Comparison between SVD-Based and Automatic Geophysical Inversion for Schlumberger VES Data: A Case Study from Konkan Coast, Maharashtra

Abstract

A comparison is made between the resistivity modeling results obtained from Singular value decomposition (SVD) based geophysical inversion method and a semi-automated inversion scheme to assess the robustness of the SVD method. A total of 30 vertical electrical soundings (VES) data were collected from the hard-rock area of Konkan coastal Maharashtra and modeled using the new method. The results are interpreted so as to identify the coastal aquifers contaminated with saline water in the study area. The SVD- based inversion results suggest a very high resistivity formation in the north-eastern part of the area, presumably due to the presence of laterites at the top, followed by hard and compact basalts beneath. In the south-eastern part of the study area, a very high resistivity zone is evident, due to the presence of laterites and basalts. A very high conductive zone is revealed in the south- western part near the coast signifying extensive influence of saline water ingress, which diminishes from south-west to north-eastern part of the region. It is also seen that the results obtained from the SVD-based algorithm is superior to the conventional inversion scheme.