SEGJ Technical Conference

An example of resistivity mapping around a river embankment by the broadband electromagnetic sensor GEM-2

Abstract We did electromagnetic method that used the GEM-2 in order to research the trace of a past flood as part of the evaluation of safety of river embankment in an area of around the Chikuma River embankment Ainoshima, Suzaka, Nagano Prefecture. By specifying a wet area after comparing with two contour map of resistivity in rainy and dry season, it is efficient measures in clarification of cause of the embankment water leak and extraction of section where improvement is necessary. The 2D resistivity-depth section is obtained by 1D inversion of about 6,000 sample data of multi-frequency that acquired in measurement district of about 300 hectares. After that, make pseudo 3D model for contour map of resistivity. We obtain the useful data for evaluation of safety of river embankment.