SCEC Award Number 19171 View PDF
Proposal Category Collaborative Proposal (Data Gathering and Products)
Proposal Title High-Resolution Determination of Short-term Slip Rates, Southernmost San Andreas Fault
Investigator(s)
Name Organization
Lewis Owen University of Cincinnati Paula Figueiredo University of Cincinnati Thomas Rockwell San Diego State University Allen Gontz San Diego State University
Other Participants
SCEC Priorities 1a, 5c, 2a SCEC Groups Geology, SAFS
Report Due Date 04/30/2020 Date Report Submitted 04/30/2020
Project Abstract
 Very high-resolution aerial imagery along portions of the San Andreas Fault in the Mecca Hills and high-resolution DEMs reveals displaced channels with offsets ranging from 10s cm to ~90 m. These can be used to investigate slip per event in past earthquakes. Several of these offset channels are incised into fluvial terraces and we collected samples for dating from several of the terraces, with well-resolved amounts of displacement, inferred to correspond to slip in past earthquakes. The primary focus of this proposal was to date the samples that we collected and to write up the results for publication. The offset amounts are constrained with relatively low uncertainties, from the high- resolution DEM and field measurements, and consequently, these results should yield a well resolved Holocene slip rate, as well as a very short-term slip rate that we will correlate with the paleoseismic record. All of the samples were prepared in the University of Cincinnati (UC) OSL Laboratory during the Spring of 2019 ready for measuring in OSL readers. PIs Owen and Figueiredo moved from the UC to North Carolina State University (NCSU) in August 2019 and consequently Owen transfer the OSL laboratory to NCSU where the samples were ready for measurement. However, the laboratory shut down due to the COVID-19 crisis before the measurements were complete. The laboratory will be made immediately upon reopening of the lab once the global pandemic improves and we will update the final report.
Intellectual Merit This proposal directly addressed several SCEC priorities, including P1a (refining the geologic slip rates on southern California faults), P5c (combining patterns of earthquake occurrence and strain accumulation with paleoseismic observations of the last millennium) and P2a (contribute to determine what fraction of seismic-moment accumulation is relaxes by aseismic processes).
Broader Impacts This project provided early career scientist, Post-doctoral Researcher Paula Figueiredo, with field and laboratory experience in OSL dating methods and setting up a new OSL dating laboratory. It also provided her with the opportunity to mentor an undergraduate, Antonio Votor, in the OSL laboratory at the University of Cincinnati, and then graduate student Antonio Votor, and Daria Khashchevskaya in the newly developing OSL Laboratory at North Carolina State University. The experiences that Antonio Votor had in the OSL laboratory at the University of Cincinnati encouraged him to apply for graduate school. In addition, undergraduate and graduate students from San Diego State University were trained in field sampling for OSL dating. Paula Figureirdo presented much of the study in the weekly seminar series of Department of Marine, Earth, and Atmospheric Sciences at NC State in October 2019.
Exemplary Figure Figure 2