HR: 0800h
AN: S41B-0989 [Abstracts]
TI: Prediction of Triggered Slip and Aftershocks in the Salton Trough: Which
is Better, Dynamic or Static Coulomb Failure Stresses?
AU: * Clark, J
EM: malichan99@hotmail.com
AF: Dept. of Geological Sciences, San Diego State University, 5500 Campanile Dr., MC-1020, San Diego, CA
92182
United States
AU: Verdugo, D
EM: danie143@aol.com
AF: Dept. of Geological Sciences, San Diego State University, 5500 Campanile Dr., MC-1020, San Diego, CA
92182
United States
AU: Olsen, K
EM: kbolsen@sciences.sdsu.edu
AF: Dept. of Geological Sciences, San Diego State University, 5500 Campanile Dr., MC-1020, San Diego, CA
92182
United States
AU: Mellors, R
EM: rmellors@geology.sdsu.edu
AF: Dept. of Geological Sciences, San Diego State University, 5500 Campanile Dr., MC-1020, San Diego, CA
92182
United States
AB:
We have modeled static (CFS) and dynamic (dCFS(t)) Coulomb failure stresses within a 140 km by 140 km area in southern
California for four recent historical M>6 earthquakes (1968 Borrego Valley, 1979 Imperial Valley, 1987 Elmore Ranch and
1987 Superstition Hills events) using a fourth-order finite-difference method and a layered crustal model. The dynamic
stresses, quantified as the peak values of the dCFS(t), are computed using slip models estimated from measured surface
offsets and extended down to the bottom of the fault. The CFS and dCFS(t) are correlated with aseismic slip recorded on
nearby structures in the Salton Trough, as well as aftershocks from the four events. Our simple models suggest that, compared
to static Coulomb failure stress patterns, the patterns of peak dCFS(t) show a higher correlation with triggered slip along
nearby faults, and for some of the events, with the location of aftershocks that occurred up to four years after the events.
This finding is due to the rupture propagation effects, particularly directivity, included in the dCFS(t) (e.g., Kilb et al,
2000), but omitted for the CFS. Future studies should include a 3D crustal model and refined rupture propagation in the
dCFS(t) computation.
DE: 1209 Tectonic deformation (6924)
DE: 7209 Earthquake dynamics (1242)
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
SC: Seismology [S]
MN: Fall Meeting 2005