2-D Interpretation of Minamikayabe MT Data Set by the Controlled Random Search Technique

Within the MT-DIW3 project of the comparison of various MT interpretation techniques, the controlled random search procedure was applied to the 2-D interpretation of the MT data from the Minamikayabe MT polygon in Japan. Three NE-SW profiles together with one perpendicular profile were 2-D modelled, simultaneously for both polarizations of the MT field. Although the 2-D approximation seems to be rather far from the real resistivity conditions, we could obtain relatively consistent interpretation results particularly for data within the short period range, up to 1 s. Better fit was achieved for apparent resistivities than for phases. For all NE-SW profiles, a near-surface conductive body is indicated below the central part of the polygon. At both sides of this body two deeper conductive zones are obvious. As for the perpendicular profile kb*s06, a large conductive zone is required below the SE margin of the profile.