Affiliation: | Lawrence Livermore National Laboratory, Geophysics and Global Security Division, PO Box 808, Livermore, CA;94551-9900, USA. E-mail: , San Diego State University, Department of Geological Sciences, San Diego, CA, USA,;King Saud University, Geophysical Observatory, Riyadh, Kingdom of Saudi Arabia,;University of California, Santa Cruz, Institute of Tectonics, Santa Cruz, CA, USA |