Three-Dimensional Inversion Of Ip Data From The Inel Cold Test Pit

The Cold Test Pit (CTP) has been carefully constructed to simulate stored hazardous<br>waste occurrences at the Idaho National Laboratory (INEL). An induced polarization (IP)<br>survey of the CTP shows a very strong polarization anomaly and a modest resistivity<br>response associated with the simulated waste.<br>The data have been interpreted using a three-dimensional (3-D) inversion algorithm<br>based on the simultaneous iterative reconstruction technique (SIRT) and finite difference<br>forward modeling to form a subsurface model of complex resistivity.<br>The edges of the waste zone are well resolved. Limited depth extent is recognized,<br>though the bottom of the waste appears too deep. The intrinsic polarizability of the waste<br>material has been estimated by means of a forward modeling experiment.<br>The IP method holds promise as a technique to distinguish buried waste from pockets of<br>conductive soil material, such as are present at the CTP.