社団法人　物理探査学会
第123回(平成22年度秋季)学術講演会

講演要旨(和文) 講演要旨(英文) In the dipole-dipole electrical resistivity survey, we often measure negative apparent resistivity values, which have been regarded as noises or measurement errors. However, some numerical tests showed that the negative apparent resistivity values could be obtained in the area where specific subsurface geological structures, such as a U-shaped or a crescent-shaped anomalous body, are buried near the surface. Nevertheless, we are still not convinced that the negative apparent resistivity can be generated by the geological structures. In order to verify the phenomena, we carry out a scale modeling using a water tank and a graphite board. The graphite board is used to simulate the U-shaped and the crescent-shaped anomalous body. The scale modeling demonstrates that the negative apparent resistivity values can be measured where the U-shaped or the crescent-shaped structure is located near the surface.