1. 1U.S. Geological Survey, Geologic Hazards Science Center, Golden, Colorado, U.S.A.
2. 2U.S. Geological Survey, Earthquake Hazards Program, Golden, Colorado, U.S.A.
3. 3U.S. Geological Survey, National Civil Applications Center, Lakewood, Colorado, U.S.A.
4. 4Department of Geological Sciences, University of Nevada Reno, Reno, Nevada, U.S.A.
5. 5Department of Geological Sciences, California State University Fullerton, Fullerton, California, U.S.A.