Publications
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Bayesian historical earthquake relocation: an example from the 1909 Taipei earthquake Bayesian historical earthquake relocation: an example from the 1909 Taipei earthquake
Locating earthquakes from the beginning of the modern instrumental period is complicated by the fact that there are few good-quality seismograms and what traveltimes do exist may be corrupted by both large phase-pick errors and clock errors. Here, we outline a Bayesian approach to simultaneous inference of not only the hypocentre location but also the clock errors at each station and the...
Authors
Sarah E. Minson, William H.K. Lee
Path durations for use in the stochastic‐method simulation of ground motions Path durations for use in the stochastic‐method simulation of ground motions
The stochastic method of ground‐motion simulation assumes that the energy in a target spectrum is spread over a duration DT. DT is generally decomposed into the duration due to source effects (DS) and to path effects (DP). For the most commonly used source, seismological theory directly relates DS to the source corner frequency, accounting for the magnitude scaling of DT. In contrast, DP...
Authors
David M. Boore, Eric M. Thompson
Pulverization provides a mechanism for the nucleation of earthquakes at low stress on strong faults Pulverization provides a mechanism for the nucleation of earthquakes at low stress on strong faults
An earthquake occurs when rock that has been deformed under stress rebounds elastically along a fault plane (Gilbert, 1884; Reid, 1911), radiating seismic waves through the surrounding earth. Rupture along the entire fault surface does not spontaneously occur at the same time, however. Rather the rupture starts in one tiny area, the rupture nucleation zone, and spreads sequentially along...
Authors
Karen R. Felzer
Drift issues of tall buildings during the March 11, 2011 M9.0 Tohoku earthquake, Japan - Implications Drift issues of tall buildings during the March 11, 2011 M9.0 Tohoku earthquake, Japan - Implications
One of the most significant effects of the M9.0 Tohoku, Japan earthquake of March 11, 2011 is the now well-known long duration (>10 minutes) shaking of buildings in Japan – particularly those in Tokyo (~350-375 km from the epicenter) and in places as far as Osaka (~770 km from the epicenter). Although none collapsed, the strong shaking caused many tall buildings not to be functional for...
Authors
Mehmet Çelebi, Izuru Okawa
Comparison of NGA-West2 directivity models Comparison of NGA-West2 directivity models
Five directivity models have been developed based on data from the NGA-West2 database and based on numerical simulations of large strike-slip and reverse-slip earthquakes. All models avoid the use of normalized rupture dimension, enabling them to scale up to the largest earthquakes in a physically reasonable way. Four of the five models are explicitly “narrow-band” (in which the effect...
Authors
Paul A. Spudich, Badie Rowshandel, Shrey Shahi, Jack W. Baker, Brian S-J Chiou
Adding fling effects to processed ground‐motion time histories Adding fling effects to processed ground‐motion time histories
Fling is the engineering term for the effects of the permanent tectonic offset, caused by a rupturing fault in the recorded ground motions near the fault. It is expressed by a one‐sided pulse in ground velocity and a nonzero final displacement at the end of shaking. Standard processing of earthquake time histories removes some of the fling effects that may be required for engineering...
Authors
Ronnie Kamai, Norman A. Abrahamson, Robert Graves
NGA-West2 Research Project NGA-West2 Research Project
The NGA-West2 project is a large multidisciplinary, multi-year research program on the Next Generation Attenuation (NGA) models for shallow crustal earthquakes in active tectonic regions. The research project has been coordinated by the Pacific Earthquake Engineering Research Center (PEER), with extensive technical interactions among many individuals and organizations. NGA-West2...
Authors
Yousef Bozorgnia, Norman A. Abrahamson, Linda Al Atik, Timothy D. Ancheta, Gail M. Atkinson, Jack W. Baker, Annemarie S. Baltay Sundstrom, David M. Boore, Kenneth W. Campbell, Brian S.J. Chiou, Robert B. Darragh, Steve Day, Jennifer Donahue, Robert W. Graves, Nick Gregor, Thomas C. Hanks, I. M. Idriss, Ronnie Kamai, Tadahiro Kishida, Albert Kottke, Stephen A. Mahin, Sanaz Rezaeian, Badie Rowshandel, Emel Seyhan, Shrey Shahi, Tom Shantz, Walter Silva, Paul A. Spudich, Jonathan P. Stewart, Jennie Watson-Lamprey, Kathryn Wooddell, Robert Youngs
Imaging P and S attenuation in the Sacramento-San Joaquin Delta region, northern California Imaging P and S attenuation in the Sacramento-San Joaquin Delta region, northern California
We obtain 3-D Qp and Qs models for the Delta region of the Sacramento and San Joaquin Rivers, a large fluvial-agricultural portion of the Great Valley located between the Sierra Nevada batholith and the San Francisco Bay - Coast Ranges region of active faulting. Path attenuation t* values have been obtained for P and S data from 124 distributed earthquakes, with a longer variable window...
Authors
Donna Eberhart-Phillips, Clifford Thurber, Jon Peter B. Fletcher
Geologic logs of geotechnical cores from the subsurface Sacramento-San Joaquin Delta, California Geologic logs of geotechnical cores from the subsurface Sacramento-San Joaquin Delta, California
This report presents and summarizes descriptive geologic logs of geotechnical cores collected from 2009–12 in the Sacramento–San Joaquin Delta, California, by the California Department of Water Resources. Graphic logs are presented for 1,785.7 ft of retained cores from 56 borehole sites throughout the Sacramento-San Joaquin Delta. Most core sections are from a depth of ~100–200 feet...
Authors
Katherine L. Maier, Daniel J. Ponti, John C. Tinsley, Emma Gatti, Mark Pagenkopp
High-frequency imaging of elastic contrast and contact area with implications for naturally observed changes in fault properties High-frequency imaging of elastic contrast and contact area with implications for naturally observed changes in fault properties
During localized slip of a laboratory fault we simultaneously measure the contact area and the dynamic fault normal elastic stiffness. One objective is to determine conditions where stiffness may be used to infer changes in area of contact during sliding on nontransparent fault surfaces. Slip speeds between 0.01 and 10 µm/s and normal stresses between 1 and 2.5 MPa were imposed during...
Authors
Kohei Nagata, Brian D. Kilgore, Nicholas M. Beeler, Masao Nakatani
Effects of 2010 Hurricane Earl amidst geologic evidence for greater overwash at Anegada, British Virgin Islands Effects of 2010 Hurricane Earl amidst geologic evidence for greater overwash at Anegada, British Virgin Islands
A post-hurricane survey of a Caribbean island affords comparisons with geologic evidence for greater overwash at the same place. This comparison, though of limited application to other places, helps calibrate coastal geology for assessment of earthquake and tsunami potential along the Antilles Subduction Zone. The surveyed island, Anegada, is 120 km south of the Puerto Rico Trench and is...
Authors
Brian F. Atwater, Zamara Fuentes, Robert B. Halley, Uri S. ten Brink, Martitia P. Tuttle
Paleoearthquakes at Frazier Mountain, California delimit extent and frequency of past San Andreas Fault ruptures along 1857 trace Paleoearthquakes at Frazier Mountain, California delimit extent and frequency of past San Andreas Fault ruptures along 1857 trace
Large earthquakes are infrequent along a single fault, and therefore historic, well-characterized earthquakes exert a strong influence on fault behavior models. This is true of the 1857 Fort Tejon earthquake (estimated M7.7–7.9) on the southern San Andreas Fault (SSAF), but an outstanding question is whether the 330 km long rupture was typical. New paleoseismic data for six to seven...
Authors
Katherine M. Scharer, Ray Weldon, Ashley Streig, Thomas Fumal