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

Geophysical Research Letters
By: , and 

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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.

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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 10.1029/2003GL019363
Volume 31
Issue 12
Year Published 2004
Language English
Publisher American Geophysical Union
Description L12S03, 4 p.
Country United States
State California
City Parkfield
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