thumbnail

Simulated ground motion in Santa Clara Valley, California, and vicinity from M ??? 6.7 scenario earthquakes

Bulletin of the Seismological Society of America

By:
, ,
DOI: 10.1785/0120060230

Links

Abstract

Models of the Santa Clara Valley (SCV) 3D velocity structure and 3D finite-difference software are used to predict ground motions from scenario earthquakes on the San Andreas (SAF), Monte Vista/Shannon, South Hayward, and Calaveras faults. Twenty different scenario ruptures are considered that explore different source models with alternative hypocenters, fault dimensions, and rupture velocities and three different velocity models. Ground motion from the full wave field up to 1 Hz is exhibited as maps of peak horizontal velocity and pseudospectral acceleration at periods of 1, 3, and 5 sec. Basin edge effects and amplification in sedimentary basins of the SCV are observed that exhibit effects from shallow sediments with relatively low shear-wave velocity (330 m/sec). Scenario earthquakes have been simulated for events with the following magnitudes: (1) M 6.8-7.4 Calaveras sources, (2) M 6.7-6.9 South Hayward sources, (3) M 6.7 Monte Vista/Shannon sources, and (4) M 7.1-7.2 Peninsula segment of the SAF sources. Ground motions are strongly influenced by source parameters such as rupture velocity, rise time, maximum depth of rupture, hypocenter, and source directivity. Cenozoic basins also exert a strong influence on ground motion. For example, the Evergreen Basin on the northeastern side of the SCV is especially responsive to 3-5-sec energy from most scenario earthquakes. The Cupertino Basin on the southwestern edge of the SCV tends to be highly excited by many Peninsula and Monte Vista fault scenarios. Sites over the interior of the Evergreen Basin can have long-duration coda that reflect the trapping of seismic energy within this basin. Plausible scenarios produce predominantly 5-sec wave trains with greater than 30 cm/sec sustained ground-motion amplitude with greater than 30 sec duration within the Evergreen Basin.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Simulated ground motion in Santa Clara Valley, California, and vicinity from M ??? 6.7 scenario earthquakes
Series title:
Bulletin of the Seismological Society of America
DOI:
10.1785/0120060230
Volume
98
Issue:
3
Year Published:
2008
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
1243
Last page:
1271