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Global Positioning System measurements of strain accumulation across the Imperial Valley, California - 1986-1989The Global Positioning System (GPS) data collected in southern California from 1986 to 1989 indicate considerable strain accumulation across the Imperial Valley. Displacements are computed at 29 stations in and near the valley from 1986 to 1988, and at 11 sites from 1988 to 1989. The earlier measurements indicate 5.9 =/- 1.0 cm/yr right-lateral differential velocity across the valley, although the data are heavily influenced by the 1987 Superstition Hills earthquake sequence. Some measurements, especially the east-trending displacements, are suspects for large errors. The 1988 to 1989 GPS displacements are best modeled by 5.2 =/- 0.9 cm/yr of valley crossing deformation, but rates calculated from conventional geodetic measurements (3.4 to 4.3 cm/yr) fit the data nearly as well. There is evidence from GPS and Very Long Base Interferometry (VLBI) observations that the present slip rate along the southern San Andreas fault is smaller than the long-term geologic estimate, suggesting a lower earthquake potential than is currently assumed. Correspondingly, a higher earthquake potential is indicated for the San Jacinto fault. The Imperial Valley GPS sites form part of a 183 station network in southern California and northern Baja California, which spans a cross-section of the North American-Pacific plate boundary.
Document ID
19920060788
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Larsen, Shawn
(California Institute of Technology Pasadena, United States)
Reilinger, Robert
(MIT Cambridge, MA, United States)
Date Acquired
August 15, 2013
Publication Date
June 10, 1992
Publication Information
Publication: Journal of Geophysical Research
Volume: 97
Issue: B6 J
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
92A43412
Funding Number(s)
CONTRACT_GRANT: USGS-14-08-001-G1774
CONTRACT_GRANT: USGS-14-08-001-G1354
CONTRACT_GRANT: NAG5-814
CONTRACT_GRANT: USGS-14-08-001-G1679
Distribution Limits
Public
Copyright
Other

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