Abstract

Geophysical investigations were carried out using Resistivity, VLF and Magnetic methods to delineate the subsurface structure around the hot springs of Tarabalo in central Odisha. The present investigation aimed to delineate the shallow subsurface configuration of the study area to understand the probable fracture network and weak zones feeding the cluster of hot springs spread over the area. The study deciphers highly fractured three layered subsurface configurations with depth ranges of 1-50 m, 50-70 m and beyond 70 m consisting of different composition and physical properties. Resistivity study reveals a conducting channel continuing beyond 70 m depth which is also in accordance with the VLF results. The magnetic highs in the region surrounding the hot spring may be due to the high iron content of Khondalite and Charnockite group of rocks which are overlaid by thick quaternary sediments. Thus, it can be inferred from this preliminary geophysical investigation that the hot springs in the study area are feeded by the heat source at a depth greater than ~70 m through some conducting channels and fracture network. A high resolution Gravity, magnetic and deep resistivity study is indispensable for a detailed understanding of the subsurface geothermal system.