Electrical resistivity tomography reveals groundwater potential around Lonar Crater, India, in semi-arid basalt terrain

Lonar Crater in Maharashtra, India, is a well-preserved impact crater in Deccan Trap basalt, where groundwater potential is expected to vary sharply because storage and flow are controlled by weathering, vesicular horizons, fractures, and ejecta-derived cover. To identify groundwater-favourable zones, nine 2-D electrical resistivity tomography (ERT) profiles were acquired around the crater rim using an ABEM multi-electrode system with 48 electrodes at 10 m spacing, producing profile lengths of about 470–480 m. The inverted sections show pronounced spatial heterogeneity in shallow subsurface resistivity. The eastern and northeastern sectors, particularly profiles P3 and P7, exhibit laterally persistent low to moderate resistivity corridors (P3: 19.9–229 Ohm m; P7: 13.6–120 Ohm m) that are interpreted as potential water-bearing fractured and weathered basalt. In the southern sector, profiles P1, P2, P8, and P9 contain shallow conductive zones linked to weathered basalt, vesicular units, and ejecta, suggesting shallow unconfined to perched groundwater-favourable conditions; P8, for example, shows a conductive layer extending to about 15–20 m depth. In contrast, the western and northern sectors (P4-P6) are dominated by thick resistive basalt with only thin or discontinuous conductive patches, implying limited storage potential. Because resistivity interpretation is non-unique, the conductive zones are treated as indicative targets rather than direct proof of aquifer productivity. The study provides a field-based framework for groundwater targeting and recharge planning in semi-arid hard-rock basalt terrain.