Constraining the kinematics of metropolitan Los Angeles faults with a slip-partitioning model

摘要

Due to the limited resolution at depth of geodetic and other geophysical data, the geometry and the loading rate of the ramp-decollement faults below the metropolitan Los Angeles are poorly understood. Here we complement these data by assuming conservation of motion across the Big Bend of the San Andreas Fault. Using a Bayesian approach, we constrain the geometry of the ramp-decollement system from the Mojave block to Los Angeles and propose a partitioning of the convergence with 25.5 +/- 0.5 mm/yr and 3.1 +/- 0.6 mm/yr of strike-slip motion along the San Andreas Fault and the Whittier Fault, with 2.7 +/- 0.9 mm/yr and 2.5 +/- 1.0 mm/yr of updip movement along the Sierra Madre and the Puente Hills thrusts. Incorporating conservation of motion in geodetic models of strain accumulation reduces the number of free parameters and constitutes a useful methodology to estimate the tectonic loading and seismic potential of buried fault networks.