High Spatial Resolution of the Resistivity Structure Revealed by a Dense Network MTMeasurement: a Case Study in the Minamikayabe Area, Hokkaido, Japan

Abstract

In 1988 we carried out a case study survey at Minamikayabe in the southern part of Hokkaido, Japan. This area is particularly interesting because of its geothermal potential. Seven control wells had been drilled prior to our operation, and also some other information has been available other survey methods such as gravity, geology, geochemistry, DC resistivity and heat flow. Hence the area is an site for a study of effectivenessof the MTmethod. Analyses of data derived network MT measurements, which we undertook in the present case study, clearly show that dense network measurements could resolve a spatially fine resistivity structure. In order to attain a high spatial resolution of subsurface resistivity structure in a geothermal or a volcanic area, where the subsurface structure is extremely complicated,we show that a dense network MTmeasurement is indispensable.