HR: 1340h
AN: G53A-0864    [Abstracts]
TI: Is the Elastic Half-Space Dislocation Model Appropriate for Estimating Far-Field Velocity?
AU: * Smith, B R
EM: brsmith@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr. MC 0225, La Jolla, CA 92093-0225 United States
AU: Sandwell, D T
EM: dsandwell@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr. MC 0225, La Jolla, CA 92093-0225 United States
AB: Geodetic velocities representing interseismic deformation are typically understood in terms of a simple arctangent function representing steady slip beneath a locked fault embedded in an elastic half-space. While this model is typically used to match far-field geologic observations, it is often too simple to provide an accurate representation of transient earthquake cycle effects such as postseismic deformation following large earthquakes. In an attempt to better understand the discrepancy between geologic observations and geodetically determined slip rates, we use a 3-D dislocation model consisting of an elastic plate overlying a Maxwell viscoelastic half-space to explore the nature of earthquake cycle velocities. First, we investigate the relationship of earthquake recurrence to Maxwell relaxation time to determine how quickly velocities may transition from an over-estimate to an under-estimate of the geologic velocity curve. For faults with earthquake recurrence times much greater than relaxation times, such as those suspected for much of the San Andreas Fault system, there is a greater probability of sampling rates appearing lower than the geologic arctangent estimate. Furthermore, because elastic plate models contain more deformation at distances far from the fault, it is possible that the velocity curve produced by these models is not well approximated by an arctangent function. Using synthetic data derived from an example elastic plate model, we explore alternate mathematical options for improving the fit to realistic model behavior.
DE: 1207 Transient deformation (6924, 7230, 7240)
DE: 1209 Tectonic deformation (6924)
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
DE: 3205 Fourier analysis (3255)
DE: 8158 Plate motions: present and recent (3040)
SC: Geodesy [G]
MN: Fall Meeting 2005