Skip to main content
U.S. flag

An official website of the United States government

Publications

Filter Total Items: 7604

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
Was this page helpful?