1. Atmospheric, Earth and Energy Division and Geophysical Monitoring Program, Lawrence Livermore National Laboratory, 7000 East Avenue, L‐046, Livermore, California 94551 U.S.A., rodgers7@llnl.gov
2. Also at Earth and Environmental Sciences Area, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, MS74R316C, Berkeley, California 94720 U.S.A.
3. Also at Berkeley Seismological Laboratory, University of California, Berkeley, 307 McCone Hall #4760, Berkeley, California 94720‐4760 U.S.A.
4. Center of Applied Scientific Computing, Lawrence Livermore National Laboratory, 7000 East Avenue, L‐561, Livermore, California 94551 U.S.A.
5. University of Nevada, 1644 North Virginia Street , Reno MS 0258, Reno, Nevada 89577‐0258 U.S.A.
6. Department of Civil and Enviornmental Engineering, University of California, Berkeley, 455 Davis Hall, Berkeley, California 94720‐1710 U.S.A.