Structural Architecture of the Western Transverse Ranges and Potential for Large Earthquakes - Trishear Forward Models

Understanding the subsurface structure of the Western Transverse Ranges (WTR) is critical to assess the seismic potential of large thrust faults comprising this fold-and-thrust belt. Several models have been advanced over the years, building on new data and understandings of thrust belt architecture, but none of these efforts have incorporated the full range of data, including style and rates of late Quaternary deformation in conjunction with surface geology, sub-surface well data and offshore seismic data. In our models, we suggest that the nearly continuous backbone with continuous stratigraphy of the Santa Ynez Mountains is explained by a large anticlinorium over a deep structural ramp, and that the current thrust front is defined by the southward-vergent Pitas Point-Ventura fault. The Ventura Avenue anticline and trend is an actively deforming fault propagation fold over the partially blind Pitas Point-Ventura fault …