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

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