2-D Earth Resistivity Imaging for Subsurface Characterization in Srinagar, Garhwal Himalaya

Abstract

Resistivity imaging technique is a geo-electrical method used to image the subsurface, water bearing zone, bedrock and layer thickness. The 2-D resistivity imaging method is a non-invasive technique which provides reliable picture of the subsurface at shallow depths. The application of this method for site investigation is becoming common nowadays. In the field of civil engineering site investigations, it is frequently used along with seismic refraction survey. In the present study, 2D electrical resistivity imaging has been used as a tool for subsurface geological characterization and delineation of sub-surface strata in Srinagar, Garhwal Himalaya, India. The aim of this survey was to map the shallow subsurface and geophysical properties i.e. resistivity and layer thickness. The survey was carried out on both sides of the river Alaknanda which flows through the city using ABEM Terrameter LS equipment. The data was processed using RES2DINV software. Three boreholes were also drilled in the area of study to evaluate the results obtained from the imaging survey. The results of the models show that the study area is predominantly of sand formation however, some clayey sand is also present in some areas as indicated by both the imaging and the borehole drilled.