Seismic Models of the Root of the Sierra Nevada

Science  05 Dec 1980:
Vol. 210, Issue 4474, pp. 1088-1094
DOI: 10.1126/science.210.4474.1088


Seismic waves generated by earthquakes or explosions show a delay in travel times as they propagate across the Sierra Nevada from all directions except that of the Nevada test site. Early arriving waves from the test site can be explained if they emerge through a rock layer with high seismic velocity from the sharp eastern edge of the Sierran root. Such a layer could be formed by the subducted ophiolite slab that crops out in the western Sierra Nevada foothills. A synthesis of all seismic data indicates that the Sierran root projects downward into the mantle to a depth of about 55 kilometers beneath the high Sierra.