Assessing the role of the San Andreas fault in controlling the spatial distribution of erosion rates in the Transverse Ranges, Southern California

Abstract

In considering erosion rate controls, previous work has focused primarily on the geomorphic factors; here tectonic controls, particularly seismic shaking, are additionally considered, given the growing recognition that earthquakes may play a key role in generating landslides and erosion. We present new cosmogenic radionuclide data from the San Gabriel Mountains, combined with previously published data from the San Gabriel and San Bernardino Mountains, to resolve the parameters controlling erosion. Statistical analysis of erosion rate parameters reveals that one of the primary erosion rate controls in the San Gabriel and San Bernardino Mountains is catchment distance from the San Andreas fault, an analog for seismic shaking from the San Andreas fault. We hypothesize that seismically induced erosion plays a significant role in the sediment budget of the San Gabriel and San Bernardino Mountains.