Slicing up the San Francisco Bay Area: Insights from regional block modeling of GPS data
Abstract
Utilizing a new compilation of GPS velocities for the San Francisco Bay Area, we present a 3-D block model to solve for the slip rates of individual fault segments within the San Andreas fault system. Block models employ similar assumptions to traditional dislocation modeling (deep dislocations representing plate-boundary deformation, elastic medium), but add the additional physical constraint that individual faults must form connected boundaries around coherent blocks. Our slip rate estimates have important implications for regional seismic hazard, but here we use our model as a case study to focus on the advantages and limitations of this simple block modeling. We describe the importance of global constraints on estimating regional slip rates, the use of heat flow and seismicity to provide a first order constraint on the the seismic/aseismic transition depth, and the ability to test different scenarios of fault connectivity when geologic data alone is ambiguous. We also discuss the fundamental challenge of discriminating between deep deformation on closely spaced faults and the difficulty of defining 3-D fault geometries.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2005
- Bibcode:
- 2005AGUSM.G21A..02D
- Keywords:
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- 1206 Crustal movements: interplate (8155);
- 1243 Space geodetic surveys;
- 7223 Seismic hazard assessment and prediction;
- 8010 Fractures and faults