Shallow groundwater exploration in basalt-covered areas using electrical resistivity tomography: A case study from Helong, China

Groundwater in basalt-covered areas primarily occurs within pore zones, cooling contraction fractures, primary joints, tectonic fractures, and weathered layers, resulting in a highly heterogeneous and discontinuous distribution pattern of the aquifers. This work investigates the groundwater system in the Changbai Mountain basalt region using electrical resistivity tomography (ERT). The study area is located in Baili Village, Longcheng Town, Helong City, Jilin Province, where three parallel survey lines of ERT were deployed. The subsurface electrical model of the study area was obtained using a smooth-constrained least-squares inversion method. The results revealed the presence of a localized shallow aquifer and a regionally developed fault zone. The regional fault zone plays a dominant role in controlling shallow groundwater migration and serves as a pathway for groundwater accumulation. The findings demonstrate that ERT is an effective tool for revealing the spatial distribution patterns of discrete groundwater in basalt-covered areas.