Delineation of Potential Groundwater Zones Using Shear Wave Velocity in Eastern Deccan Volcanic Province, India

Abstract

A comprehensive study based on Multichannel Analysis of Surface Waves (MASW), a near-surface geophysical technique, was carried out for the first time in the Mandla Lobe of the Eastern Deccan Volcanic Province. The study was conducted to demarcate fractures, which are essential for finding potential groundwater zones in the hard rock region and for the delineation of shallow subsurface geological features in terms of shear wave velocity. The MASW surveys were carried out at different selected locations in the study area to delineate fractures in the basaltic terrain covered with thin weathering and alluvium cover. These basalts are mainly comprised of massive, vesicular and amygdaloidal varieties and interpreted as different basaltic flows of Mandla, Dhuma and Pipardahi formations. The shear wave velocity sections divulge the layered nature of the basalt sequences. In some of the massive flows, there are low-velocity vertical zones that can be deduced to be either vertical columnar joints or fracture zones, and the low-velocity weathered flows can be the good groundwater reservoirs. The shear wave velocities Vs obtained are in the range from 300 to 2500 m/s at different locations, and the thicknesses of flows are varied in the MASW sections. The obtained shear wave data are compared with the borehole data, and the results are well correlated. The study clearly differentiates the variations within basaltic formations, which are interpreted as potential groundwater zones.