活断層における地電位差観測(1)-北陸観測所坑内および牛首断層における観測-

Abstract

Geoelectric phenomena seem to be sensitive to geophysical activities. Active faults are also considered to be sensitive to geophysical conditions of the crust. Therefore, experimental observations of self-potential variations have been carried out on the fault zones.A small-size fault runs throughout the observation vault of the Hokuriku observatory, Disas. Prey. Res. Inst. Of Kyoto Univ..An array observation of self-potential variations has been carried out in the vault.Spatial distribution of self-potential reflects the spatial distribution of underground water in the vault. Leakage current from the railway shows two major directions of its vector. This may concern the relation betWeen locations of trains and transformer substations of the railway.In order to detect the self-potential variations caused by explosion seismic waves, self-potential observations were carried out just on the Ushikubi fault, an active fault in Toyama Pref.. Slite variations of self-potential probably caused by elastic waves were recognized.Array distribution of electrodes is effective to improve the reliability of self-potential observations.