Borehole-to-Surface ERT Inversion

A005 BOREHOLE-TO-SURFACE ERT INVERSION Introduction 1 Increasing use is being made of cross-hole ERT to scan between two or more boreholes (Daily and Owen 1991; Daily and Ramirez 2000). However cross-hole tomography cannot be used successfully if the boreholes are too widely spaced. In such cases combined use of surface and single-hole electrodes (Bevc and Morrison 1991) or even single-hole ERT measurements can be considered (Tsourlos et al. 2003). Although the cross-hole ERT case has been studied extensively only limited information about the borehole-to-surface ERT measuring mode exists in the literature. In this work we examine the case of inverting