SCEC Award Number 12016 View PDF
Proposal Category Collaborative Proposal (Data Gathering and Products)
Proposal Title SoSAFE- San Jacinto: Evaluating slip distribution along the northern San Jacinto fault zone and the possibility of ruptures jumping across step-overs.
Investigator(s)
Name Organization
Nate Onderdonk California State University, Long Beach Sally McGill California State University, San Bernardino Tom Rockwell San Diego State University
Other Participants Scott Kenyon- MS student at CSU Long Beach
Ziad Sedki- MS student at CSU Long Beach
SCEC Priorities 2a, 2d, 4a SCEC Groups SoSAFE, Geology, FARM
Report Due Date 03/15/2013 Date Report Submitted N/A
Project Abstract
 For 2012, we received SCEC funding to map, describe, and measure offset features along the northern San Jacinto fault zone and the San Andreas fault in the San Bernardino area. The purpose of this work was to evaluate fault zone morphology and slip distribution to complement our recent slip rate, slip per event, and slip history data from the northern San Jacinto fault zone. By mapping the distribution of offset along the two faults, we hope to identify a geomorphic record of the last several earthquakes and possibly use this data to correlate events between paleoseismic sites. We also continued our work at the Mystic Lake paleoseismic site along the Claremont segment of the northern San Jacinto fault zone. Although the paleoseismic work was funded by a USGS EHP grant, it is part of ongoing SCEC research (and was supported by SCEC in previous years) and is reported here.
Intellectual Merit This project addresses several goals that are important for the SCEC4 mission. (1) Mapping of offsets along the northern San Jacinto fault zone will be used to estimate the slip-per-event for the most recent ruptures. This directly addresses an important SCEC4 objective described under priority 2a (improvement of earthquake catalogs). (2) These paleo-slip indicators and their distribution along strike may also be used as input to the community stress models (priority 2d). (3) Our new data from the Mystic Lake site also addresses SCEC4 priority 2a by providing a longer pre-historic earthquake record from the northern San Jacinto fault zone.
Broader Impacts This grant was used to support two graduate students who conducted the mapping and measurements of offset features using LiDAR and field techniques under the direction of Onderdonk. Both received training in LiDAR data manipulation and geomorphic mapping. One of these students attended the SoSAFE "fieldshop" last September on techniques for measuring offset features along faults and the other attended a SCEC/Open Topography LiDAR seminar. This project constituted the majority of the Masters thesis for both students and one has already presented his work at the GSA annual meeting last fall and has recently written his thesis and will graduate this coming June.
Trenching at Mystic Lake also involved students from CSULB, CSUSB, and SDSU in addition to several SCEC interns under the direction of McGill. One of these interns presented a poster at the SCEC annual meeting dealing with his work at Mystic Lake.
Exemplary Figure Figure 2. Comparison of the event histories from Mystic Lake with the Wrightwood (Fumal et al., 2002), Pitman Canyon (Seitz et al., 1997), Burro Flats (Yule, 2010), and Hog Lake (Rockwell, 2008) paleoseismic sites for the last 1600 years. See Figure 2 for site locations.