Faculty of International Resource Sciences, Akita University, 1-1 Tegata-gakuen-cho, Akita010-0852, Japan;
Sakurajima Volcano Research Center, Disaster Prevention Research Institute, Kyoto University,1722-19 Sakurajima, Yokoyama, Kagoshima 891-1419, Japan;
福建省地震局,福州350003;