Restraining segments and reactivation of the Santa Monica–Dume–Malibu Coast fault system, offshore Los Angeles, California

摘要

A regional west striking system of surface and blind faults transects northern metropolitan Los Angeles, separating the Santa Monica Mountains from two deep sedimentary basins. The surface faults include the Santa Monica, Dume, and Malibu Coast faults. The three-dimensional (3-D) geometries of these faults and deformed dated strata were examined in order to determine how oblique shortening is accommodated, how structural relief grows along a mountain front, and how block translation is related to block rotation. Industry seismic reflection, well, and outcrop data were used to construct digital structure-contour maps of several of these faults and three stratigraphic horizons that intersect them. These maps, swath bathymetry, digital elevation models, and seismicity were incorporated into a 3-D digital database. Modeling included new approaches to determining strike-slip displacement by separate analyses of shortening and structural relief in a restraining double bend.