Publications
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New Zealand’s deadliest quake sounds alarm for cities on fault lines
The catastrophic Christ Church Earthquake is a strong reminder to engineers and scientists of the hazards pose by fault lines, both mapped and unknown, near major cities. In February 2011, the relatively moderate earthquake that struck the cities of Christchurch and Lyttleton in the Canterbury region of New Zealand's South Island surprised many with its destructive power. The magnitude 6.2 temblor
Authors
Erol Kalkan
Seismic structure of the crust and uppermost mantle of South America and surrounding oceanic basins
We present a new set of contour maps of the seismic structure of South America and the surrounding ocean basins. These maps include new data, helping to constrain crustal thickness, whole-crustal average P-wave and S-wave velocity, and the seismic velocity of the uppermost mantle (Pn and Sn). We find that: (1) The weighted average thickness of the crust under South America is 38.17 km (standard de
Authors
Gary S. Chulick, Shane Detweiler, Walter D. Mooney
Thermodynamic method for generating random stress distributions on an earthquake fault
This report presents a new method for generating random stress distributions on an earthquake fault, suitable for use as initial conditions in a dynamic rupture simulation. The method employs concepts from thermodynamics and statistical mechanics. A pattern of fault slip is considered to be analogous to a micro-state of a thermodynamic system. The energy of the micro-state is taken to be the elast
Authors
Michael Barall, Ruth A. Harris
Validation of ground-motion simulations for historical events using SDoF systems
The study presented in this paper is among the first in a series of studies toward the engineering validation of the hybrid broadband ground‐motion simulation methodology by Graves and Pitarka (2010). This paper provides a statistical comparison between seismic demands of single degree of freedom (SDoF) systems subjected to past events using simulations and actual recordings. A number of SDoF syst
Authors
C. Galasso, F. Zareian, I. Iervolino, R.W. Graves
Timing of large earthquakes during the past 500 years along the Santa Cruz Mountains segment of the San Andreas fault at Mill Canyon, near Watsonville, California
A paleoseismic investigation across the Santa Cruz Mountains section of the San Andreas fault at Mill Canyon indicates that four surface‐rupturing earthquakes have occurred there during the past ~500 years. At this site, right‐lateral fault slip has moved a low shutter ridge across the mouth of the canyon, ponding latest Holocene sediments. These alluvial deposits are deformed along a narrow zone
Authors
Thomas E. Fumal
Contemporary seismicity in and around the Yakima-Fold-and-Thrust Belt in eastern Washington
We examined characteristics of routinely cataloged seismicity from 1970 to the present in and around the Yakima fold‐and‐thrust belt (YFTB) in eastern Washington to determine if the characteristics of contemporary seismicity provide clues about regional‐scale active tectonics or about more localized, near‐surface processes. We employed new structural and hydrologic models of the Columbia River bas
Authors
J. Gomberg, B. Sherrod, M. Trautman, E. Burns, Diane Snyder
Afterslip, tremor, and the Denali fault earthquake
We tested the hypothesis that afterslip should be accompanied by tremor using observations of seismic and aseismic deformation surrounding the 2002 M 7.9 Denali fault, Alaska, earthquake (DFE). Afterslip happens more frequently than spontaneous slow slip and has been observed in a wider range of tectonic environments, and thus the existence or absence of tremor accompanying afterslip may provide n
Authors
Joan Gomberg, Stephanie Prejean, Natalia Ruppert
Predominant-period site classification for response spectra prediction equations in Italy
We propose a site‐classification scheme based on the predominant period of the site, as determined from the average horizontal‐to‐vertical (H/V) spectral ratios of ground motion. Our scheme extends Zhao et al. (2006) classifications by adding two classes, the most important of which is defined by flat H/V ratios with amplitudes less than 2. The proposed classification is investigated by using 5%‐d
Authors
Carola Di Alessandro, Luis Fabian Bonilla, David M. Boore, Antonio Rovelli, Oona Scotti
Significant earthquakes on the Enriquillo fault system, Hispaniola, 1500-2010: Implications for seismic hazard
Historical records indicate frequent seismic activity along the north-east Caribbean plate boundary over the past 500 years, particularly on the island of Hispaniola. We use accounts of historical earthquakes to assign intensities and the intensity assignments for the 2010 Haiti earthquakes to derive an intensity attenuation relation for Hispaniola. The intensity assignments and the attenuation re
Authors
William H. Bakun, Claudia H. Flores, Uri S. ten Brink
Geomorphic and stratigraphic evidence for an unusual tsunami or storm a few centuries ago at Anegada, British Virgin Islands
Waters from the Atlantic Ocean washed southward across parts of Anegada, east-northeast of Puerto Rico, during a singular event a few centuries ago. The overwash, after crossing a fringing coral reef and 1.5 km of shallow subtidal flats, cut dozens of breaches through sandy beach ridges, deposited a sheet of sand and shell capped with lime mud, and created inland fields of cobbles and boulders. Mo
Authors
Brian F. Atwater, Uri S. ten Brink, Mark Buckley, Robert S. Halley, Bruce E. Jaffe, Alberto M. López-Venegas, Eduard G. Reinhardt, Maritia P. Tuttle, Steve Watt, Yong Wei
Seismic velocity model of the central United States (Version 1): Description and simulation of the 18 April 2008 Mt. Carmel, Illinois, Earthquake
We have developed a new three‐dimensional seismic velocity model of the central United States (CUSVM) that includes the New Madrid Seismic Zone (NMSZ) and covers parts of Arkansas, Mississippi, Alabama, Illinois, Missouri, Kentucky, and Tennessee. The model represents a compilation of decades of crustal research consisting of seismic, aeromagnetic, and gravity profiles; geologic mapping; geophysic
Authors
Leonardo Ramírez‐Guzmán, Oliver S. Boyd, Stephen H. Hartzell, Robert A. Williams
Evaluation of modal pushover-based scaling of one component of ground motion: Tall buildings
Nonlinear response history analysis (RHA) is now increasingly used for performance-based seismic design of tall buildings. Required for nonlinear RHAs is a set of ground motions selected and scaled appropriately so that analysis results would be accurate (unbiased) and efficient (having relatively small dispersion). This paper evaluates accuracy and efficiency of recently developed modal pushover–
Authors
Erol Kalkan, Anil K. Chopra