Publications
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Provisional geologic map of Augustine Volcano, Alaska Provisional geologic map of Augustine Volcano, Alaska
No abstract available.
Authors
R. B. Waitt, J. E. Beget, Juergen Kienle
The Loma Prieta, California, Earthquake of October 17, 1989: Main shock characteristics The Loma Prieta, California, Earthquake of October 17, 1989: Main shock characteristics
The October 17, 1989, Loma Prieta, Calif., earthquake (0004:15.2 G.m.t. October 18; lat 37.036º N., long 121.883º W.; 19-km depth) had a local magnitude (ML) of about 6.7, a surface-wave magnitude (MS) of 7.1, a seismic moment of 2.2x1019 N-m to 3.5x1019 N-m, a source duration of 6 to 15 s, and an average stress drop of at least 50 bars. Slip occurred on a dipping fault surface about 35...
Authors
Paul A. Spudich, Gregory C. Beroza, George Choy, John Boatwright, Stephen H. Hartzell, Gordon L. Stewart, Carlos Mendoza, Stephen Horton, John G. Anderson, Andres J. Mendez, Hiroo Kanamori, Kenji Satake, Michael Lisowski, Mark Hunter Murray, Jerry L. Svarc, Grant Marshall, Ross S. Stein, Karen McNally, Gerald W. Simila, Judy G. Brown, J.L. Nabelek, Ze’ev Reches, Mark D. Zoback, Jamison Steidl, Ralph J. Archuleta, Aaron A. Velasco, Thorne Lay, Jiajun Zhang, David J. Wald, Donald V. Helmberger, Thomas H. Heaton, Chesley R. Williams, Paul Segall, Francis T. Wu, Mingdong Wu, J.W. Rudnicki
Seismic anisotropy of the crystalline crust: What does it tell us? Seismic anisotropy of the crystalline crust: What does it tell us?
The study of the directional dependence of seismic velocities (seismic anisotropy) promises more refined insight into mineral composition and physical properties of the crystalline crust than conventional deep seismic refraction or reflection profiles providing average values of P-and S-wave velocities. The alignment of specific minerals by ductile rock deformation, for instance, causes...
Authors
Wolfgang Rabbel, Walter D. Mooney
A new model for the emplacement of Columbia River basalts as large, inflated pahoehoe lava flow fields A new model for the emplacement of Columbia River basalts as large, inflated pahoehoe lava flow fields
Extensive flows of the Columbia River Basalt (CRB) Group in Washington, Oregon, and Idaho are dominantly inflated compound pahoehoe sheet lavas. Early studies recognized that CRB lavas are compound pahoehoe flows, with textures suggesting low flow velocities, but it was thought that the great thickness and extent of the major flows required very rapid emplacement as turbulent floods of...
Authors
S. Self, Th. Thordarson, L. Keszthelyi, G.P.L. Walker, K. Hon, M.T. Murphy, P. Long, S. Finnemore
Crater Lake National Park: Presently tranquil Crater Lake National Park: Presently tranquil
No abstract available.
Authors
Hans Nelson, Charles R. Bacon
U.S. East Coast EEZ: Part II U.S. East Coast EEZ: Part II
No abstract available.
Authors
James M. Robb, William P. Dillon, Dennis W. O'Leary, Peter Popenoe
The Lake Pontchartrain Basin: Louisiana's troubled urban estuary The Lake Pontchartrain Basin: Louisiana's troubled urban estuary
No abstract available.
Authors
S. Jeffress Williams
Compositional variations on the Moon: Recalibration of Galileo solid‐state imaging data for the Orientale region and farside Compositional variations on the Moon: Recalibration of Galileo solid‐state imaging data for the Orientale region and farside
Updated radiometric calibration and systematic processing procedures for Galileo solid‐state imaging (SSI) data from the first (1990) Earth‐Moon encounter are presented. These procedures were applied to a whole‐disk imaging sequence of the Moon centered near Mare Orientale, called Lunmap 14 (L14). Processing of L14 data included radiometric calibration, subpixel coregistration, scattered...
Authors
Lisa R. Gaddis, Alfred S. McEwen, Tammy L. Becker
Comparison of BASS and VACM current measurements during STRESS Comparison of BASS and VACM current measurements during STRESS
Current measurements from a vector-averaging current meter (VACM) on a subsurface mooring and a benthic acoustic stress sensor (BASS) on a bottom tripod are compared to assess their relative accuracy. The instruments were deployed off northern California at a midshelf site (water depth approximately 90 m) as part of the STRESS (Sediment Transport Events on Shelves and Slopes) field...
Authors
Steven J. Lentz, Bradford Butman, A. J. Williams
Strain accumulation across the central Nevada seismic zone, 1973–1994 Strain accumulation across the central Nevada seismic zone, 1973–1994
Five trilateration networks extending for 280 km along the central Nevada seismic zone (1915 Pleasant Valley, M = 7.3; 1954 Dixie Valley, M = 6.8; 1954 Stillwater, M = 6.8; 1954 Rainbow Mountain, M = 6.6; 1954 Fairview Peak, M = 7.1; and 1932 Cedar Mountain, M = 7.2) have been surveyed 6 times since 1973 to determine deformation along the zone. Within the precision of measurement the...
Authors
James C. Savage, Michael Lisowski, W.K. Gross
Changes in long‐term extension rates associated with the Morgan Hill and Loma Prieta earthquakes in California Changes in long‐term extension rates associated with the Morgan Hill and Loma Prieta earthquakes in California
Frequent measurements since mid‐1981 of the distances from a geodetic monument located about 100 km south‐southeast of San Francisco to three monuments 30 to 40 km distant provide an unusually complete record of the deformation before and after two nearby earthquakes, the 1984 Morgan Hill (ML = 6.2) and 1989 Loma Prieta (Ms = 7.1) earthquakes. Except possibly for the first few months...
Authors
James C. Savage, Michael Lisowski
Strain accumulation in Owens Valley, California, 1974 to 1988 Strain accumulation in Owens Valley, California, 1974 to 1988
Strain accumulation observed over the 1974 to 1988 interval in a 25 by 100 km aperture trilateration network spanning Owens Valley is adequately described by a strain rate that is uniform in space and time. The tensor strain-rate components referred to a coordinate system with the 2 axis directed N18°W (parallel to the trend of the valley) and the 1 axis N72°E are ∈˙11′ = 0.042 ± 0.014...
Authors
James C. Savage, Michael Lisowski