Compression directions in southern California (from Santa Barbara to Los Angeles Basin) obtained from borehole breakouts
- Creators
- Wilde, Melita
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Stock, Joann
Abstract
Borehole elongation in 71 drill holes was used to infer breakout orientation and directions of maximum horizontal principal stress S_H for six areas west of the San Andreas fault in southern California: Santa Barbara, Ojai, Central Ventura Basin, East Ventura Basin, West Los Angeles Basin, and East Los Angeles Basin. Breakouts were determined from analysis of oriented four-arm caliper data. The breakouts form at the position of the maximum compressive stress on the borehole wall; if the borehole is vertical and parallel to one of the principal stress directions, the breakouts will form parallel to the minimum horizontal principal stress S_h orthogonal to the maximum horizontal principal stress S_H. Observations from deviated boreholes permit some constraints on the relative magnitudes of the principal stresses. In most cases the data permit either a thrust faulting (S_v
Additional Information
© 1997 American Geophysical Union. A Paper number 96JB03734. Received March 15, 1996; revised October 1, 1996; accepted November 27, 1996. Some data were graciously provided by J. Scott Hornafius and Laird Thompson of Mobil Exploration & Producing U.S. This work was supported by the Southern California Earthquake Center via NSF grant EAR 89-20136. Contribution 5656 of the Caltech Seismological Laboratory. SCEC publication 320. The early phases of this research were supported by the U.S. Geological Survey (USGS), Department of the Interior, under USGS award 1434-93-G-2297. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government. We thank Colleen Barton and an anonymous reviewer for very helpful reviews. Further details of the observations presented in this paper can be accessed on the internet at http://www.scecdc.scec.org/stress.Attached Files
Published - jgrb10903.pdf
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Additional details
- Eprint ID
- 44951
- Resolver ID
- CaltechAUTHORS:20140415-093934915
- Southern California Earthquake Center (SCEC)
- EAR 89-20136
- NSF
- 1434-93-G-2297
- USGS
- Created
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2014-04-15Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Seismological Laboratory, Division of Geological and Planetary Sciences
- Other Numbering System Name
- Southern California Earthquake Center
- Other Numbering System Identifier
- 320