HR: 16:30h
AN: G32C-03    [PDF]
TI: Dynamic Global Plate Motion Model from Continuous GPS Observations to Support PBO Objectives
AU: * Prawirodirdjo, L
EM: linette@josh.ucsd.edu
AF: Scripps Institution of Oceanography, IGPP 0225 9500 Gilman Drive, La Jolla, CA 92093-0225 United States
AU: Bock, Y
EM: ybock@ucsd.edu
AF: Scripps Institution of Oceanography, IGPP 0225 9500 Gilman Drive, La Jolla, CA 92093-0225 United States
AB: We estimate a recent plate motion model for sixteen major and minor tectonic plates based solely on analysis of continuous data and metadata from 104 globally distributed permanent GPS stations analyzed operationally and consistently by the Scripps Orbit and Permanent Array Center (SOPAC), spanning the period from January 1991 to July 2003. Euler vectors for the North America, Pacific, and Eurasia plates are particularly well determined and form a sound basis for achieving PBO scientific goals. Site positions estimated from 24 hours of GPS phase and pseudorange data are aligned day-by-day to the IGS realization of the ITRF2000 reference frame using a seven-parameter similarity transformation, thereby ensuring that the ITRF2000 No-Net-Rotation Condition is preserved and that our plate motion model is absolute. Linear velocities of a carefully selected set of stations are estimated from the position time series, along with annual and semi-annual fluctuations and position offsets due to GPS instrument changes. A white noise plus flicker noise model is applied to estimate realistic uncertainties for the site velocities, which are then propagated into the derived plate motion model parameters. We also examine the vertical velocities of the sites in the site selection process to ensure long-term site stability, identify anomalous site motions, and to look for coherent motions within each of the rigid plates. The plate motion model is updated on a regular (monthly) basis (hence, dynamic) to improve its precision and reliability, as well as to detect possible anomalous changes due to seismic activity near active plate boundaries as postulated by several investigators.
UR: http://sopac.ucsd.edu
DE: 1206 Crustal movements--interplate (8155)
DE: 1247 Terrestrial reference systems
DE: 3040 Plate tectonics (8150, 8155, 8157, 8158)
DE: 8155 Plate motions--general
DE: 8158 Plate motions--present and recent (3040)
SC: Geodesy [G]
MN: 2003 Fall Meeting