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A FORTRAN program for calculating nonlinear seismic ground response
The program described here was designed for calculating the nonlinear seismic response of a system of horizontal soil layers underlain by a semi-infinite elastic medium representing bedrock. Excitation is a vertically incident shear wave in the underlying medium. The nonlinear hysteretic behavior of the soil is represented by a model consisting of simple linear springs and Coulomb friction element
Authors
William B. Joyner
Frequency response of the USGS short period telemetered seismic system and its suitability for network studies of local earthquakes
The USGS telemetered seismic system was intended primarily to record small to moderate earthquakes (magnitude 0 to 4) at distances of a few km to several hundred km. Its frequency response is such that the recorded background noise at a moderately quite Coast Range site has a relatively flat 'record' spectrum from about 1/3 Hz to about 20 Hz. With the system magnification set so that the backgroun
Authors
Jerry P. Eaton
In-situ measurements of seismic velocities in the San Francisco Bay Region; part III
Seismic wave velocities (compressional and shear) are important parameters for estimating the seismic response characteristics of various geologic units when subjected to strong earthquake ground shaking. Seismic velocities of various units often show a strong correlation with the amounts of damage following large earthquakes and have been used as a basis for certain types of seismic zonation stud
Authors
James F. Gibbs, Thomas E. Fumal, Roger D. Borcherdt, Edward F. Roth
Large landslides, composed of megabreccia, interbedded in Miocene basin deposits, southeastern Arizona
The landslides in the Kearny and El Capitan Mountain quadrangles, Pinal and Gila Counties, Ariz., are tabular or lens like masses of megabreccia enclosed in Miocene basin deposits. The megabreccias within individual slide blocks are composed of pervasively brecciated Precambrian and younger formations that remain in normal stratigraphic sequence, indicating that each landslide moved as a fairly co
Authors
Medora Louise Hooper Krieger
Preseismic and coseismic deformation associated with the Hollister, California, earthquake of November 28, 1974
The epicenter of the Hollister earthquake (ML = 5.1) of November 28, 1974, is located near the center of an 81‐line trilateration network which has been surveyed annually since 1971. Five lines in the neighborhood of the epicenter were surveyed just 2 days before the earthquake, and two other lines nearby were surveyed 48 days earlier. Although some of these measurements suggest a possible preeart
Authors
James C. Savage, Mary Ann Spieth, W. H. Prescott
Strain accumulation on the San Andreas Fault near Palmdale, California
Precise distance measurements of a 10×25 km 15‐station trilateration network that spans the San Andreas fault west of Palmdale, California, have been repeated annually in the period 1971–1975. The network appears to be deforming under simple uniform tensor shear of about 0.21±0.03 μstrain/yr with the direction of maximum right‐lateral shear parallel to the local strike of the San Andreas fault. Co
Authors
W. H. Prescott, James C. Savage
Evidence of post-Pleistocene faults on New Jersey Atlantic outer continental shelf
Recently obtained high-resolution seismic profiles (400-4,000-Hz band) show evidence of faults in shallow sedimentary strata near the edge of the Atlantic continental shelf off New Jersey. Apparent normal faults having a throw of about 1.5 m displace sediments to within 7 m of the sea floor. The faults appear to be overlain by undeformed horizontal beds of relatively recent age. Several faults 1 t
Authors
R. E. Sheridan, H. J. Knebel
Sclerochronology: a tool for interpreting past environments
X-radiographs of stony coral slabs reveal two types of annual density bands. Detailed studies of these bands in relation to known variations in air temperatures indicate that sclerochronology is a valid tool for documenting time sequences and changing environmental conditions on a coral reef.
Authors
J. Harold Hudson, Eugene A. Shinn, Robert B. Halley, Barbara Lidz
Effects of local geological conditions in the San Francisco Bay region on ground motions and the intensities of the 1906 earthquake
Measurements of ground motion generated by nuclear explosions in Nevada have been completed for 99 locations in the San Francisco Bay region, California. The recordings show marked amplitude variations in the frequency band 0.25 to 3.0 Hz that are consistently related to the local geological conditions of the recording site. The average spectral amplifications observed for vertical and horizontal
Authors
Roger D. Borcherdt, James F. Gibbs
Structure and evolution of Bering Sea shelf south of St. Lawrence Island
The virtually featureless Beringian shelf south of St. Lawrence Island is underlain structurally by at least 14 basins. Encompassing a total area of more than 300,000 sq km, most of the basins are either elongate structural sags, grabens, or half (asymmetric) grabens beneath the outer shelf. The regional trend of these basins is northwest, parallel with that of the continental margin. Two of the b
Authors
Michael S. Marlow, David W. Scholl, Alan K. Cooper, E. C. Buffington
Coral reef recovery in Florida and the Persian Gulf
Long-term observations and study of coral reef destruction by hurricanes in the Florida Keys show, surprisingly, that although corals are devastated on a grand scale during storms, recovery is rapid. Recovery occurs because of the widespread scattering of live fragments, many of which become growth sites of new colonies. Reef recovery from death by chilling in the Persian Gulf was well under way w
Authors
Eugene A. Shinn