SCEC Award Number 08144 View PDF
Proposal Category Collaborative Proposal (Data Gathering and Products)
Proposal Title SoSAFE: Confirming and Extending the Event Record at Hog Lake, San Jacinto Fault
Investigator(s)
Name Organization
Thomas Rockwell San Diego State University Gordon Seitz San Diego State University
Other Participants Jeri Young
Tim Dawson
At least two SDSU graduate students
SCEC Priorities A1, A2 SCEC Groups EFP, SHRA, SoSAFE
Report Due Date 02/28/2009 Date Report Submitted N/A
Project Abstract
This proposal seeks funding to continue work on the earthquake history of the central San Jacinto fault at Hog Lake near Anza. In our previous SCEC and NEHRP-supported work, we excavated several trenches in the bottom of Hog Lake (dry in most years by July) and exposed a record of sixteen surface
ruptures extending back 3800 years. The length and richness of this record exceeded our expectations (we originally hoped to get 6-8 events and perhaps go back 2000 years), and the well-bedded peat-bearing section extends much deeper than we have currently excavated (6.5 m in the middle of the depression). The Ramona Band of Cahuilla Indians are planning an ecotourism center for the reservation (Hog Lake lies within the bounds of the Ramona Reservation), and their plans had been to have the Center on line by
now. Hence, we did not propose to continue this work last year. However, due to delays in their schedule, the Center is now due to open in Fall, 2008. Consequently, they have given approval for our paleoseismic investigations to continue for one additional year, to be concluded before September, 2008.
Intellectual Merit Accurately forecasting large earthquakes requires a complete record and understanding of short and long-term fault behavior. Do faults produce seismicity in a fairly “predictable” fashion (quasiperiodic, clustered) or is it largely independent of the elapsed time since the previous event (poissonian). Furthermore, the significance of fault interaction and the possible role of the San Andreas and San Jacinto faults in modulating regional seismicity are only now beginning to be addressed, and the significance of these factors in regional seismic production could be key elements. In California, the earthquake cycle for individual faults is too long to make historical observations of recurrence for a fault segment or group
of faults. Thus, we must rely on paleoseismology to develop observations of large earthquakes over long time periods and multiple earthquake cycles.
Broader Impacts N/A
Exemplary Figure N/A