunami pic.twitter.com/kCugei77Zj
Unwrapped data (below) easier to interpret. Main subsidence (red) is offshore N of Samos. pic.twitter.com/eGGCHL6LXx
complicated tectonics
also a plot of tide gage data from the region
1/n pic.twitter.com/cBn4sew2xx
Aftershock sequence of the M7.0 Western Turkey as it stands.
Catalogue: @LastQuake pic.twitter.com/5oUa0fyXpL
Data also on ARIA-share: https://t.co/CDz2xn2gFo pic.twitter.com/uu5iYqi6WA
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.
Earthquake Report (and Tsunami) Oaxaca, Mexico
The M 7.4 Oaxaca, Mexico Earthquake occurred along the megathrust fault interface (an “interplate” earthquake) based on our knowledge of the location of the fault, our calculation of the earthquake location, and the earthquake mechanisms prepared by seismologists (i.e. focal mechanisms or moment tensors).
I noticed that there is a down-first wave prior to the tsunami. This was observed at both stations (Acapulco and Salina Cruz). Dr. Costas Synolakis (USC) informed me that this is a well known phenomena called a “Leading Depression N-wave.” I mark the location of the Salina Cruz gage on the interpretive poster below.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
Earthquake Triggered Landslides
Mexico | Central America
General Overview
Earthquake Reports
Social Media
Calculated with @antandre71 pic.twitter.com/6hQFMV55EX
CERRADA LA CARRETERA OAXACA-ISTMO POR #Sismo 7.5
Waiting #sentinel1…
Surface projection of the slip distribution by @USGS superimposed on the quickly forward model on #ArcGis platform; white lines indicate #Slab2 depth boundaries. The seismogenic fault is also shown in 3D view map (magenta plain). pic.twitter.com/sm62EHfF8Z
This one below is a recording from SE England pic.twitter.com/6RRzPsHAGK
References:
Basic & General References
Specific References
Return to the Earthquake Reports page.