Extracting information from ZTEM data with 2D inversions

Abstract

A 2D Occam inversion algorithm for modeling ZTEM data is described that takes into account topography and EM receiver terrain clearance. The responses of hills and depressions are shown for synthetic models. These results show that hills and depressions produce responses that could be confused with the responses of conductors and resistors, respectively. The analysis of ZTEM data acquired at different flight-line directions at the Forrestania test site, WA, shows great consistency and repeatability of the ZTEM data. 2D inversion results indicate that the derivation of pseudo tipper profiles, perpendicular to the survey flight-line direction, from across-line data contain valuable information, especially where the local strike is not perpendicular to the flight-line direction.