HR: 08:00h
AN: G51D-01    [Abstracts]
TI: Deformation and Fault Slip Along Plate Boundaries - Exploiting the Variations Between Geodetic and Geologic Observations
AU: * Furlong, K P
EM: kevin@geodyn.psu.edu
AF: Geodynamics Research Group - Geosciences, 542 Deike Building Penn State University, University Park, PA 16802 United States
AU: Dixon, T H
EM: tdixon@rsmas.miami.edu
AF: RSMAS-MGG, 4600 Rickenbacker Cswy University of Miami, Miami, FL 33149 United States
AB: As our tools and techniques for making observations of fault slip and crustal deformation rates have improved, the variation among observations has been the focus of much discussion. The simple solutions - that one set of measurements is wrong and another right - in general is not a satisfactory answer. Rather, differences in well-constrained observations may reflect the realities of temporal and spatial patterns of plate boundary deformation. Along the Pacific - North America plate boundary there are several examples that highlight the potential to exploit the `discrepant' geologic/geodetic data to improve our understanding of plate boundary kinematics and dynamics. In each case the key is using modeling approaches that appropriately represent the geometries and processes acting on the plate boundary structure. Specifically we look at three components of the Pacific - North America plate boundary where differences between well-constrained geologic and well-constrained geodetic observations provide strong constraints on plate boundary behavior. The Eastern California Shear Zone (ECSZ) accommodates a large share (~ 25%) of the plate motion, yet how that motion is partitioned among the faults in the region is unclear. In this case geodetic data provides constraints on the deep-seated (lower crust/lithosphere) pattern of deformation that helps to limit possible scenarios of fault behavior. In Northern Baja California, fault geometry plays an important role in controlling the behavior differences between the geologic and geodetic results. Finally, in the San Francisco Bay area the lack of a geodetic signal in the case of several small fault segments that show a geologic record of activity - such as those that connect various of the major fault strands, may allow us to better define the seismic hazard. In this case the lack of a geodetic signal does not preclude a real earthquake hazard.
DE: 1209 Tectonic deformation (6924)
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
DE: 8150 Plate boundary: general (3040)
DE: 8158 Plate motions: present and recent (3040)
SC: Geodesy [G]
MN: Fall Meeting 2005