|
| | 講演要旨(英文) | | Loop-loop electromagnetic (EM) measurements over certain geological terrain can yield negative apparent conductivity response, which is due mainly to 2-D and 3-D structural effects. Qualitative interpretation of such data sets can be misleading especially when an anisotropic effect on the local EM signature exists. If care is not taken to collect data at various coil alignment azimuths, an interpreter may be misled to think that the subsurface geoelectrical structure is low conductive whilst the opposite is true. In this work, we present 3-D forward modeling results of two case studies in Akita Prefecture, a black-ore (Kuroko) deposit in Odate city and a dacite dike intrusive complex in Daisen city respectively. The geoelectrical characteristics of the earth beneath the negative apparent conductivity responses were further inspected by vertical electrical soundings (VES) and DC resistivity surveys and shown to have a correlation between negative apparent conductivity and low resistivity. |
|
|
|
| |
|