Publications
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ShakeAlert Earthquake Early Warning System Performance During the 2019 Ridgecrest Earthquake Sequence ShakeAlert Earthquake Early Warning System Performance During the 2019 Ridgecrest Earthquake Sequence
During July 2019, a sequence of earthquakes including a Mw6.4 foreshock and a Mw7.1 mainshock occurred near Ridgecrest, California. ShakeAlert, the U.S. Geological Survey (USGS) ShakeAlert public Earthquake Early Warning (EEW) system being developed for the U.S. West Coast, was operational during this time, though public alerting was only available within LA County. ShakeAlert created...
Authors
Angela Chung, Men-Andrin Meier, Jennifer Andrews, Maren Bose, Brendan Crowell, Jeffrey J. McGuire, Deborah Smith
Kinematics of fault slip associated with the July 4-6 2019 Ridgecrest, Californai earthquakes sequence Kinematics of fault slip associated with the July 4-6 2019 Ridgecrest, Californai earthquakes sequence
The 2019 Ridgecrest, California, earthquake sequence produced observable crustal deformation over much of central and southern California, as well as surface rupture over several tens of kilometers. To obtain a detailed picture of the fault slip involved in the 4 July M 6.4 foreshock and 6 July M 7.1 mainshock, we combine strong‐motion seismic waveforms with crustal deformation...
Authors
Frederick Pollitz, Jessica R. Murray, Jerry L. Svarc, Charles Wicks, Evelyn Roeloffs, Sarah E. Minson, Katherine M. Scharer, Katherine J. Kendrick, Kenneth W. Hudnut, Johanna Nevitt, Benjamin A. Brooks, David Mencin
New opportunities to study earthquake precursors New opportunities to study earthquake precursors
No abstract available.
Authors
M. E. Pritchard, R. M. Allen, T. W. Becker, M. D. Behn, E. E. Brodsky, R. Burgmann, C. Ebinger, J. T. Freymueller, M. C. Gerstenberger, B. Haines, Y. Kaneko, S. D. Jacobsen, N. Lindsey, Jeffrey J. McGuire, Morgan T. Page, S. Ruiz, M. Tolstoy, L. Wallace, W. R. Walter, W. Wilcock, H. Vincent
A maximum rupture model for the southern San Andreas and San Jacinto Faults California, derived from paleoseismic earthquake ages: Observations and limitations A maximum rupture model for the southern San Andreas and San Jacinto Faults California, derived from paleoseismic earthquake ages: Observations and limitations
Paleoseismic rupture histories provide spatiotemporal models of earthquake moment release needed to test numerical models and lengthen the instrumental catalog. We develop a model of the fewest and thus largest magnitude earthquakes permitted by paleoseismic data for the last 1,500 years on the southern San Andreas and San Jacinto Faults, California, USA. The largest geometric complexity...
Authors
Katherine M. Scharer, Doug Yule
Segmentation and supercycles: A catalog of earthquake rupture patterns from the Sumatran Sunda Megathrust and other well-studied faults worldwide Segmentation and supercycles: A catalog of earthquake rupture patterns from the Sumatran Sunda Megathrust and other well-studied faults worldwide
After more than 100 years of earthquake research, earthquake forecasting, which relies on knowledge of past fault rupture patterns, has become the foundation for societal defense against seismic natural disasters. A concept that has come into focus more recently is that rupture segmentation and cyclicity can be complex, and that a characteristic earthquake model is too simple to...
Authors
Belle E. Philibosian, Aron J. Meltzner
The potential of using dynamic strains in earthquake early warning applications The potential of using dynamic strains in earthquake early warning applications
We investigate the potential of using borehole strainmeter data from the Network of the Americas (NOTA) and the U.S. Geological Survey networks to estimate earthquake moment magnitudes for earthquake early warning (EEW) applications. We derive an empirical equation relating peak dynamic strain, earthquake moment magnitude, and hypocentral distance, and investigate the effects of...
Authors
Noha Sameh Ahmed Farghal, Andrew J Barbour, John Langbein
EERI earthquake reconnaissance report: 2019 Ridgecrest earthquake sequence EERI earthquake reconnaissance report: 2019 Ridgecrest earthquake sequence
The Ridgecrest Earthquake Sequence began the morning of 4 July 2019 with an M6.4 earthquake at 10:33 a.m., closely following several small foreshocks. The epicenter of this event was roughly 11 miles (18 km) east-northeast of Ridgecrest (Figure 1) within the Naval Air Weapons Station China Lake (NAWS-CL). Seismic and geologic data established that the M6.4 earthquake occurred primarily...
Authors
EERI Learning from Earthquakes Program, Katherine M. Scharer
California Historical Intensity Mapping Project (CHIMP): A consistently reinterpreted dataset of seismic intensities for the past 162 years and implications for seismic hazard maps California Historical Intensity Mapping Project (CHIMP): A consistently reinterpreted dataset of seismic intensities for the past 162 years and implications for seismic hazard maps
Historical seismic intensity data are useful for myriad reasons, including assessment of the performance of Probabilistic Seismic Hazard Assessment (PSHA) models and corresponding hazard maps by comparing their predictions to a dataset of historically observed intensities in the region. To assess PSHA models for California, a long and consistently interpreted intensity record is...
Authors
Leah Salditch, Molly M. Gallahue, Madeleine C. Lucas, James S. Neely, Susan E. Hough, Seth Stein
Direct evidence for fluid pressure, dilatancy, and compaction affecting slip in isolated faults Direct evidence for fluid pressure, dilatancy, and compaction affecting slip in isolated faults
Earthquake instability occurs as a result of strength loss during sliding on a fault. It has been known for over 50 years that fault compaction or dilatancy may cause significant weakening or strengthening by dramatically changing the fluid pressure trapped in faults. Despite this fundamental importance, we have no real understanding of the exact conditions that lead to compaction or...
Authors
Brooks P. Proctor, David A. Lockner, Brian D. Kilgore, Thomas M. Mitchell, Nicholas M. Beeler
Graphical Dispersion Plot Editor (DPE) for seismic-site characterization by using multiple surface-wave methods Graphical Dispersion Plot Editor (DPE) for seismic-site characterization by using multiple surface-wave methods
Introduction To understand the behavior of potentially damaging ground motions during earthquakes, seismic-site effects are routinely characterized by using the dispersion of surface waves. Many methods exist to measure dispersion; these methods have various advantages and disadvantages, but they all yield dispersion data that must be inverted for shear-wave velocity. This report...
Authors
Devin McPhillips, Alan K. Yong, Antony Martin, William J. Stephenson
Surface displacement distributions for the July 2019 Ridgecrest, California earthquake ruptures Surface displacement distributions for the July 2019 Ridgecrest, California earthquake ruptures
Surface rupture in the 2019 Ridgecrest, California, earthquake sequence occurred along two orthogonal cross faults and includes dominantly left‐lateral and northeast‐striking rupture in the Mw 6.4 foreshock and dominantly right‐lateral and northwest‐striking rupture in the Mw 7.1 mainshock. We present >650 field‐based, surface‐displacement observations for these ruptures and synthesize...
Authors
Christopher DuRoss, Ryan D. Gold, Timothy E. Dawson, Katherine M. Scharer, Katherine J. Kendrick, Sinan Akciz, Stephen J. Angster, Jeffery Bachhuber, Steven Bacon, Scott E.K. Bennett, Luke Blair, Benjamin A. Brooks, Thomas Bullard, W. Paul Burgess, Colin Chupik, Michael DeFrisco, Jaime Delano, James D. Dolan, Erik Frost, Nick Graehl, Elizabeth Haddon, Alexandra Elise Hatem, Janis Hernandez, Christopher S. Hitchcock, Kennth Hudnut, Jessica Thompson Jobe, Richard D Koehler, Ozgur Kozaci, Tyler C. Ladinsky, Christopher Madugo, Devin McPhillips, Christopher Milliner, Alexander Morelan, Brian Olson, Jason Patton, Belle E. Philibosian, Alexandra J. Pickering, Ian Pierce, Daniel J. Ponti, Gordon G. Seitz, Eleanor Spangler, Brian J. Swanson, Kate Thomas, Jerome Treiman, Francesca Valencia, Alana Williams, Robert Zinke
The 1933 Long Beach Earthquake (California, USA): Ground motions and rupture scenario The 1933 Long Beach Earthquake (California, USA): Ground motions and rupture scenario
We present a synoptic analysis of the ground motions from the 11 March 1933 Mw 6.4 Long Beach, California, earthquake, the largest known earthquake within the central Los Angeles Basin region. Our inferred shaking intensity pattern supports the association of the earthquake with the Newport-Inglewood fault; it further illuminates the concentration of severe damage in the town of Compton...
Authors
Susan E. Hough, Robert Graves