SCEC Award Number 10030 View PDF
Proposal Category Individual Proposal (Data Gathering and Products)
Proposal Title Use SAFOD Borehole Seismograph Records and Wenchuan Aftershock Data to Investigate Fault Rock Damage and Stress Status at Depth
Name Organization
Yong-Gang Li University of Southern California
Other Participants Dr. Elizabeth Cochran (UCR)
Dr. Po Chen (University of Wyoming)
2 SCEC Graduate Students
SCEC Priorities A8, A10, A11 SCEC Groups Seismology, FARM
Report Due Date 02/28/2011 Date Report Submitted N/A
Project Abstract
Intellectual Merit This project is a continuous effort to investigate near-fault crustal properties, evaluate fault structural complexity, and develop constraints on crustal structure and state of stress through a detailed study of the on- and near-fault damage and healing at the San Andreas fault (SAF) Parkfield and the Longmen-Shan Fault (LSF) in Sichuan, both of which ruptured in the recent major earthquakes. We extend the data sets collected from (1) the records at SAFOD mainhole (MH) and pilot-hole (PH) seismographs for ~350 aftershocks of the Parkfield M6 in Fall of 2004 and later, and (2) the records at 8 near-rupture stations for ~5,000 aftershocks of the 2008 M8 Wenchuan earthquake and hundreds of local earthquake recorded in 2006 to early 2008.

Through the funding support of SCEC, we have completed most part of our proposed research targets to further characterize and understand on- and near-fault damage extent at seismogenic depths in earthquake source region with strike-slipping and thrusting mechanisms, respectively.
Broader Impacts In this study, we focus on the properties of fault cores and damage zones along the SAF and LSF, and characterize their variability with depth and along strike to provide constraints for theoretical and laboratory studies, including width and particle composition of actively shearing zones, signatures of temperature variations, extent, origin and significance of on- and off-fault damage, healing, and poromechanical behavior (SCEC3 Science Priority Objectives A7-A11).
Exemplary Figure N/A