Interseismic deformation and geologic evolution of the Death Valley Fault Zone

The Death Valley Fault Zone (DVFZ), located in southeastern California, is an active fault system with an evolved pull‐apart basin that has been deforming over the past 6 Myr. We present a study of the interseismic motion and long‐term stress accumulation rates to better understand the nature of both past and present‐day loading conditions of the DVFZ. Using a 3‐D semi‐analytic viscoelastic deformation model, combined with geodetic velocities derived from the Mobile Array of GPS for Nevada Transtension (MAGNET) network and the Southern California Earthquake Center (SCEC) Crustal Motion Map version 4 (CMMv4) GPS data, we establish parameters for interseismic slip rate and apparent locking depth for four DVFZ fault segments. Our preferred model provides good fit to the data (1.0 mm/yr and 1.5 mm/yr RMS misfit in the fault‐perpendicular and fault‐parallel directions, respectively) and yields apparent locking depths between 9.8–17.1 km and strike‐slip rates of 3–7 mm/yr for the segments. We also determine subsidence (0.5–0.8 mm/yr) and extension (1.0–1.2 mm/yr) rates in the pull‐apart basin region. With these parameters, we construct a DVFZ evolution model for the last 6 Myr that recreates the motion of the fault blocks involved in the formation of the present‐day geological structures in Death Valley. Finally, using Coulomb stress accumulation rates derived from our model (0.25–0.49 MPa/100 yr), combined with earthquake recurrence interval estimates of 500 to 2600 years, we assess present‐day seismic hazards with calculated moment magnitudes ranging from 6.7–7.7.