Publications
Educational Publications
Educational Publications
Selected publications about earthquakes In plain language.
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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 drop is scal
Authors
Shunta Noda, Shunroku Yamamoto, William L. Ellsworth
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 earthquake‐so
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 Käser, Dmytro Malytskyy, Ryo Okuwaki, Fred 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
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 relative m
Authors
Wayne R. Thatcher, James C. Savage, Robert W. Simpson
Kinematic ground motion simulations on rough faults including effects of 3D stochastic velocity perturbations
We describe a methodology for generating kinematic earthquake ruptures for use in 3D ground‐motion simulations over the 0–5 Hz frequency band. Our approach begins by specifying a spatially random slip distribution that has a roughly wavenumber‐squared fall‐off. Given a hypocenter, the rupture speed is specified to average about 75%–80% of the local shear wavespeed and the prescribed slip‐rate func
Authors
Robert Graves, Arben Pitarka
Noise reduction in long‐period seismograms by way of array summing
Long‐period (>100 s period) seismic data can often be dominated by instrumental noise as well as local site noise. When multiple collocated sensors are installed at a single site, it is possible to improve the overall station noise levels by applying stacking methods to their traces. We look at the noise reduction in long‐period seismic data by applying the time–frequency phase‐weighted stacking
Authors
Adam T. Ringler, David C. Wilson, Tyler Storm, Benjamin T. Marshall, Charles R. Hutt, Austin Holland
Hydra—The National Earthquake Information Center’s 24/7 seismic monitoring, analysis, catalog production, quality analysis, and special studies tool suite
This report provides an overview of the capabilities and design of Hydra, the global seismic monitoring and analysis system used for earthquake response and catalog production at the U.S. Geological Survey National Earthquake Information Center (NEIC). Hydra supports the NEIC’s worldwide earthquake monitoring mission in areas such as seismic event detection, seismic data insertion and storage, sei
Authors
John M. Patton, Michelle R. Guy, Harley M. Benz, Raymond P. Buland, Brian K. Erickson, David S. Kragness
Fortnightly modulation of San Andreas tremor and low-frequency earthquakes
Earth tides modulate tremor and low-frequency earthquakes (LFEs) on faults in the vicinity of the brittle−ductile (seismic−aseismic) transition. The response to the tidal stress carries otherwise inaccessible information about fault strength and rheology. Here, we analyze the LFE response to the fortnightly tide, which modulates the amplitude of the daily tidal stress over a 14-d cycle. LFE rate i
Authors
Nicholas van der Elst, Andrew Delorey, David R. Shelly, Paul Johnson
Observations and modeling of fjord sedimentation during the 30 year retreat of Columbia Glacier, AK
To explore links between glacier dynamics, sediment yields and the accumulation of glacial sediments in a temperate setting, we use extensive glaciological observations for Columbia Glacier, Alaska, and new oceanographic data from the fjord exposed during its retreat. High-resolution seismic data indicate that 3.2 × 108 m3 of sediment has accumulated in Columbia Fjord over the past three decades,
Authors
Katherine B Love, Bernard Hallet, Thomas L. Pratt, Shad O'Neel
Coseismic slip and early afterslip of the 2015 Illapel, Chile, earthquake: Implications for frictional heterogeneity and coastal uplift
Great subduction earthquakes are thought to rupture portions of the megathrust, where interseismic coupling is high and velocity-weakening frictional behavior is dominant, releasing elastic deformation accrued over a seismic cycle. Conversely, postseismic afterslip is assumed to occur primarily in regions of velocity-strengthening frictional characteristics that may correlate with lower interseism
Authors
William D. Barnhart, Jessica R. Murray, Richard W. Briggs, Francisco Gomez, Charles P. J. Miles, Jerry L. Svarc, Sebástian Riquelme, Bryan J. Stressler
Responses of a tall building in Los Angeles, California as inferred from local and distant earthquakes
Increasing inventory of tall buildings in the United States and elsewhere may be subjected to motions generated by near and far seismic sources that cause long-period effects. Multiple sets of records that exhibited such effects were retrieved from tall buildings in Tokyo and Osaka ~ 350 km and 770 km from the epicenter of the 2011 Tohoku earthquake. In California, very few tall buildings have bee
Authors
Mehmet Çelebi, Hasan Ulusoy, Nori Nakata
Comparisons between vs30 and spectral response for 30 sites in Newcastle, Australia from collocated seismic cone penetrometer, active- and passive-source vs data
Although the time‐averaged shear‐wave velocity down to 30 m depth (VS30) can be a proxy for estimating earthquake ground‐motion amplification, significant controversy exists about its limitations when used as a single parameter for the prediction of amplification. To examine this question in absence of relevant strong‐motion records, we use a range of different methods to measure the shear‐wave ve
Authors
Theodora Volti, David Burbidge, Clive Collins, Michael W. Asten, Jackson K. Odum, William J. Stephenson, Chris Pascal, Josef Holzschuh
Granitic boulder erosion caused by chaparral wildfire: Implications for cosmogenic radionuclide dating of bedrock surfaces
Rock surface erosion by wildfire is significant and widespread but has not been quantified in southern California or for chaparral ecosystems. Quantifying the surface erosion of bedrock outcrops and boulders is critical for determination of age using cosmogenic radionuclide techniques, as even modest surface erosion removes the accumulation of the cosmogenic radionuclides and causes significant un
Authors
Katherine J. Kendrick, Camille Partin, Robert C. Graham