Understanding the landslide mechanism and elucidating the geological structure and groundwater flow system is important for effective landslide countermeasures. However, there is clear limitation in the ground survey and geological survey by limited boring. For this reason, the authors conducted a survey using geophysical exploration in addition to the ground survey and boring survey, as an example of the Arasegawa landslide of the dip-slope which was completed the temporary countermeasures in 2000, but recently landslide activities were seen.
The authors gave four interpretations as follows, 1) discontinuity of the stratum corresponding to the observed and the estimated faults ascertained by the ground survey was confirmed by the boring survey. 2) From the distribution of geophysical properties by geophysical exploration, it was possible to spatially estimate the fault and the distribution of the groundwater regulated by the fault. Furthermore, 3) These faults regulating groundwater flow in the landslide area were presumed to reflect the stress field at the time of formation of the ore at the former Ani mine. 4) These results show the effectiveness of joint use of geophysical exploration and can be used for the design of landslide countermeasures.