Earthquake Science Center
Publications
VS30 and Dominant Site Frequency (fd) as Provisional Station ML Corrections (dML) in California
New seismic stations added to a regional seismic network cannot be used to calculate local magnitude (ML">MLML) until a revised regionwide amplitude decay function is developed. Each station must record a minimum number of local and regional earthquakes that meet specific amplitude requirements prior to recalibration of the amplitude decay...
Yong, Alan; Cochran, Elizabeth S.; Andrews, Jennifer; Hudson, Kenneth; Antony Martin; Yu, Ellen; Herrick, Julie A; Dozal, Jessica Rainfall triggers more deep-seated landslides than Cascadia earthquakes in the Oregon Coast Range, USA
The coastal Pacific Northwest USA hosts thousands of deep-seated landslides. Historic landslides have primarily been triggered by rainfall, but the region is also prone to large earthquakes on the 1100-km-long Cascadia Subduction Zone megathrust. Little is known about the number of landslides triggered by these earthquakes because the last...
LaHusen, Sean R; Duvall, Alison R; Booth, Adam M; Grant, Alex R. R. ; Mishkin, Benjamin A; Montgomery, David R; Struble, William; Roering, Joshua J.; Wartman, Joseph Forecasting for a fractured land: A case study of the communication and use of aftershock forecasts from the Mw 7.8 2016 Kaikōura earthquake in Aotearoa New Zealand
Operational earthquake forecasts (OEFs) are represented as time‐dependent probabilities of future earthquake hazard and risk. These probabilities can be presented in a variety of formats, including tables, maps, and text‐based scenarios. In countries such as Aotearoa New Zealand, the U.S., and Japan, OEFs have been released by scientific...
Becker, Julia S.; Potter, Sally H.; McBride, Sara; Hudson-Doyle, Emma E.; Gerstenberger, Matthew; Christopherson, Anne-Marie Developing post-alert messaging for ShakeAlert, the earthquake early warning system for the West Coast of the United States of America
As ShakeAlert, the earthquake early warning system for the West Coast of the U.S., begins its transition to operational public alerting, we explore how post-alert messaging might represent system performance. Planned post-alert messaging can provide timely, crucial information to both emergency managers and ShakeAlert operators as well as...
McBride, Sara; Bostrom, Ann; Sutton, Jeannette; deGroot, Robert Michael; Baltay, Annemarie S.; Terbush, Brian; Bodin, Paul; Dixon, Maximilian; Holland, Emily; Arba, Ryan; Laustsen, Paul C.; Liu, Sophia; Vinci, Margaret A stress-similarity triggering model for aftershocks of the MW6.4 and MW7.1 Ridgecrest earthquakes
The July 2019 Mw">Mw 6.4 and 7.1 Ridgecrest earthquakes triggered numerous aftershocks, including clusters of off‐fault aftershocks in an extensional stepover of the Garlock fault, near the town of Olancha, and near Panamint Valley. The locations of the off‐fault aftershocks are consistent with the stress‐similarity model of triggering,...
Hardebeck, Jeanne L. Are the stress drops of small earthquakes good predictors of the stress drops of moderate-to-large earthquakes?
The stress drops of small earthquakes often exhibit spatial patterns of variability. If moderate and large earthquakes follow the same spatial patterns, the stress drops of possible future damaging earthquakes could be better predicted by considering the stress drops of nearby small events. Better stress drop predictability could reduce ground-...
Hardebeck, Jeanne L. Seismicity induced by massive wastewater injection near Puerto Gaitán, Colombia
Seven years after the beginning of a massive wastewater injection project in eastern Colombia, local earthquake activity increased significantly. The field operator and the Colombian Geological Survey immediately reinforced the monitoring of the area. Our analysis of the temporal evolution of the seismic and injection data together with our...
Molina, I; Velasquez, J.S.; Rubinstein, Justin; García-Aristizabal, A; Dionicio, V Laboratory electrical conductivity of marine gas hydrate
Methane hydrate was synthesized from pure water ice and flash frozen seawater, with varying amounts of sand or silt added. Electrical conductivity was determined by impedance spectroscopy, using equivalent circuit modeling to separate the effects of electrodes and to gain insight into conduction mechanisms. Silt and sand increase the conductivity...
Constable, Steven; Lu, Ryan; Stern, Laura A.; Du Frane, Wyatt L.; Roberts, Jeffery J. Localized fluid discharge by tensile cracking during the post-seismic period in subduction zones
It is thought that extensional structures (extensional cracks and normal faults) generated during the post-seismic period create fluid pathways that enhance the drainage of the subducting plate interface, thus reducing the pore pressure and increasing fault strength. However, it remains to be elucidated how much pore fluid pressure decreases by...
Otsubo, Makoto; Hardebeck, Jeanne L.; Miyakawa, Ayumu; Yamaguchi, Asuka; Kimura, Gaku Pseudo-prospective evaluation of UCERF3-ETAS forecasts during the 2019 Ridgecrest sequence
The 2019 Ridgecrest sequence provides the first opportunity to evaluate Uniform California Earthquake Rupture Forecast v.3 with epidemic‐type aftershock sequences (UCERF3‐ETAS) in a pseudoprospective sense. For comparison, we include a version of the model without explicit faults more closely mimicking traditional ETAS models (UCERF3‐NoFaults). We...
Savran, William J.; Werner, Maximillian J.; Marzocchi, W.; Rhoades, David A.; Jackson, David D.; Milner, Kevin R.; Field, Edward H.; Michael, Andrew J. Evidence of previous faulting along the 2019 Ridgecrest, California earthquake ruptures
The July 2019 Ridgecrest earthquake sequence in southeastern California was characterized as surprising because only ~35% of the rupture occurred on previously mapped faults. Employing more detailed inspection of pre-event high-resolution topography and imagery in combination with field observations, we document evidence of active faulting in the...
Thompson Jobe, Jessica; Philibosian, Belle; Chupik, Colin; Dawson, Timothy E.; Bennett, Scott E. K.; Gold, Ryan D.; Duross, Christopher; Ladinsky, Tyler C.; Kendrick, Katherine; Haddon, Elizabeth; Pierce, Ian; Swanson, Brian J.; Seitz, Gordon G. Factors influencing the probability of hydraulic fracturing induced seismicity in Oklahoma
Injection‐induced seismicity became an important issue over the past decade, and although much of the rise in seismicity is attributed to wastewater disposal, a growing number of cases have identified hydraulic fracturing (HF) as the cause. A recent study identified regions in Oklahoma where ≥75% of seismicity from 2010 to 2016 correlated...
Ries, Rosamiel; Brudzinski, Michael R.; Skoumal, Robert; Currie, Brian S.