Adjunct Assitant Professor
Department of Earth Sciences
- Earthquake Physics
My research focuses on crustal deformation, earthquake triggering and near-fault structure, specifically related to earthquake physics. I employ a range of research methods, including statistical tests on earthquake catalogs, field acquisition and processing of seismic data, the use of space geodesy, and computational modeling to explain observations. Using data gathered during large seismic field deployments I investigate fault zone compliance, damage and healing associated with large earthquakes, and crustal anisotropy near active faults. In addition, I process, analyze, and model InSAR data acquired following large earthquakes to investigate postseismic deformation and recovery/relaxation processes. I also investigate triggering of earthquakes, specifically by Earth tides, to determine the lower limit of stress necessary to encourage a fault to fail. My research includes a range of projects and reflects the advantages gained by examining a problem from several perspectives.
My current studies focus on collecting and analyzing seismic data along active faults to determine fault structure as well as searching for seismic tremor in volcanic regions. To map the shallow and deep fault structure, nearly 100 seismometers were deployed along a section of the Calico Fault in the Mojave desert near Barstow, Calif. that exhibited anomalous strain in response to the 1992 Landers (M= 7.3) and 1999 Hector Mine (M=7.1) earthquakes. These data indicate that fault damage zones may be much wider than previously believed. Therefore, faults may affect rock properties at significant distances from the actual fault slip surfaces, a result likely to have implications for the partitioning of the stress buildup that leads to large earthquakes. Future work is planned on the Calico fault to compare the surface mapping of damage in the form of cracks and small block rotations with reductions in shallow seismic velocities. In addition, eight seismometers are currently deployed along the Superstition Hills fault to record seismic activity associated with episodes of accelerated creep along the fault that begin in October, 2006. This is a subset of work planned with the goal of assessing whether tremor or atypical seismic signals are associated with faults in Southern California.
Ph.D., University of California, Los Angeles, 2005
- Cochran, E.S. and J.E. Vidale, Letter to Editor, Comment on: Tidal synchronicity of the 26 December 2004 Sumatran earthquake and its aftershocks, GRL, submitted, 2007.
- Li, Y.-G., P. Chen, E.S. Cochran, J.E. Vidale, Seismic variations on the San Andreas fault caused by the 2004 M6 Parkfield earthquake and their implications, EPS, in press, 2007.
- Cochran, E.S., P.M. Shearer 2006, Infrasound events detected with the Southern California Seismic Network, GRL, 33, L19803, doi: 10.1029/2006GL026951.
- Cochran, E.S., Y.-G. Li, J.E. Vidale 2006, Anisotropy in the shallow crust observed around the San Andreas Fault before and after the 2004 M6 Parkfield earthquake, BSSA, 96, S364-S375.
- Li, Y.-G., P. Chen, E.S. Cochran, J.E. Vidale, and T. Burdette 2006, Seismic evidence for rock damage and healing on the San Andreas fault associated with the 2004 M6 Parkfield Earthquake, BSSA, v. 96 p. S349-S363
- Li, Y.G., J.E. Vidale, and E.S. Cochran 2004, Low-velocity damaged structure of the San Andreas Fault at Parkfield from fault-zone trapped waves, Geophys. Res. Lett., v. 31.
- Cochran, E.S., J.E. Vidale, and S. Tanaka 2004, Earth tides can trigger shallow thrust fault earthquakes, Science, 306, p. 1164-6.
- Li, Y.-G., J.E. Vidale, S.M. Day, D.D. Oglesby, and E.S. Cochran, 2003 , Postseismic fault healing on the rupture zone of the 1999 M 7.1 Hector Mine, California, earthquake, Bull.Seis.Soc.Am., v. 93.
- Li, Y.-G., J.E. Vidale, D.D. Oglesby, S.M. Day, and E.S. Cochran 2003, Multiple-fault rupture of the M7.1 Hector Mine, California, earthquake from fault zone trapped waves, J. Geophys. Res., v. 108, p. 2165.
- Cochran, E.S., J.E. Vidale, and Y.G. Li 2003, Near-fault anisotropy following the Hector Mine earthquake, J. Geophys. Res., v. 108, p. 2436.
- Alex, C.M., L. Gurrola, E.S. Cochran, T. Tyler, C. Nicholson, and R.J. Archuleta, Seismic hazards to the University of California Campus at Santa Barbara. Seism. Res. Lett., 68, 305, 1997.
- Cochran, E.S., and R.J. Archuleta, Site amplification in the Santa Ynez Valley, Southern California Academy of Sciences Program and Abstracts, May 1996.