1. Department of Geosciences Virginia Polytechnic Institute and State University Blacksburg Virginia USA
2. Seismological Laboratory California Institute of Technology Pasadena California USA
3. U.S. Geological Survey Menlo Park California USA
4. Nevada Seismological Laboratory University of Nevada, Reno Reno Nevada USA
5. Scripps Institution of Oceanography University of California, San Diego La Jolla California USA
6. Department of Geology Centro de Investigacion Cientifica y de Educacion Superior de Ensenada Ensenada Mexico
7. Instituto de Ingeniería Universidad Autónoma de Baja California Mexicali Mexico