1. Geophysicist, National Earthquake Information Center, U.S. Geological Survey, Golden, CO 80401 (corresponding author).
2. Civil Engineer, National Earthquake Information Center, U.S. Geological Survey, Golden, CO 80401.
3. Geophysicist, National Earthquake Information Center, U.S. Geological Survey, Golden, CO 80401.
4. Physical Scientist, FEMA, Denver, CO 80225.