Publications
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Low strength of deep San Andreas fault gouge from SAFOD core
The San Andreas fault accommodates 28–34 mm yr−1 of right lateral motion of the Pacific crustal plate northwestward past the North American plate. In California, the fault is composed of two distinct locked segments that have produced great earthquakes in historical times, separated by a 150-km-long creeping zone. The San Andreas Fault Observatory at Depth (SAFOD) is a scientific borehole located
Authors
David A. Lockner, Carolyn A. Morrow, Diane E. Moore, Stephen H. Hickman
Pore-fluid migration and the timing of the 2005 M8.7 Nias earthquake
Two great earthquakes have occurred recently along the Sunda Trench, the 2004 M9.2 Sumatra-Andaman earthquake and the 2005 M8.7 Nias earthquake. These earthquakes ruptured over 1600 km of adjacent crust within 3 mo of each other. We quantitatively present poroelastic deformation analyses suggesting that postseismic fluid flow and recovery induced by the Sumatra-Andaman earthquake advanced the timi
Authors
K.L.H. Hughes, Timothy Masterlark, Walter D. Mooney
Earthquake casualty models within the USGS Prompt Assessment of Global Earthquakes for Response (PAGER) system
Since the launch of the USGS’s Prompt Assessment of Global Earthquakes for Response (PAGER) system in fall of 2007, the time needed for the U.S. Geological Survey (USGS) to determine and comprehend the scope of any major earthquake disaster anywhere in the world has been dramatically reduced to less than 30 min. PAGER alerts consist of estimated shaking hazard from the ShakeMap system, estimates o
Authors
Kishor Jaiswal, David J. Wald, Paul S. Earle, Keith A. Porter, Mike Hearne
Regional spectral analysis of three moderate earthquakes in Northeastern North America
We analyze Fourier spectra obtained from the horizontal components of broadband and accelerogram data from the 1997 Cap-Rouge, the 2002 Ausable Forks, and the 2005 Rivière-du-Loup earthquakes, recorded by Canadian and American stations sited on rock at hypocentral distances from 23 to 602 km. We check the recorded spectra closely for anomalies that might result from site resonance or source effect
Authors
John Boatwright, Linda C. Seekins
Spatiotemporal earthquake clusters along the North Anatolian fault zone offshore Istanbul
We investigate earthquakes with similar waveforms in order to characterize spatiotemporal microseismicity clusters within the North Anatolian fault zone (NAFZ) in northwest Turkey along the transition between the 1999 İzmit rupture zone and the Marmara Sea seismic gap. Earthquakes within distinct activity clusters are relocated with cross-correlation derived relative travel times using the double-
Authors
Fatih Bulut, William L. Ellsworth, Marco Bohnhoff, Mustafa Aktar, Georg Dresen
Modal-pushover-based ground-motion scaling procedure
Earthquake engineering is increasingly using nonlinear response history analysis (RHA) to demonstrate the performance of structures. This rigorous method of analysis requires selection and scaling of ground motions appropriate to design hazard levels. This paper presents a modal-pushover-based scaling (MPS) procedure to scale ground motions for use in a nonlinear RHA of buildings. In the MPS metho
Authors
Erol Kalkan, Anil K. Chopra
Connecting the Yakima fold and thrust belt to active faults in the Puget Lowland, Washington
High-resolution aeromagnetic surveys of the Cascade Range and Yakima fold and thrust belt (YFTB), Washington, provide insights on tectonic connections between forearc and back-arc regions of the Cascadia convergent margin. Magnetic surveys were measured at a nominal altitude of 250 m above terrain and along flight lines spaced 400 m apart. Upper crustal rocks in this region have diverse magnetic p
Authors
R. J. Blakely, B.L. Sherrod, C. S. Weaver, R. E. Wells, A.C. Rohay, E. A. Barnett, N.E. Knepprath
Structure of the San Fernando Valley region, California: implications for seismic hazard and tectonic history
Industry seismic reflection data, oil test well data, interpretation of gravity and magnetic data, and seismic refraction deep-crustal profiles provide new perspectives on the subsurface geology of San Fernando Valley, home of two of the most recent damaging earthquakes in southern California. Seismic reflection data provide depths to Miocene–Quaternary horizons; beneath the base of the Late Mioce
Authors
V. E. Langenheim, T. L. Wright, D. A. Okaya, R. S. Yeats, G. S. Fuis, K. Thygesen, H. Thybo
Detecting aseismic strain transients from seismicity data
Aseismic deformation transients such as fluid flow, magma migration, and slow slip can trigger changes in seismicity rate. We present a method that can detect these seismicity rate variations and utilize these anomalies to constrain the underlying variations in stressing rate. Because ordinary aftershock sequences often obscure changes in the background seismicity caused by aseismic processes, we
Authors
Andrea L. Llenos, Jeffrey McGuire
Seismic and geodetic signatures of fault slip at the Slumgullion Landslide Natural Laboratory
We tested the hypothesis that the Slumgullion landslide is a useful natural laboratory for observing fault slip, specifically that slip along its basal surface and side-bounding strike-slip faults occurs with comparable richness of aseismic and seismic modes as along crustal- and plate-scale boundaries. Our study provides new constraints on models governing landslide motion. We monitored landslide
Authors
J. Gomberg, W. Schulz, P. Bodin, J. Kean
Ground motion attenuation during M 7.1 Darfield and M 6.2 Christchurch, New Zealand, earthquakes and performance of global predictive models
The M 7.1 Darfield earthquake occurred 40 km west of Christchurch (New Zealand) on 4 September 2010. Six months after, the city was struck again with an M 6.2 event on 22 February local time (21 February UTC). These events resulted in significant damage to infrastructure in the city and its suburbs. The purpose of this study is to evaluate the performance of global predictive models (GMPEs) using
Authors
Margaret Segou, Erol Kalkan
Coulomb stress analysis of the 21 February 2008 Mw= 6.0 Wells, Nevada, earthquake
Static Coulomb stress changes imparted by the February 21, 2008 Wells, Nevada earthquake are calculated, using an 8 x 6 km rectangular patch with a uniform slip as a source fault. Stress changes are resolved on nearby active faults using their rake, dip, and strike direction, assuming a fault friction of 0.4. The largest Coulomb stress increase (0.2 bars) imparted to surrounding major active fault
Authors
Volkan Sevilgen