Publications
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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-motion uncertainty in Probabilistic Seismic...
Authors
Jeanne L. Hardebeck
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 knowledge of the geological parameters of the...
Authors
I Molina, J.S. Velasquez, Justin L. Rubinstein, A García-Aristizabal, V Dionicio
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 of pure hydrate, we infer by contaminant...
Authors
Steven Constable, Ryan Lu, Laura A. Stern, Wyatt L. Du Frane, Jeffery J. Roberts
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 the extension crack formation. Here we...
Authors
Makoto Otsubo, Jeanne L. Hardebeck, Ayumu Miyakawa, Asuka Yamaguchi, Gaku Kimura
Procedures for developing multi-period response spectra at non-conterminous United States sites
This study complements proposals to the Provisions Update Committee of the Building Seismic Safety Council that would incorporate multi-period response spectra (MPRS) in the 2020 edition of the NEHRP Recommended Seismic Provisions for New Buildings and Other Structures (2020 NEHRP Provisions) and related proposals to the ASCE 7-22 Seismic Subcommittee of the American Society of Civil...
Authors
Mai Tong, Robert D. Hanson, Charles A. Kircher, Sanaz Rezaeian, Nico Luco
Calibration of the U.S. Geological Survey National Crustal Model
The U.S. Geological Survey National Crustal Model (NCM) is being developed to include spatially varying estimates of site response in seismic hazard assessments. Primary outputs of the NCM are continuous velocity and density profiles from the Earth’s surface to the mantle transition zone at 410-kilometer (km) depth for each location on a 1-km grid across the conterminous United States...
Authors
Oliver S. Boyd
Documentation of Surface Fault Rupture and Ground‐Deformation Features Produced by the 4 and 5 July 2019 Mw 6.4 and Mw 7.1 Ridgecrest Earthquake Sequence
The MwMw 6.4 and MwMw 7.1 Ridgecrest earthquake sequence occurred on 4 and 5 July 2019 within the eastern California shear zone of southern California. Both events produced extensive surface faulting and ground deformation within Indian Wells Valley and Searles Valley. In the weeks following the earthquakes, more than six dozen scientists from government, academia, and the private sector...
Authors
Daniel J. Ponti, J. Luke Blair, Rosa Carla M, Kate Thomas, Alexandra J. Pickering, Sinan Akçiz, Stephen J. Angster, Jean-Philipe Avouac, Jeffrey Bachhuber, Steven N. Bacon, Nicolas C. Barth, Scott E.K. Bennett, Kelly Blake, Stephan Bork, Benjamin A. Brooks, Thomas Bullard, Paul A. Burgess, Colin Chupik, Timothy E. Dawson, Michael DeFrisco, Jaime E. Delano, Stephen B. DeLong, James F. Dolan, Andrea Donnellan, Christopher DuRoss, Todd Ericksen, Erik Frost, Gareth J. Funning, Ryan D. Gold, Nicholas Graehl, Carlos I. Gutierrez, Elizabeth Haddon, Alexandra Elise Hatem, John Helms, Janis L. Hernandez, Christopher S. Hitchcock, Peter J. Holland, Kenneth W. Hudnut, Katherine J. Kendrick, Richard D Koehler, Ozgur Kozaci, Tyler C. Ladinsky, Robert Leeper, Christopher Madugo, Maxime Mareschal, James McDonald, Devin McPhillips, Christopher W. D. Milliner, Daniel Mongovin, Alexander E. Morelan, Stephanie Nale, Johanna Nevitt, Matt O'Neal, Brian J. Olsen, Michael E. Oskin, Salena Padilla, Jason R. Patton, Belle E. Philibosian, Ian Pierce, Cynthia L. Pridmore, Nathaniel Roth, David Sandwell, Katherine M. Scharer, Gordon G. Seitz, Drake Moore Singleton, Bridget Smith-Konter, Eleanor Spangler, Brian J. Swanson, Jessica Ann Thompson Jobe, Jerome A. Treiman, Francesca Valencia, Jeremy VanDerWal, Alana Williams, Xiaohua Xu, Judith Zachariasen, Jade Zimmerman, Robert Zinke
Recording the aurora borealis (northern lights) at seismometers across Alaska
We examine three continuously recording data sets related to the aurora: all‐sky camera images, three‐component magnetometer data, and vertical‐component, broadband seismic data as part of the EarthScope project (2014 to present). Across Alaska there are six all‐sky cameras, 13 magnetometers, and >200>200 seismometers. The all‐sky images and magnetometers have the same objective, which...
Authors
C. Tape, Adam T. Ringler, D.L. Hampton
Citizen science collaboration with the U.S. Geological Survey in Alaska
Citizen science is science undertaken by the public, usually in collaboration with professional scientific institutions. It encourages citizens to tackle real-world scientific problems and augments traditional science by expanding the coverage of data collection and by reducing costs of fieldwork in remote locations. Information collected by volunteers enables us all to gain a deeper...
Authors
Elizabeth Powers, Dee Williams
Global quieting of high-frequency seismic noise due to COVID-19 pandemic lockdown measures
Human activity causes vibrations that propagate into the ground as high-frequency seismic waves. Measures to mitigate the COVID-19 pandemic caused widespread changes in human activity, leading to a months-long reduction in seismic noise of up to 50%. The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record. While the...
Authors
Thomas Lecocq, Stephen Hicks, Koen Van Noten, Kasper van Wijk, Paula Koelemeijer, Raphael S.M. De Plaen, Frederick Massin, Gregor Hillers, Robert E. Anthony, Maria-Theresia Apoloner, Mario Arroyo-Solorzano, Jelle D. Assink, Pinar Buyukakpinar, Andrea Cannata, Flavio Cannavo, Sebastian Carrasco, Corentin Caudron, Esteban J. Chaves, David G. Cornwell, David Craig, Oliver F.C. den Ouden, Jordi Diaz, Stefanie Donner, Christos P. Evangelidis, Läslo G. Evers, Benoit Fauville, Gonzalo A. Fernandez, Dimitrios Giannopoulos, Steven J. Gibbons, Társilo Girona, Bogdan Grecu, Marc Grunberg, Gyorgy Hetenyi, Anna Horleston, Adolfo Inza, Jessica C.E. Irving, Mohammadreza Jamal-Reyhani, Alan Kafka, Mathijs R. Koymans, Celeste Labedz, Eric Larose, Nathaniel J. Lindsey, Mika McKinnon, Tobias Megies, Meghan S. Miller, William G. Minarik, Louis Moresi, Victor H. Marquez-Ramirez, Martin Mollhoff, Ian Nesbitt, Shankho Niyogi, Javier Ojeda, Adrien Oth, Simon Proud, Jeremy J. Pulli, Lise Retailleau, Annukka E. Rintamaki, Claudio Satriano, Martha Savage, Shanhar Shani-Kamiel, Reinoud Sleeman, Efthimios Sokos, Katie Stammler, Alexander E. Stott, Shiba Subedi, Mathilde B. Sørensen, Taka'aki Taira, Mar Tapia, Faith Turhan, Ben van der Pluijm, Mark Vanstone, Jerome Vernge, Tommi A.T. Vuorinen, Tristram Warren, Joachim Wassermann, Han Xiao
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 evaluate the forecasts with new metrics...
Authors
William J. Savran, Maximillian J. Werner, Warner Marzocchi, David A. Rhoades, David D. Jackson, Kevin R. Milner, Ned Field, Andrew J. Michael
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 landscape along the entire fault system...
Authors
Jessica Ann Thompson Jobe, Belle E. Philibosian, Colin Chupik, Timothy E. Dawson, Scott E.K. Bennett, Ryan D. Gold, Christopher DuRoss, Tyler C. Ladinsky, Katherine J. Kendrick, Elizabeth Haddon, Ian Pierce, Brian J. Swanson, Gordon G. Seitz