Publications
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Geomagnetic polarity epochs: age and duration of the olduvai normal polarity event Geomagnetic polarity epochs: age and duration of the olduvai normal polarity event
New data show that the Olduvai normal geomagnetic polarity event is represented in Olduvai Gorge, Tanzania, by rocks covering a time span of roughly from 0.1 to 0.2 my and is no older than 2.0 my. Hence the long normal polarity event of this age that is seen in deep-sea sediment cores and in magnetic profiles over oceanic ridges should be called the Olduvai event. The lava from which the
Authors
C. S. Grommé, R. L. Hay
Mechanism of the Chilean Earthquakes of May 21 and 22, 1960 Mechanism of the Chilean Earthquakes of May 21 and 22, 1960
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...
Authors
George Plafker, James C. Savage
Measurement of ultrasonic velocities in solids under hydrostatic pressure Measurement of ultrasonic velocities in solids under hydrostatic pressure
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...
Authors
L. Peselnick
Seismic refraction study of crustal structure in the western United States Seismic refraction study of crustal structure in the western United States
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...
Authors
Claus Prodehl