HR:     09:00h
AN:     G31A-03 INVITED
TI:     The Bay Area Regional Deformation (BARD) Permanent GPS 
        Network in Northern California
AU:     *Murray, M H
EM:     mmurray@seismo.berkeley.edu
AF:     Seismological Laboratory,
        Univ. of California Berkeley, CA 94720-4760  
AU:     *Murray, M H
EM:     mmurray@seismo.berkeley.edu
AF:     Geophysics Dept.,
        Stanford Univ.
         Stanford, CA 94305-2215  
AU:     B\"urgmann, R 
EM: 
AF:     Seismological Laboratory,
        Univ. of California Berkeley, CA 94720-4760  
AU:     Prescott, W H
EM: 
AF:     U.S. Geological Survey Menlo Park, CA 94025-3491  
AU:     Romanowicz, B 
EM: 
AF:     Seismological Laboratory,
        Univ. of California Berkeley, CA 94720-4760  
AU:     Schwartz, S 
EM: 
AF:     Earth Sci. Dept. \& Inst. Tectonics,
        Univ. California Santa Cruz, CA 95064  
AU:     Segall, P 
EM: 
AF:     Geophysics Dept.,
        Stanford Univ.
         Stanford, CA 94305-2215  
AU:     Silver, E 
EM: 
AF:     Earth Sci. Dept. \& Inst. Tectonics,
        Univ. California Santa Cruz, CA 95064  
AB:     The BARD network of permanent, continuously operating
        GPS receivers has monitored crustal deformation in the
        San Francisco Bay area and northern California since 1991.
        It presently includes over 35 permanent and
        semi-permanent stations installed
        and maintained by a large consortium of academic,
        commercial, and governmental institutions.
        Data are retrieved, quality checked, and publicly
        archived at the Northern California Earthquake Data Center,
        maintained by the Berkeley Seismological Laboratory (BSL).
        The BSL and USGS, Menlo Park analyze the data
        to determine daily site positions and their relative motions.
        Results from the longest operating stations
        suggest that the Great Valley is tectonically stable
        and that most of the $36 \pm 1$ mm/yr relative motion
        observed between the Sierra Nevada range and the Farallon
        Islands off the coast of San Francisco is accommodated
        by slip on the San Andreas Fault (SAF) system.
        These data are being combined with campaign-mode GPS and
        older VLBI and EDM measurements to constrain three-dimensional
        models of interseismic strain accumulation on the SAF system
        in the San Francisco Bay area for seismic hazard assessment.
        Our recent monitoring efforts are focussing on the
        Hayward and other east Bay faults that are considered
        among the most hazardous in the U.S., and on the recent
        volcanic unrest at Long Valley caldera.
        Data from 16 of the stations maintained by BSL are
        continuously telemetered in real-time, and we are developing
        methods to process and combine these data with seismic data,
        and to rapidly infer finite-fault parameters following major earthquakes
        to aid in hazard mitigation and emergency response activities.

DE:     1206  Crustal movements--interplate (8155)
DE:     1208  Crustal movements--intraplate (8110)
DE:     1294  Instruments and techniques
SC:     G
MN:     1998 Fall Meeting