[M-IS22] Electromagnetic phenomena associated with seismic and volcanic activities

[MIS22-04] Reinvestigation of correlation between groundwater anomalies and earthquakes carried out by an amateur network in Japan

*Yoshiaki Orihara¹, Masashi Kamogawa², Toshiyasu Nagao¹ (1.Institute of Oceanic Research and Development, Tokai University, 2.Dpt. of Phys., Tokyo Gakugei Univ.)

Keywords:the catfish club, earthquake prediction, groundwater, statistical evaluation

An amateur volunteer group for an earthquake prediction, “the catfish club”, had monitored groundwater levels and the temperature of thermal water to detect earthquake precursor signals since 1976. More than 200 participants in Kanagawa, Tokyo, Shizuoka, and some prefectures monitored them. Their sampled data are sent to the office of the catfish club, and the summarized reports were published every month. Oki and Hiraga (1988) reported the probably predicted events such as the 1978 Izu-Ohshima kinkai earthquake (M 7.0) and the 1978 Miyagiken-Oki earthquake (M 7.4). In this study, we statistically evaluate the anomaly appearance rate, the earthquake occurrence rate, and the probability gain using the data from 1977 to 1987.



Acknowledgment: This study was supported by the Earthquake Research Institute The University of Tokyo Joint Usage/Research Program.