Résumé
Risks posed by potentially seismogenic geologic faults are difficult to evaluate where records of past ruptures are sparse. More problematic, these faults may be situated near population centers and economic hubs. For example, the Foothills Thrust Belt (FTB), composed of the Shannon-Monte Vista and Berrocal-Sargent thrust faults, underlies the western edge of Silicon Valley in the San Francisco Bay Area, and is thought to be capable of producing large earthquakes. This poses some of the highest risks to the region and, by extension, the national economy. Through geologic time, activity on these faults have built the >1.2-km-high Southern Santa Cruz Mountains (SSCM). Thus, the relief that has been uplifted by fault slip should contain information about the rate at which seismic moment is accruing, otherwise missing in traditional analysis of past fault behavior.