SCEC Award Number 21147 View PDF
Proposal Category Collaborative Proposal (Data Gathering and Products)
Proposal Title Slip rate of the Simi-Santa Rosa fault and related structures
Investigator(s)
Name Organization
Reed Burgette New Mexico State University Katherine Scharer United States Geological Survey
Other Participants Brian Schrotenboer, NMSU M.S. student
SCEC Priorities 1a, 3a, 2e SCEC Groups Geology, SAFS, SDOT
Report Due Date 03/15/2022 Date Report Submitted 03/29/2022
Project Abstract
 INTERIM REPORT

The goals of this project are to document late Quaternary deformation along the Simi-Santa Rosa fault through investigation of tectonic offsets along the fault, longer amplitude folding or tilting, and dating features cut by this fault. We have accomplished some of the central objectives of this project. One key product is a high-resolution point cloud model of topography of the area including Simi Valley and southern Santa Susana Mountains as it existed in 1947, prior to extensive urbanization. Current work is focused on measuring potential vertical deformation across the Simi-Santa Rosa fault (SSRF) using swaths extracted from the point cloud, and looking for markers of potential strike-slip deformation using the historic imagery and elevation data. Ages of prominent surfaces will be determined with pending radiocarbon analyses.
Intellectual Merit The landscape of Southern California has been extensively altered by development. This project demonstrates the ability to reconstruct a high resolution (~ 1 m) model of topography from archival aerial photos that predates much of the development. We are working to develop analysis strategies to measure late Quaternary deformation from the photogrammetric point cloud. Better resolving the slip rate of the Simi-Santa Rosa fault will contribute to our understanding of how plate boundary strain is accommodated in the southwestern Transverse Ranges and how seismic hazard is distributed in the region.
Broader Impacts This project is supporting training and research of a M.S. student at NMSU. The methods that we are adapting and developing will contribute to future work using high-resolution topography to measure tectonic deformation. The results of the slip rate investigation will contribute to more accurate hazard forecasts for this populated region.
Exemplary Figure Figure 1. Perspective view of the 1947 point cloud looking northeast across Simi Valley to the crest of the Santa Susana Mountains. The point cloud has over 300M points, and is colored by the grayscale value of photos used to construct the 3-D topography. The Simi-Santa Rosa fault makes the prominent break in slope between hills to the north and the agricultural Simi valley.