Publications

The purpose of these experiments is to lay the groundwork for the implementation of subtractive compensation of the USGS seismic network tape playbacks utilizing the Develco model 6203 discriminators at a x1 playback speed. Although the Develco discriminators were designed for this application and a matching Develco compensation discriminator was purchased, effective use of this system...

No abstract available.

The Sixth Geodesy/Solid Earth and Ocean Physics (GEOP) Research Conwas held on February 4–5, 1974, at the Institute of Geophysics and Planetary Physics, University of California, San Diego, in La Jolla, California. It was attended by about 100 persons. James N. Brune, program chairman, opened the conference and delivered the introductory address, a somewhat extended version of which is...

Repeated surveys of a trilateration network (aperture greater than 20 km) centered on ground zero for the HANDLEY event, a nuclear explosion at the Nevada Test Site with yield in excess of 1 megaton, suggest that the explosion induced an east-west extension of the network by more than 50 mm. In the year following the detonation, this deformation reversed such that the final configuration

Measurements of lines of the California Geodimeter network in the vicinity of the epicenters of four 1972 earthquakes (magnitudes 4.7, 4.7, 4.8, and 5.1) along the San Andreas fault system indicate that no significant anomalous changes in line length preceded or accompanied those earthquakes. Within the precision of measurement, the data are consistent with a linear change in line length...

As part of a study of the environmental quality of San Francisco Bay, bottom material from 26 streams tributary to the Bay were analyzed for chlordane, DDD, DDE, DDT, and PCB residues. These compounds were present in essentially all streams tested. Chlordane proved to be ubiquitous, with a concentration range similar to that of the other compounds. Noteworthy was the occurrence in one...

The hypothesis of a fixed melting spot reference frame (M) for relative plate motion is tested in the northeastern Pacific Ocean, where the Kodiak-Bowie seamount chain intersects the northern triple junction between the Pacific, American, and Juan de Fuca plates. Available age determinations on Kodiak and Giacomini Seamounts provide an estimated average rate of volcanic propagation along...

Measurements of ground motion generated by nuclear explosions in Nevada have been completed for 99 locations in the San Francisco Bay region, California. The seismograms, Fourier amplitude spectra, spectral amplification curves for the signal, and the Fourier amplitude spectra of the seismic noise are presented for 60 locations. Analog amplifications, based on the maximum signal...

The U.S. Geological Survey conducts repeated geodimeter surveys of trilateration networks in central California in order to study the processes of slip and strain accumulation along the San Andreas fault. The precision of distance measurement is described by a standard deviation σ = (a2+ b2L2)12 where a = (a2+ b2L2)12 where a = 3mm, b = 2 · 10−7, and L is the line length. Within the...

On the basis of the newest interpretations of all sufficiently long seismic profiles, a contour map of the Mohorovičić discontinuity for the conterminous United States is compiled. Differences from earlier interpretations are discussed.

Seven years of seismic data recorded at the Uinta Basin Observatory were searched for earthquakes originating near an oil field at Rangely, Colorado, located 65 km ESE of the observatory. Changes in the number of earthquakes recorded per year appear to correlate with changes in the quantity of fluid injected per year. Between November 1962 and January 1970, 976 earthquakes were detected...

Convincing evidence that man can trigger earthquakes has been developed since the 1963–1967 report. The fact that man can start earthquakes has increased our understanding of earthquake mechanisms and reinforced our judgment that we are approaching the possibility of earthquake prediction. Traditionally, seismologists have avoided the subject of earthquake prediction because of its...