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North America-Pacific plate boundary, an elastic-plastic megashear - Evidence from very long baseline interferometryData obtained by Mark III VLBI measurements of radio signals from permanent and mobile VLBI sites for 5.5 years of observations, starting in October 1982, were used to derive a picture of the earth crust deformation near the North America-Pacific plate boundary. The data, which included the vector positions of the VLBI sites and their rate of change, were used for comparison with a number of lithospheric deformation models based upon the concept that the motions of points near the North America-Pacific plate boundary are a linear combination of North America and Pacific velocities. The best of these models were found to fit 95 percent of the variance in 139 VLBI length and transverse velocity observations. Instantaneous shear deformation associated with plate tectonics is apparently developing in a zone 450 km wide paralleling the San Andreas Fault; some of this deformation will be recovered through elastic rebound, while the rest will be permanently set through plastic processes. Because the VLBI data have not been collected for a significant fraction of the earthquake cycle, they cannot discriminate between elastic and plastic behaviors.
Document ID
19880059053
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Ward, Steven N.
(California, University Santa Cruz, United States)
Date Acquired
August 13, 2013
Publication Date
July 10, 1988
Publication Information
Publication: Journal of Geophysical Research
Volume: 93
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
88A46280
Funding Number(s)
CONTRACT_GRANT: NAG5-750
Distribution Limits
Public
Copyright
Other

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