Affiliation: | Earthquake Research Institute, University of Tokyo, Yayoi 1-1-1,;Bunkyo-ku, Tokyo 113-0032, Japan. E-mail: Seismological Laboratory, University of California at Berkeley 215;McCone Hall, Berkeley, CA 94720-4760, USA. E-mail: Institute of Space Technology and Aeronautics, Japan Aerospace Exploration Agency, Jindaiji Higashi-machi 7-44-1,;Chofu-shi, Tokyo 182-8522, Japan. E-mail: |