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Risk-targeted versus current seismic design maps for the conterminous United States Risk-targeted versus current seismic design maps for the conterminous United States

The probabilistic portions of the seismic design maps in the NEHRP Provisions (FEMA, 2003/2000/1997), and in the International Building Code (ICC, 2006/2003/2000) and ASCE Standard 7-05 (ASCE, 2005a), provide ground motion values from the USGS that have a 2% probability of being exceeded in 50 years. Under the assumption that the capacity against collapse of structures designed for these
Authors
Nicolas Luco, Bruce R. Ellingwood, Ronald O. Hamburger, John D. Hooper, Jeffrey K. Kimball, Charles A. Kircher

Integrated geologic and geophysical studies of North American continental intraplate seismicity Integrated geologic and geophysical studies of North American continental intraplate seismicity

The origin of earthquakes within stable continental regions has been the subject of debate over the past thirty years. Here, we examine the correlation of North American stable continental region earthquakes using five geologic and geophysical data sets: (1) a newly compiled age-province map; (2) Bouguer gravity data; (3) aeromagnetic anomalies; (4) the tectonic stress field; and (5)...
Authors
X. Van Lanen, Walter D. Mooney

Two lithospheric profiles across southern California derived from gravity and seismic data Two lithospheric profiles across southern California derived from gravity and seismic data

We present two detailed 2-D density transects for the crust and uppermost mantle across southern California using a linear gravity inversion technique. This technique parameterizes the crust and upper mantle as a set of blocks that are based on published geologic and seismic models. Each block can have a range of densities that are constrained where possible by borehole measurements...
Authors
T. Romanyuk, Walter D. Mooney, Shane T. Detweiler

Writing on the walls: Geological context and early American spiritual beliefs Writing on the walls: Geological context and early American spiritual beliefs

Native American culture in many parts of California is preserved in fragmentary oral and conventional written histories, but also in sometimes dramatic petroglyphs and pictographs throughout the state. The symbolism of these images has been interpreted to reflect the natural environment, in particular issues related to rain. Although there is little doubt that rain was of paramount...
Authors
S. E. Hough

Report of the workshop on Extreme Ground Motions at Yucca Mountain, August 23-25, 2004 Report of the workshop on Extreme Ground Motions at Yucca Mountain, August 23-25, 2004

This Workshop has its origins in the probabilistic seismic hazard analysis (PSHA) for Yucca Mountain, the designated site of the underground repository for the nation's high-level radioactive waste. In 1998 the Nuclear Regulatory Commission's Senior Seismic Hazard Analysis Committee (SSHAC) developed guidelines for PSHA which were published as NUREG/CR-6372, 'Recommendations for...
Authors
Thomas C. Hanks, N. A. Abrahamson, M. Board, D.M. Boore, J.N. Brune, C.A. Cornell

Evaluation of some software measuring displacements using GPS in real-time Evaluation of some software measuring displacements using GPS in real-time

For the past decade, the USGS has been monitoring deformation at various locations in the western United States using continuous GPS. The main focus of these measurements are estimates of displacement averaged over one day. Essentially, these consist of recording at 30 seconds intervals the carrier-frequency phase-data (equivalent to travel-time) between a GPS receiver and the GPS...
Authors
John O. Langbein

Physical properties of two core samples from Well 34-9RD2 at the Coso geothermal field, California Physical properties of two core samples from Well 34-9RD2 at the Coso geothermal field, California

The Coso geothermal field, located along the Eastern California Shear Zone, is composed of fractured granitic rocks above a shallow heat source. Temperatures exceed 640 ?F (~338 ?C) at a depth of less than 10000 feet (3 km). Permeability varies throughout the geothermal field due to the competing processes of alteration and mineral precipitation, acting to reduce the interconnectivity of...
Authors
C.A. Morrow, D.A. Lockner
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