Quaternary geology and neotectonic activity along the Fish Lake Valley fault zone, Nevada and California

Abstract

The right-divergent Fish Lake Valley fault zone (FL VFZ), a 80 KM-long component of the northern Death Valley fault system, comprises contemporaneous NW-striking dextral faults, N-striking normal faults, NE-striking left(?)-divergent faults, and locally WNW-striking contractional faults. The fault zone terminate s in a horsetail splay where the minimum right-slip rate is 0 .7--0.8 mm/yr. The styles and rates of faulting are based on a sequence of morphostratigraphic units disrupted by the FL VFZ. Geomorphic surface correlation s, radiocarbon analyses, tephrochronology, and soil development studies were used to estimate unit ages. Paleoseismicity studies have identified three discrete slip events in the last 4 to 2 ka on the northern FL VFZ. The last two significant events were similar, suggesting a characteristic earthquake behavior and magnitude s of 7. 1 ± 0.3. The last large event occurred 1 ka (±0 .6, -0.5) and comparable events have repeated every 1. 1 Ka ( +2 . 3, -0.5 ). Source structure characteristics suggest a MCE of M 7.3 ± 0.4.