Project title tectonic geomorphic mapping, geochronology, and structural modeling of quaternary active faults in the santa maria basin, SAN louis obispo and santa barbara counties california…

Project title tectonic geomorphic mapping, geochronology, and structural modeling of quaternary active faults in the santa maria basin, SAN louis obispo and santa barbara counties california collaborative research with california state university long beach and lettis consultants international, INC.period of performance 4 1 2023 through 3 31 2024AWARD purpose the western transverse ranges (WTR) is a rapidly deforming mountain belt with several active faults, which pose a significant threat to metropolitan areas in southern and central california. Substantial geologic work has been done to determine how fast faults along the southern front of the WTR are building up stress and how they interact, but this has not been addressed for faults to the north, within the santa maria basin (SMB). GPS and geologic data suggest significant rates of active shortening across faults in the santa maria basin, however large uncertainties exist regarding their structural character, slip rate, and interconnectivity. This research aims to determine the geometry, kinematics and strain rate of major faults in the santa maria basin. To achieve the objectives of this study, detailed geomorphic mapping, documentation of fault offset, and luminescence age dating will be performed at sea cliff exposures of the lions head and santa ynez river faults. These data will be combined with a published database of dated late quaternary deposits and subsurface data in the WTR to produce four, spatially distributed cross sections that incorporate kinematic fault modeling. This study will provide updated and improved fault characterization with new age data for offset late pleistocene holocene surfaces across the four major faults located within the SMB. This will significantly improve our understanding of regional seismic hazard.activities to be performed 1. Perform site specific geomorphic and quaternary geologic mapping.2. Document fault exposures at each site and interpret exposed soils sediments and offsets, sampling for luminescence dating.3. Analyze samples in the csulb luminescence lab while concurrently integrating new geomorphic and quaternary geologic data to existing dataset.4. Compile surficial mapping and field measurements with subsurface data to develop four cross sections with 2D kinematic fault models of regional late quaternary deformation.5. Prepare final technical report (FTR), prepare data deliverables, and disseminate findings.deliverables and expected outcomes three primary deliverables will be generated by this study (1) quaternary geologic fault maps that will include new sedimentary dates and fault slip rate rates as well as our collection of previously published uplift rates from the WTR in a GIS based format (2) logs of natural fault exposures, including photomosaics and fault slip measurements (3) geolocated structural models for integration with community fault models. Deliverables will be reported included in the FTR. Intended beneficiaries data derived from these investigations will be useful to researchers in the fields of seismic hazard assessment and paleoseismology in southern and central california and will be imperative for the state and federal agencies to better evaluate the regional fault hazards.subrecipient activities N a