Publications
Educational Publications
Educational Publications
Selected publications about earthquakes In plain language.
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Seismic imaging beneath an InSAR anomaly in eastern Washington State: Shallow faulting associated with an earthquake swarm in a low-hazard area Seismic imaging beneath an InSAR anomaly in eastern Washington State: Shallow faulting associated with an earthquake swarm in a low-hazard area
In 2001, a rare swarm of small, shallow earthquakes beneath the city of Spokane, Washington, caused ground shaking as well as audible booms over a five‐month period. Subsequent Interferometric Synthetic Aperture Radar (InSAR) data analysis revealed an area of surface uplift in the vicinity of the earthquake swarm. To investigate the potential faults that may have caused both the...
Authors
William J. Stephenson, Jackson K. Odum, Charles W. Wicks, Thomas L. Pratt, Richard J. Blakely
Hydrothermal frictional strengths of rock and mineral samples relevant to the creeping section of the San Andreas Fault Hydrothermal frictional strengths of rock and mineral samples relevant to the creeping section of the San Andreas Fault
We compare frictional strengths in the temperature range 25–250 °C of fault gouge from SAFOD (CDZ and SDZ) with quartzofeldspathic wall rocks typical of the central creeping section of the San Andreas Fault (Great Valley sequence and Franciscan Complex). The Great Valley and Franciscan samples have coefficients of friction, μ > 0.35 at all experimental conditions. Strength is unchanged...
Authors
Diane E. Moore, David A. Lockner, Stephen H. Hickman
Scaling relation between earthquake magnitude and the departure time from P wave similar growth Scaling relation between earthquake magnitude and the departure time from P wave similar growth
We introduce a new scaling relation between earthquake magnitude (M) and a characteristic of initial P wave displacement. By examining Japanese K-NET data averaged in bins partitioned by Mw and hypocentral distance, we demonstrate that the P wave displacement briefly displays similar growth at the onset of rupture and that the departure time (Tdp), which is defined as the time of...
Authors
Shunta Noda, William L. Ellsworth
Faulting, damage, and intensity in the Canyondam earthquake of May 23, 2013 Faulting, damage, and intensity in the Canyondam earthquake of May 23, 2013
On Thursday evening, May 23, 2013 (0347 May 24 UTC), a moment magnitude (Mw) = 5.7 earthquake occurred northeast of Canyondam, California. A two-person team of U.S. Geological Survey scientists went to the area to search for surface rupture and to canvass damage in the communities around Lake Almanor. While the causative fault had not been identified at the time of the field survey...
Authors
K. Chapman, M.B. Gold, John Boatwright, J. Sipe, V. Quitoriano, D. Dreger, Jeanne Hardebeck
Gallery of melt textures developed in Westerly Granite during high-pressure triaxial friction experiments Gallery of melt textures developed in Westerly Granite during high-pressure triaxial friction experiments
Authors
Diane E. Moore, David A. Lockner, Brian D. Kilgore, Nicholas M. Beeler
Preliminary assessment of a previously unknown fault zone beneath the Daytona Beach sand blow cluster near Marianna, Arkansas Preliminary assessment of a previously unknown fault zone beneath the Daytona Beach sand blow cluster near Marianna, Arkansas
We collected new high‐resolution P‐wave seismic‐reflection data to explore for possible faults beneath a roughly linear cluster of early to mid‐Holocene earthquake‐induced sand blows to the south of Marianna, Arkansas. The Daytona Beach sand blow deposits are located in east‐central Arkansas about 75 km southwest of Memphis, Tennessee, and about 80 km south of the southwestern end of the...
Authors
Jackson K. Odum, Robert Williams, William J. Stephenson, Martitia P. Tuttle, Hadar Al-Shukri
Characterizing potentially induced earthquake rate changes in the Brawley Seismic Zone, southern California Characterizing potentially induced earthquake rate changes in the Brawley Seismic Zone, southern California
The Brawley seismic zone (BSZ), in the Salton trough of southern California, has a history of earthquake swarms and geothermal energy exploitation. Some earthquake rate changes may have been induced by fluid extraction and injection activity at local geothermal fields, particularly at the North Brawley Geothermal Field (NBGF) and at the Salton Sea Geothermal Field (SSGF). We explore this...
Authors
Andrea L. Llenos, Andrew J. Michael
Persistent slip rate discrepancies in the eastern California (USA) shear zone Persistent slip rate discrepancies in the eastern California (USA) shear zone
Understanding fault slip rates in the eastern California shear zone (ECSZ) using GPS geodesy is complicated by potentially overlapping strain signals due to many sub-parallel strike-slip faults and by inconsistencies with geologic slip rates. The role of fault system geometry in describing ECSZ deformation may be investigated with total variation regularization, which algorithmically...
Authors
Eileen Evans, Wayne R. Thatcher, Frederick Pollitz, Jessica R. Murray
Dense lower crust elevates long-term earthquake rates in the New Madrid seismic zone Dense lower crust elevates long-term earthquake rates in the New Madrid seismic zone
Knowledge of the local state of stress is critical in appraising intraplate seismic hazard. Inverting earthquake moment tensors, we demonstrate that principal stress directions in the New Madrid seismic zone (NMSZ) differ significantly from those in the surrounding region. Faults in the NMSZ that are incompatible with slip in the regional stress field are favorably oriented relative to...
Authors
William Brower Levandowski, Oliver S. Boyd, Leonardo Ramirez-Guzman
Rapid estimation of earthquake magnitude from the arrival time of the peak high-frequency amplitude Rapid estimation of earthquake magnitude from the arrival time of the peak high-frequency amplitude
We propose a simple approach to measure earthquake magnitude M using the time difference (Top) between the body‐wave onset and the arrival time of the peak high‐frequency amplitude in an accelerogram. Measured in this manner, we find that Mw is proportional to 2logTop for earthquakes 5≤Mw≤7, which is the theoretical proportionality if Top is proportional to source dimension and stress...
Authors
Shunta Noda, Shunroku Yamamoto, William L. Ellsworth
The Earthquake‐Source Inversion Validation (SIV) Project The Earthquake‐Source Inversion Validation (SIV) Project
Finite‐fault earthquake source inversions infer the (time‐dependent) displacement on the rupture surface from geophysical data. The resulting earthquake source models document the complexity of the rupture process. However, multiple source models for the same earthquake, obtained by different research teams, often exhibit remarkable dissimilarities. To address the uncertainties in...
Authors
P. Martin Mai, Danijel Schorlemmer, Morgan T. Page, Jean-Paul Ampuero, Kimiyuki Asano, Mathieu Causse, Susana Custodio, Wenyuan Fan, Gaetano Festa, Martin Galis, Frantisek Gallovic, Walter Imperatori, Martin Kaser, Dmytro Malytskyy, Ryo Okuwaki, Frederick Pollitz, Luca Passone, Hoby N. T. Razafindrakoto, Haruko Sekiguchi, Seok Goo Song, Surendra N. Somala, Kiran K. S. Thingbaijam, Cedric Twardzik, Martin van Driel, Jagdish C. Vyas, Rongjiang Wang, Yuji Yagi, Olaf Zielke
The Eastern California Shear Zone as the northward extension of the southern San Andreas Fault The Eastern California Shear Zone as the northward extension of the southern San Andreas Fault
Cluster analysis offers an agnostic way to organize and explore features of the current GPS velocity field without reference to geologic information or physical models using information only contained in the velocity field itself. We have used cluster analysis of the Southern California Global Positioning System (GPS) velocity field to determine the partitioning of Pacific-North America...
Authors
Wayne R. Thatcher, James C. Savage, Robert W. Simpson