H. E Bass, E. T Herrin, P. Golden, R. Woodward, D. Drob, M. A H Hedlin, C. De Groot-Hedlin, K. Walker, M. Garces , C. Szuberla and R. Whitaker The University of Mississippi NCPA, 1 Coliseum Drive, University, MS 38677, USA Southern Methodist University, P. O. Box 750395, Dallas, TX 75275, USA Incorporated Research Institutions for Seismology, 1200 New York Avenue, NW, Suite 800, Washington, DC 20005, USA Naval Research Laboratory, Space Science Division, 4555 Overlook Avenue, Washington, DC 20375, USA University of San Diego California, Scripps Institute of Oceanography, 9500 Gilman Drive, La Jolla, CA 92093, USA Infrasound Laboratory, University of Hawaii, 73-4460 Queen Kaahumanu Highway #119, Kailua-Kona, HI 96740, USA University of Alaska, 903 Koyukuk Drive, Fairbanks, AK 99775, USA Los Alamos National Laboratory, EES-2 MS J577, Los Alamos, NM 87545, USA