UBC-GIF has finished 3D modeling of resistivity gradient survey data with EH3Dinv code. EH3Dinv is a computing code developed at UBC − GIF for inverting controlled source frequency-domain EM data to recover a 3D electrical conductivity (Inversion of 3D electromagnetic data in frequency and time domain using an inexact all-at-once approach. Eldad Haber, Uri M. Ascher, and Douglas W. Oldenburg. GEOPHYSICS, VOL. 69, NO. 5, 2004; P. 1216–1228).
The ERA’s technology, in brief, is “cross-disciplinary” – between frequency-domain and direct current (DC) concepts. The technology provides high resistivity resolution by grounded, non-contact and/or combined modes of electrical field measurements at 1.22-2500Hz. In comparison with DC method ERA equipment is several times more sensitive and in comparison with frequency-domain is defined as high-resolution.
The ERA’s technology of resistivity method exposes the best sensitive to subsurfce resistivity variations as well as a simplicity in theory and in field operations.
The non-contact measurements of electric field has been developed generally in Russia since 60-s – in 1963 for non-contact electrical profiling (B.G.Sapozhnikov), with 1981 – for geoelectrical sounding (A.S.Nahabtcev and A.I.Jabluchansky).
Now the idea has realized on the modern electronic and engineering basis in ERA equipment – transmitter, receiver, special antennas, “active” electrodes, ERA-MULTIMAX imaging system with “active” contacts. The equipment provides wide broad resistivity studies with very high resistivity resolution.
The main applications – ground water, weak alteration processes, archeology, civil engineering, mineral exploration in any surface conditions in any electromagnetic noise including intown operations.