鹿野・吉岡断層周辺におけるガンマー線測定 (I)

Abstract

Intensity of γ-ray has been observed for the purpose of investigating its relationship to earth-quake occurrence since June, 1981. Five regions each of which contains several observation pointshave been set up along two active faults, Shikano and Yoshioka, which ruptured at the time of theTottori earthquake, 1943 (M=7.4). The observation has been done at each point once a month, while some test observations of γ-ray were made at and near the Tottori Microearthquake Obser-vatory, in order to examine daily variation of γ-ray intensity and its correlations to meteorologicalelements and others.The intensity of γ-ray is the largest in Hosomi region which is in hilly area and along the Shikanofault. Observations just on these two faults seem to show somewhat higher intensities than thoseof other points, or to show large dispursion. Intensities measured on Aug. 3, 1981 were the largestin the whole observation period at all points, although the reason is not clear yet.Seismic activity, especially along the Shikano and Yoshioka faults, was examined in somedetail in the period of the present observation, but more investigations are needed in order to discussabout the relations between γ-ray intensity and seismic activity.