Late Pleistocene and Holocene Paleoearthquake Activity of the Olinghouse Fault Zone, Nevada

摘要

Paleoseismic trenching and fault surface trace mapping indicate that the Olinghouse fault zone, a northeast trending, left-lateral strike-slip fault located in the northern Walker Lane, Nevada, has been the source of multiple latest Pleistocene and Holocene surface-rupturing earthquakes. A trench exposure near the eastern end of the fault records two, and possibly three, earthquakes after 3360 ± 190 cal. yr B.P. and two trenches at the western end of the fault contain evidence for two earthquakes after 19,800 ± 630 cal. yr B.P., with the most recent earthquake occurring after 1935 ± 70 cal. yr B.P. The apparent higher frequency of recent earthquakes at the eastern end of the fault may reflect triggered slip on the Olinghouse fault zone due to earthquakes on the conjugate northwest-trending, right-lateral Pyramid Lake fault. Repeated late Pleistocene and Holocene earthquakes on the Olinghouse fault zone demonstrate that northwest-directed, right-lateral shear of the northern Walker Lane is accommodated in part by northeast-trending left-lateral faults.