Seismic and Aseismic Moment Budget and Implication for the Seismic Potential of the Parkield Segment of the San Andreas Fault

Abstract:

This study explores methods to assess the seismic potential of a fault based on geodetic measurements, geological information of fault slip rate and seismicity data. The methods are applied to the Parkfield's section along the San Andreas Fault at the transition zone between the SAF creeping segment in the North and the locked section to the south, where a M_w~6 earthquake has occurred every 24.5 years on average since the M7.7 Fort Tejon event in 1857. We compare the moment released by all the known earthquakes and associated postseismic deformation with the moment deficit accumulated during the interseismic period. We find that the recurrence of M_w6 earthquakes is insufficient to close the slip budget and that larger events are probably needed. We will discuss and evaluate various possible scenarios which might account for the residual moment deficit and implications of the possible magnitude and return period of M_w6 earthquakes on that fault segment.