[1] Univ Grenoble 1, CNRS, ISTerre, F-38041 Grenoble, France
[2] Univ Calif Berkeley, Dept Civil & Environm Engn, Berkeley, CA 94720 USA
[3] Univ Nevada, Nevada Seismol Lab, Reno, NV 89557 USA
[4] Univ Nevada, Dept Geol Sci & Engn, Reno, NV 89557 USA