Affiliation: | Institute of Oil and Gas Problems, Russian Academy of Science, Moscow 119991,;Russia. E-mail: United Institute of Physics of the Earth, Russian Academy of Science, Moscow 123810,;Russia. E-mail: National Research Institute for Earth Science and Disaster Prevention, Tennodai 3-1,;Tsukuba, Ibaraki 305, Japan. E-mail: Research Center for Prediction of Earthquakes and Volcanic Eruptions, Graduate School of Science, Tohoku University, Sendai 980-8578,;Japan. E-mail: |