I propose to continue conducting detailed studies of active fault geometry along major fault systems in southern California. The primary focus would be to generate new, updated and refined 3D fault models of principal slip surfaces, and to incorporate these new fault surfaces into the CFM in collaboration with Andreas, Chris, John, Scott, and other members of the CFM Working Group. This includes evaluating hypocenters and focal mechanisms for active subsurface 3D fault geometry, developing new digital 3D fault surfaces for inclusion into the CFM, and evaluating competing alternative fault models with available independent datasets. As requested in the SCEC 2019 RFP and based on feedback from the Panel, a primary focus will be updating and improving the geometry of major faults that are incompletely or inaccurately represented in the current model (CFM 5.2). This includes developing new< representations for major faults still missing from the CFM, and revising faults whose 3D geometry still need further improvement yet whose fault representations have not been recently< updated. This includes faults like the White Wolf, offshore Hosgri, and several other major faults that have not been updated since CFM version 1.0. If time permits, another focus will be the Cajon Pass Earthquake Gate Area (EGA). Cajon Pass has been designated as the initial EGA site for targeted interdisciplinary research, and updating and improving the CFM 3D fault set in the Cajon Pass EGA has only just begun. These initial, preliminary fault models still need further testing and evaluation, other secondary faults that may be important interfaces or linking< structures at depth still need to be added, and possible alternative representations of major active faults, like the San Andreas, San Jacinto, Cucamonga, Cleghorn and others still need to be evaluated, updated and refined as more results from the Cajon Pass EGA initiative and new additional data in adjacent areas become available.
Lastly, given the size and complexity of the CFM 3D fault set, some coordinated effort is still needed to further develop, organize and manage the related CFM database and new, developing CFM web-based user interface. A portion of this project—together with a complimentary CFM project from Harvard—would thus support this continued, needed collaboration with Andreas, John, Scott Marshall (CXM Coordinator) and SCEC IT to further update, enhance and improve the CFM database, its new web-based interface, and the coordination and accessibility of the CFM with various model users, SCEC Working Groups and related CXM modeling initiatives.