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Crustal structure across the San Andreas Fault at the SAFOD site from potential field and geologic studies

Geophysical Research Letters

By:
, , and
DOI: 10.1029/2004GL019363

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Abstract

We present newly compiled magnetic, gravity, and geologic datasets from the Parkfield region around the San Andreas Fault Observatory at Depth (SAFOD) pilot hole in order to help define the structure and geophysical setting of the San Andreas Fault (SAF). A 2-D cross section of the SAF zone at SAFOD, based on new, tightly spaced magnetic and gravity observations and surface geology, shows that as drilling proceeds NE toward the SAF, it is likely that at least 2 fault bounded magnetic slivers, possibly consisting of magnetic granitic rock, serpentinite, or unusually magnetic sandstone, will be encountered. The upper 2 km of the model is constrained by an order of magnitude increase in magnetic susceptibility at 1400 m depth observed in pilot hole measurements. NE of the SAF, a flat lying, tabular body of serpentinite at 2 km depth separates two masses of Franciscan rock and truncates against the SAF.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Crustal structure across the San Andreas Fault at the SAFOD site from potential field and geologic studies
Series title:
Geophysical Research Letters
DOI:
10.1029/2004GL019363
Volume
31
Issue:
12
Year Published:
2004
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geophysical Research Letters