RECENT AEM CASE STUDY EXAMPLES USING A FULL WAVEFORM TIME-DOMAIN SYSTEM FOR NEAR-SURFACE APPLICATIONS

Abstract

A new time-domain design implementation for the VTEM helicopter time-domain EM system, known as “Full-waveform” VTEM, addresses the early time issues that have been limiting its shallow mapping capability for near-surface applications. The Full-waveform design implementation consists of a combination of a) streamed half-cycle recording of transmitter and receiver waveform data, as well as b) continuous system calibration corrections, b) parasitic-noise and transmitter-drift corrections, and d) ideal-waveform-deconvolution corrections that are applied in a separate post-processing step. This leads to an improvement in usable early time data from ~100usec in standard VTEM systems to ~20usec for Full waveform VTEM. This results in a vastly improved near-surface hydrogeologic characterization. The Full-waveform system and theory were previously described by Legault et al. (2012). This paper presents VTEM case-study examples with emphasis on near-surface applications. Introduction