We just had an earthquake in the Vanuatu region, along the New Hebrides subduction zone. This earthquake is at great depth and will most likely not produce a tsunami. The USGS magnitude is currently set at M = 7.3. UPDATE:…
San Francisco Bay: San Ramon Earthquake Swarm!
Those of you in the region of the San Francisco Bay are probably wondering what the likelihood that this recent and ongoing swarm of earthquakes in the San Ramon area may lead to a larger earthquake. I do not know,…
10/23/2015 Inaugural Cascadia GeoSciences Present
You’re invited to come network with old friends and colleagues, meet new ones, enjoy a locally-made beverage, maybe learn something and share your local knowledge with others. Cascadia GeoSciences presents: A Research Presentation by Todd B. Williams and Dr. Jason…
Cascadia subduction zone: Tectonic Earthquakes of the Pacific Northwest
IRIS and the US Geological Survey have recently produced an educational video about tectonic earthquakes in the region of the US Pacific Northwest. The project was funded by the National Science Foundation. The Video YT link for the embedded video…
Plate Tectonics: 200 Ma
Gibbons and others (2015) have put together a suite of geologic data (e.g. ages of geologic units, fossils), plate motion data (geometry of plates and ocean ridge spreading rates), and plate tectonic data (initiation and cessation of subduction or collision,…
Crescent City Tsunami Deposits: Sand Mine Marsh, 1700 A.D. Cascadia subduction zone earthquake generated tsunami
I collected some cores in the Crescent City region. The sedimentary evidence of the 1700 A.D. Cascadia subduction zone earthquake and tsunami is preserved in these cores. Watch the video below. Here is a composite of the two cores that…
2015.09.16 Chile Update #3
The aftershocks continue and will do so for weeks. Aftershocks from the 2011.03.27 Tohoku-Oki M 9.0 earthquake continue today. The decay rate for seismicity relates to characteristics of the fault called the b-value. The b-value can be determined/modeled in several…
Chile Historic Tsunami Comparisons
Here are three tsunami wave amplitude models from NOAA for three Great (magnitude > 8.0) earthquakes in Chile. Here are the USGS websites for the three earthquakes that generated these earthquakes, plus the one from 2015.09.16 not shown on the…
Chile M 8.3 Earthquake: Tsunami Observations!
Here are a couple of videos that document the arrival of tsunami waves in the “mouth of Genio river at Wafer Bay, Cocos Island, Costa Rica. Cocos Island is a National Park located between Galapagos Islands and the continental coast…
2015.09.16 Chile Update #1
Here are some updates to this earthquake and tsunami. First, here is an updated map. I have included an illustration from Atwater et al. (2005) that shows the earthquake cycle at a subduction zone. A subduction zone is a convergent…