Publications
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Coral 13C/12C records of vertical seafloor displacement during megathrust earthquakes west of Sumatra
The recent surge of megathrust earthquakes and tsunami disasters has highlighted the need for a comprehensive understanding of earthquake cycles along convergent plate boundaries. Space geodesy has been used to document recent crustal deformation patterns with unprecedented precision, however the production of long paleogeodetic records of vertical seafloor motion is still a major challenge. Here
Authors
Michael K. Gagan, Sindia M. Sosdian, Heather Scott-Gagan, Kerry Sieh, Wahyoe S. Hantoro, Danny H. Natawidjaja, Richard W. Briggs, Bambang W. Suwargadi, Hamdi Rifai
Rapid characterization of the 2015 Mw 7.8 Gorkha, Nepal, earthquake sequence and its seismotectonic context
Earthquake response and related information products are important for placing recent seismic events into context and particularly for understanding the impact earthquakes can have on the regional community and its infrastructure. These tools are even more useful if they are available quickly, ahead of detailed information from the areas affected by such earthquakes. Here we provide an overview of
Authors
Gavin P. Hayes, Richard W. Briggs, William D. Barnhart, William L. Yeck, Daniel E. McNamara, David J. Wald, Jennifer Nealy, Harley M. Benz, Ryan D. Gold, Kishor S. Jaiswal, Kristin Marano, Paul S. Earle, Mike Hearne, Gregory M. Smoczyk, Lisa A. Wald, Sergey Samsonov
Seismic hazard in the eastern United States
The U.S. Geological Survey seismic hazard maps for the central and eastern United States were updated in 2014. We analyze results and changes for the eastern part of the region. Ratio maps are presented, along with tables of ground motions and deaggregations for selected cities. The Charleston fault model was revised, and a new fault source for Charlevoix was added. Background seismicity sources u
Authors
Charles Mueller, Oliver S. Boyd, Mark D. Petersen, Morgan P. Moschetti, Sanaz Rezaeian, Allison Shumway
The 1868 Hayward fault, California, earthquake: Implications for earthquake scaling relations on partially creeping faults
The 21 October 1868 Hayward, California, earthquake is among the best-characterized historical earthquakes in California. In contrast to many other moderate-to-large historical events, the causative fault is clearly established. Published magnitude estimates have been fairly consistent, ranging from 6.8 to 7.2, with 95% confidence limits including values as low as 6.5. The magnitude is of particul
Authors
Susan E. Hough, Stacey Martin
Seismic hazard in the Nation's breadbasket
The USGS National Seismic Hazard Maps were updated in 2014 and included several important changes for the central United States (CUS). Background seismicity sources were improved using a new moment-magnitude-based catalog; a new adaptive, nearest-neighbor smoothing kernel was implemented; and maximum magnitudes for background sources were updated. Areal source zones developed by the Central and Ea
Authors
Oliver S. Boyd, Kathleen Haller, Nicolas Luco, Morgan P. Moschetti, Charles Mueller, Mark D. Petersen, Sanaz Rezaeian, Justin L. Rubinstein
Ground motion models used in the 2014 U.S. National Seismic Hazard Maps
The National Seismic Hazard Maps (NSHMs) are an important component of seismic design regulations in the United States. This paper compares hazard using the new suite of ground motion models (GMMs) relative to hazard using the suite of GMMs applied in the previous version of the maps. The new source characterization models are used for both cases. A previous paper (Rezaeian et al. 2014) discussed
Authors
Sanaz Rezaeian, Mark D. Petersen, Morgan P. Moschetti
Low resistivity and permeability in actively deforming shear zones on the San Andreas Fault at SAFOD
The San Andreas Fault Observatory at Depth (SAFOD) scientific drillhole near Parkfield, California crosses the San Andreas Fault at a depth of 2.7 km. Downhole measurements and analysis of core retrieved from Phase 3 drilling reveal two narrow, actively deforming zones of smectite-clay gouge within a roughly 200 m-wide fault damage zone of sandstones, siltstones and mudstones. Here we report ele
Authors
Carolyn A. Morrow, David A. Lockner, Stephen H. Hickman
Seismic hazard in the Intermountain West
The 2014 national seismic-hazard model for the conterminous United States incorporates new scientific results and important model adjustments. The current model includes updates to the historical catalog, which is spatially smoothed using both fixed-length and adaptive-length smoothing kernels. Fault-source characterization improved by adding faults, revising rates of activity, and incorporating n
Authors
Kathleen Haller, Morgan P. Moschetti, Charles Mueller, Sanaz Rezaeian, Mark D. Petersen, Yuehua Zeng
Interpretation of S waves generated by near-surface chemical explosions at SAFOD
A series of near-surface chemical explosions conducted at the San Andreas Fault Observatory at Depth (SAFOD) were recorded by high-frequency downhole receiver arrays in separate experiments in November 2003 and May 2005. The 2003 experiment involved ∼100 kg shots detonated along a 46-km-long line (Hole–Ryberg line) centered on SAFOD and recorded by 32 three-component geophones in the pilot hole b
Authors
Fred F. Pollitz, William L. Ellsworth, Justin L. Rubinstein
Validation of simulated earthquake ground motions based on evolution of intensity and frequency content
Simulated earthquake ground motions can be used in many recent engineering applications that require time series as input excitations. However, applicability and validation of simulations are subjects of debate in the seismological and engineering communities. We propose a validation methodology at the waveform level and directly based on characteristics that are expected to influence most structu
Authors
Sanaz Rezaeian, Peng Zhong, Stephen H. Hartzell, Farzin Zareian
Strong-motion observations of the M 7.8 Gorkha, Nepal, earthquake sequence and development of the N-shake strong-motion network
We present and describe strong-motion data observations from the 2015 M 7.8 Gorkha, Nepal, earthquake sequence collected using existing and new Quake-Catcher Network (QCN) and U.S. Geological Survey NetQuakes sensors located in the Kathmandu Valley. A comparison of QCN data with waveforms recorded by a conventional strong-motion (NetQuakes) instrument validates the QCN data. We present preliminary
Authors
Amod Dixit, Adam T. Ringler, Danielle F. Sumy, Elizabeth S. Cochran, Susan E. Hough, Stacey Martin, Steven Gibbons, James H. Luetgert, John Galetzka, Surya Shrestha, Sudhir Rajaure, Daniel E. McNamara
The 2014 update to the National Seismic Hazard Model in California
The 2014 update to the U. S. Geological Survey National Seismic Hazard Model in California introduces a new earthquake rate model and new ground motion models (GMMs) that give rise to numerous changes to seismic hazard throughout the state. The updated earthquake rate model is the third version of the Uniform California Earthquake Rupture Forecast (UCERF3), wherein the rates of all ruptures are de
Authors
Peter M. Powers, Edward H. Field