Preliminary velocity and resistivity models of the Loma Prieta earthquake region

Journal Article · Sun Jul 01 04:00:00 EDT 1990 · Geophysical Research Letters (American Geophysical Union); (USA)

DOI:https://doi.org/10.1029/GL017i008p01235· OSTI ID:5981009

Eberhart-Phillips, D; Michael, A J ^[1]; Labson, V F; Stanley, W D; Rodriguez, B D ^[2]

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1. Geological Survey, Menlo Park, CA (USA)
2. Geological Survey, Denver, CO (USA)

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, 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 (>1,000 ohm-m), high-velocity (6.4-6.7 km/s) zone between the San Andreas and Sargent faults may represent largely mafic intrusive rocks.

• OSTI ID: 5981009
• Journal Information: Geophysical Research Letters (American Geophysical Union); (USA), Journal Name: Geophysical Research Letters (American Geophysical Union); (USA) Vol. 17:8; ISSN 0094-8276; ISSN GPRLA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
AFTERSHOCKS
CALIFORNIA
CENOZOIC ERA
DEPTH
DIMENSIONS
EARTHQUAKES
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELECTRICAL SURVEYS
ELECTROMAGNETIC SURVEYS
EPICENTERS
FEDERAL REGION IX
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FORMATIONS
GEOLOGIC FRACTURES
GEOLOGIC MODELS
GEOLOGIC STRUCTURES
GEOPHYSICAL SURVEYS
MAGNETOTELLURIC SURVEYS
NATIONAL ORGANIZATIONS
NORTH AMERICA
PHYSICAL PROPERTIES
RESERVOIR ROCK
SEISMIC EVENTS
SURVEYS
TERTIARY PERIOD
THREE-DIMENSIONAL CALCULATIONS
TWO-DIMENSIONAL CALCULATIONS
US DOI
US GS
US ORGANIZATIONS
USA
VELOCITY