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Publications

Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center

Filter Total Items: 2543

Relatively simple through-going fault planes at large-earthquake depth may be concealed by the surface complexity of strike-slip faults Relatively simple through-going fault planes at large-earthquake depth may be concealed by the surface complexity of strike-slip faults

At the surface, strike-slip fault stepovers, including abrupt fault bends, are typically regions of complex, often disconnected faults. This complexity has traditionally led geologists studying the hazard of active faults to consider such stepovers as important fault segment boundaries, and to give lower weight to earthquake scenarios that involve rupture through the stepover zone...
Authors
Russell W. Graymer, Victoria E. Langenheim, Robert W. Simpson, Robert C. Jachens, David A. Ponce

Ages of Quaternary Rio Grande terrace-fill deposits, Albuquerque area, New Mexico Ages of Quaternary Rio Grande terrace-fill deposits, Albuquerque area, New Mexico

Results from luminescence dating on 13 samples from the Albuquerque area show that major-drainage fluvial deposits represent significant periods of aggradation that formed paired, correlatable terraces on the east and west margins of the Rio Grande valley . The youngest terrace fills (Primero Alto) formed during late Pleistocene as a result of streamflow variations with climate cooling...
Authors
Shannon Mahan, Byron D. Stone, Ralph R. Shroba

Basin structure beneath the Santa Rosa Plain, Northern California: Implications for damage caused by the 1969 Santa Rosa and 1906 San Francisco earthquakes Basin structure beneath the Santa Rosa Plain, Northern California: Implications for damage caused by the 1969 Santa Rosa and 1906 San Francisco earthquakes

Regional gravity data in the northern San Francisco Bay region reflect a complex basin configuration beneath the Santa Rosa plain that likely contributed to the significant damage to the city of Santa Rosa caused by the 1969 M 5.6, 5.7 Santa Rosa earthquakes and the 1906 M 7.9 San Francisco earthquake. Inversion of these data indicates that the Santa Rosa plain is underlain by two...
Authors
D.K. McPhee, V.E. Langenheim, S. Hartzell, R. J. McLaughlin, Brad T. Aagaard, R.C. Jachens, C. McCabe

Three-dimensional P wave velocity model for the San Francisco Bay region, California Three-dimensional P wave velocity model for the San Francisco Bay region, California

[1] A new three-dimensional P wave velocity model for the greater San Francisco Bay region has been derived using the double-difference seismic tomography method, using data from about 5,500 chemical explosions or air gun blasts and approximately 6,000 earthquakes. The model region covers 140 km NE-SW by 240 km NW-SE, extending from 20 km south of Monterey to Santa Rosa and reaching from...
Authors
C.H. Thurber, T.M. Brocher, H. Zhang, V.E. Langenheim

Formation of tectonic peperites from alkaline magmas intruded into wet sediments in the Beiya area, western Yunnan, China Formation of tectonic peperites from alkaline magmas intruded into wet sediments in the Beiya area, western Yunnan, China

Tertiary (3.78 Ma to 3.65 Ma) biotite-K-feldspar porphyritic bodies intrude Tertiary, poorly consolidated lacustrine sedimentary rocks in the Beiya mineral district in southwestern China. The intrusives are characterized by a microcrystalline and vitreous-cryptocrystalline groundmass, by replacement of some tabular K-feldspar phenocrysts with microcrystalline chlorite and calcite, and by...
Authors
Xing-Wang Xu, Xin-Ping Cai, Jia-You Zhong, Bao-Chang Song, Stephen G. Peters

Fault locking, block rotation and crustal deformation in the Pacific Northwest Fault locking, block rotation and crustal deformation in the Pacific Northwest

We interpret Global Positioning System (GPS) measurements in the northwestern United States and adjacent parts of western Canada to describe relative motions of crustal blocks, locking on faults and permanent deformation associated with convergence between the Juan de Fuca and North American plates. To estimate angular velocities of the oceanic Juan de Fuca and Explorer plates and...
Authors
Robert McCaffrey, Anthony I. Qamar, Robert W. King, Ray E. Wells, G. Khazaradze, C.A. Williams, C.W. Stevens, J.J. Vollick, P.C. Zwick

Regional Fluid Flow and Basin Modeling in Northern Alaska Regional Fluid Flow and Basin Modeling in Northern Alaska

The foothills of the Brooks Range contain an enormous accumulation of zinc (Zn) in the form of zinc sulfide and barium (Ba) in the form of barite in Carboniferous shale, chert, and mudstone. Most of the resources and reserves of Zn occur in the Red Dog deposit and others in the Red Dog district; these resources and reserves surpass those of most deposits worldwide in terms of size and...
Authors
Robert A. Ayuso, Robert Burruss, Julie A. Dumoulin, Garth E. Graham, Anita G. Harris, Craig A. Johnson, Karen D. Kelley, David L. Leach, Paul G. Lillis, Erin E. Marsh, Thomas E. Moore, Christopher J. Potter, John F. Slack
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