1. Berkeley Seismological Laboratory, University of California, Berkeley, 209 McCone Hall, Berkeley, California 94720 U.S.A., kongqk@berkeley.edu
2. Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545 U.S.A.
3. Seismological Laboratory, California Institute of Technology, Pasadena, California 91125 U.S.A.
4. Scripps Institution of Oceanography, University of California San Diego, 9500 Gilman Drive, La Jolla, California 92093‐0238 U.S.A.
5. Department of Earth and Planetary Sciences, Harvard University, Cambridge, Massachusetts 02138 U.S.A.