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Preliminary velocity and resistivity models of the Loma Prieta Earthquake region

July 1, 1990

A preliminary three-dimensional velocity model of the Loma Prieta epicentral region in the Santa Cruz Mountains of California has been derived using raypaths from aftershocks recorded by the U.S.G.S. seismic network. In addition, a magnetotelluric sounding profile was completed prior to the earthquake and a two-dimensional resistivity model computed. The velocity and resistivity models include a low-resistivity (3–10 ohm-m), low-velocity (3.3–5.8 km/s) wedge of material between the Zayante and San Andreas faults that extends to depths of over 8 km and is interpreted to be largely Tertiary marine sedimentary rocks. A high-resistivity (>1000 ohm-m), high-velocity (6.4–6.7 km/s) zone between the San Andreas and Sargent faults may represent largely mafic intrusive rocks.

Citation Information

Publication Year 1990
Title Preliminary velocity and resistivity models of the Loma Prieta Earthquake region
DOI 10.1029/GL017i008p01235
Authors Donna Eberhart-Phillips, Victor F. Labson, William D. Stanley, Andrew J. Michael, Brian D. Rodriguez
Publication Type Article
Publication Subtype Journal Article
Series Title Geophysical Research Letters
Series Number
Index ID 70226729
Record Source USGS Publications Warehouse
USGS Organization Earthquake Science Center