Geophysical framework of the northern San Francisco Bay region, California

Geosphere
By: , and 

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Abstract

We use geophysical data to examine the structural framework of the northern San Francisco Bay region, an area that hosts the northward continuation of the East Bay fault system. Although this fault system has accommodated ∼175 km of right-lateral offset since 12 Ma, how this offset is partitioned north of the bay is controversial and important for understanding where and how strain is accommodated along this stretch of the broader San Andreas transform margin. Using gravity and magnetic data, we map these faults, many of which influenced basin formation and volcanism. Continuity of magnetic anomalies in certain areas, such as Napa and Sonoma Valleys, the region north of Napa Valley, and the region south of the Santa Rosa Plain, preclude significant (>10 km) offset. Much of the slip is partitioned around Sonoma and Napa Valleys and onto the Carneros, Rodgers Creek, and Green Valley faults. The absence of correlative magnetic anomalies across the Hayward–Rodgers Creek–Maacama fault system suggests that this system reactivated older basement structures, which appear to influence seismicity patterns in the region.

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Publication type Article
Publication Subtype Journal Article
Title Geophysical framework of the northern San Francisco Bay region, California
Series title Geosphere
DOI 10.1130/GES00510.1
Volume 6
Issue 5
Year Published 2010
Language English
Publisher The Geological Society of America
Contributing office(s) Geology and Geophysics Science Center
Description 27 p.
First page 594
Last page 620
Country United States
State California
Other Geospatial San Francisco Bay
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