HR: 1340h
AN: T53A-1126    [Abstracts]
TI: Deformation of the Converging Juan de Fuca Plate Offshore Central Oregon
AU: * Chadwell, C
EM: cchadwell@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Drive, #0205, La Jolla, CA 92093, United States
AB: The Global Positioning System combined with acoustic ranging measured convergence of the Juan de Fuca and the North America plates 150 km offshore central Oregon to be 15.9 mm/yr at N73.6 E from 2000 to 2003. This is 50 % slower and rotated 25 degress more easterly than predicted by geomagnetic anomalies. The oceanic plate may deform here due to a combination of regional plate forces acting within the subduction zone between the obliquely converging, weaker, downgoing slab and the stronger, overidding Siletz Block in the forearc. The seafloor geodesy data and proposed mechanisms will be presented and examimed in the context of regional observations of on-land horizontal and vertical geodesy, forearc structure and faulting, seimsity, and other data.
DE: 1294 Instruments and techniques
DE: 3050 Ocean observatories and experiments
DE: 3060 Subduction zone processes (1031, 3613, 8170, 8413)
DE: 8158 Plate motions: present and recent (3040)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting