Publications

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...

The Satellite Telemetry Earthquake Monitoring Program was started in FY 1968 to evaluate the applicability of satellite relay telemetry in the collection of seismic data from a large number of dense seismograph clusters laid out along the major fault systems of western North America. Prototype clusters utilizing phone-line telemetry were then being installed by the National Center for...

The Chilean earthquake sequence of May 21–22, 1960, was accompanied by linear zones of tectonic warping, including both uplift and subsidence relative to sea level. The region involved is more than 200 km wide and about 1000 km long, and lies along the continental margin between latitude 37° and 48° S. Significant horizontal strains accompanied the vertical movements in parts of the...

An ultrasonic method for determining velocity has been developed that is independent of phase‐change errors due to reflection of specimen waves from coupling films. The method also eliminates the possibility of error due to conditions of nonhydrostatic stress at a specimen‐transducer or specimen‐delay line interface. Preliminary data are given for Alcoa 2024‐T4 aluminum and are compared...

A network of 64 seismic-refraction profiles recorded by the U.S. Geological Survey in California and Nevada and adjacent areas of Idaho, Wyoming, Utah, and Arizona from 1961 to 1963 was re-interpreted. From record sections compiled for all profiles, a basic travel-time diagram can be derived. In addition to the first arrivals on profiles in the Snake River Plain, the northern Basin and...