Two-dimensional ERT Modeling to Detect Buried Channels

Abstract

Electrical resistivity tomography is a geophysical method that investigates 2D and 3D subsurface distribution of resistivity, especially in environmental and engineering problems. Most common geoelectrical arrays in 2D tomography are: Wenner Alpha, Wenner- Schlumberger and Dipole- Dipole. Recording the response of a target and the resolution of geoelectrical section are function of array type and survey parameters. This paper has analyzed the ability of these arrays to detect a buried channel. Forward modeling and solving inversion problem have been done by RES2DMOD and RES2DINV programs, respectively. Results show that Dipole-Dipole array is more capable to make a resolved image of the channel. But, its data density, vertical and horizontal resolution and sensitivity are related to its survey parameters such as: dipole length and electrode spacing. So that, to make a resolved image of channel, the electrode spacing must be less and equals to half of channel width, and dipole length must be less and equals to 1.78 times of channel depth.