HOLOCENE RUPTURE HISTORY OF THE ASH HILL FAULT, EASTERN CALIFORNIA SHEAR ZONE
Fresh surface scarps without re-varnished surface clasts that offset the youngest, Qf7, surface are present for ~32km of fault length. Discontinuous scarps in Qf7 suggest that the most recent rupture may have occurred during Qf7 deposition, likely within the latest Holocene. At multiple locations, fault scarps in older Qf6a have at least twice the displacement as in adjacent Qf7 deposits, requiring at least one additional event since the middle Holocene. An older rupture that offsets Qf5 but not Qf6b requires a third event near the early Holocene. Measurements of surface offset indicate that single-event fault scarps are characterized by ~0.8 to 1.9 m of right lateral and ~0.2 to 0.4m of vertical displacement, while multi-event scarps are characterized by >0.7m of vertical displacement. Collectively, these new data indicate that the Ash Hill fault has produced multiple ~M 6.5-7 earthquakes during the Holocene, and may rupture at similar times as the nearby Panamint Valley and Owens Valley faults.