SCEC Award Number 10054 View PDF
Proposal Category Collaborative Proposal (Integration and Theory)
Proposal Title Geologic, Interseismic, and Non-tectonic Deformation in the Ventura Basin Region
Investigator(s)
Name Organization
Scott Marshall Appalachian State University Susan Owen National Aeronautics and Space Administration Gareth Funning University of California, Riverside
Other Participants
SCEC Priorities A2, A5, A3 SCEC Groups CDM, Geodesy, USR
Report Due Date 02/28/2011 Date Report Submitted N/A
Project Abstract
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Intellectual Merit This project contributes to the understanding of deformation in southern California by using a novel three-dimensional approach to simulate both interseismic and long-term deformation. Thus, this work will directly test whether any geologic/geodetic rate discrepancies exist in the western Transverse Ranges. SCEC has put considerable effort into creating the Community Fault Model (CFM), but few researchers have found innovative methodologies to test the CFM geometry. Our modeling approach utilizes the CFM geometry and offers a quantitative assessment of the ability of the CFM to reproduce variations in slip and interseismic deformation in southern California. Our continued work will help to determine the validity of the CFM configuration in the western Transverse Ranges, a region where all previous models utilize unrealistic two-dimensional planar fault geometries.
Previous geodetic studies of the western Transverse Ranges did not attempt to separate tectonic and non-tectonic motions (i.e. strain anomalies). Recent geodetic work in the Los Angeles basin suggests that many GPS sites have significant non-tectonic motions, which must be removed to reveal the true tectonic deformation rates. This work will determine the extent of non-tectonic contamination of GPS sites in the western Transverse ranges. Preliminary results suggest that the non-tectonic influences are mainly seasonal, and therefore do not greatly affect longer term (>3 years) estimates of velocity.
This study combines the removal of non-tectonic geodetic velocities with a novel three-dimensional mechanical model in order to simulate interseismic and long-term (1000’s of years) deformation on the system-level. This is the first mechanical modeling technique that has successfully been applied to the complex network of faults (i.e. the CFM) in southern California. Furthermore, this technique has shown that several proposed geodetic/geologic discrepancies are due to model simplifications, and are, therefore, probably not reliable.
Broader Impacts This work has fostered collaborations between researchers at the Jet Propulsion Laboratory, the University of California Riverside, and Appalachian State University. At Appalachian State University, PI Marshall has now begun training undergraduate students in GPS processing and dislocation modeling. These efforts are aimed to produce future researchers that are better prepared for graduate school and the research world. Also, by training undergraduate students, interest and understanding of earthquake science is promoted. The results of this work will have a greater impact on society by more accurately characterizing the slip rates of faults, which leads to better seismic hazard estimates and building codes.
Exemplary Figure N/A
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