SCEC Award Number 11114 View PDF
Proposal Category Collaborative Proposal (Data Gathering and Products)
Proposal Title Characterization of Earthquake Slip Distribution on the Northern Coyote Creek Strand of the San Jacinto Fault Using LiDAR and Field Mapping
Investigator(s)
Name Organization
Thomas Rockwell San Diego State University Anand Pandey San Diego State University
Other Participants Brendon Walker
Mike Buga

Both students are funded on other projects but plan to assist with some of the field mapping
SCEC Priorities A1, A9, A3 SCEC Groups Geology, SHRA, EFP
Report Due Date 02/29/2012 Date Report Submitted N/A
Project Abstract
 The purpose of this project was to use LiDAR and field mapping to quantify the numerous small offsets along the northern Coyote Creek Fault (CCF) to resolve slip distribution in past events. We downloaded and processed the B4 LiDAR dataset (opentopography.org) and produced 0.25 m DEMs for the northern CCF using ESRI software. Using GoogleEarth Pro and the LiDAR shaded hillside relief maps as a base, we mapped the location of all recognizable fault strands and identified areas where small offsets are likely to be preserved. We then walked the northern 30 km of the CCF and identified, mapped, and measured small offsets in the field. The offsets were binned in 1 km segments and plotted as a function of the distance from the northwest end of the CCF. We interpret the smallest offsets along a stretch of the fault to represent displacement in the most recent event (MRE). The attached figure shows distinct clustering of offsets, which we interpret to represent slip in past earthquakes; we connected larger offsets that have about twice the amount of displacement as that interpreted for the MRE to reflect displacement in the past two events, and three times the MRE as representing slip in three events. These observations suggest that the northern ~30 km of the CCF fails with displacement in the 1-1.5 m per event range. Furthermore, displacement is generally increasing to the southeast, which suggests that the rupture in these past events extended considerably farther than mapped herein.
Intellectual Merit This project contributes to understanding the repeatability of past large earthquakes, a key issue in quantifying the predictability of future earthquakes. This study also contributed to SoSAFE and resolving the rupture history of the southern San Andreas and San Jacinto fault zones
Broader Impacts This project was used to train a visiting scientist from India, Anand Pandey, who has returned to India to conduct similar research. His training included learning to process and use LiDAR data, and interpret offset tectonic geomorphic features to resolve slip distribution in past earthquakes. We also used this project as a training ground for Rockwell's 2011 graduate class in neotectonics.
Exemplary Figure /Users/thomasrockwell/Desktop/SCEC CCF final report/CCF-slip distribution.jpg
Figure 4. Slip distribution determined from the reliable offsets (quality ranking based on narrowness of fault zone, distinctness of measured features, certainty in location of the fault) for the northern ~28 km of the Coyote Creek fault. Uncertainties indicated by the error bars. Note that offset amounts tend to cluster, suggesting rather characteristic behavior for the past several northern CCF events.