iPlex Lunch spring-2017

Distribution of slip rate & implications for earthquake ruptures within the so. San Andreas system

Differences between slip rates estimated for the San Andreas fault by geodetic versus geologic methods have sparked many new geologic slip rate estimates for this fault section over the past decade or so. These studies reveal that the southern San Andreas fault zone exhibits large variations in slip rate along strike, which can explain much of the previously noted differences between geologic and geodetic rate estimates. This talk will present new geologic slip rate estimates from Pitman Canyon, Badger Canyon and Plunge Creek along the San Bernardino section of the San Andreas fault, as well as work in progress at a slip rate site and paleoseismic site on the Banning strand of the San Andreas fault near North Palm Springs. The results show that the Holocene to latest Pleistocene slip rate on the San Bernardino and San Gorongio Pass sections of the San Andreas fault is quite low (<16 mm/yr), as compared to rates almost twice as fast on the Mojave section of the San Andreas fault and south of Indio. The slow slip rate on the San Bernardino and San Gorgonio Pass sections of the fault is likely due to plate boundary slip being accommodated by the San Jacinto fault and the Eastern California shear zone. The implications of these slip rate patterns for future earthquake ruptures on the San Andreas fault system remains poorly understood.