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.

Evaluation of backfilling effectiveness plays a crucial role in the geological environment management and restoration of abandoned open-pit quarries, providing a scientific basis for subsequent greening efforts. Backfill soil, predominantly composed of silty clay, demonstrates high water retention capacity and elevated moisture content, leading to a pronounced resistivity contrast with the bedrock exposed by quarrying activities. To investigate the distribution of backfill soil subsurface and assess backfilling effectiveness in the study area, this study conducted a comprehensive geophysical investigation utilizing the high-density electrical resistivity tomography (ERT). A total of 19 ERT survey lines were deployed across three distinct areas in Liuyao Village, Huaibei City, Anhui Province, China. The inversion results, derived from both two-dimensional (2D) and three-dimensional (3D), reveal distinct electrical properties of the subsurface materials: the backfill soil layer shows low resistivity features, the fill stone layer exhibits medium to high resistivity, and the bedrock shows the highest resistivity. The 2D inversion results, from the data measured using the Wenner array effectively capture the spatial distribution and structural features of the backfill soil layer. The findings indicate a gradual east-west thinning of the clay layer within the quarry. Furthermore, the northern pit area exhibits a uniform distribution of backfill soil layer, indicative of effective backfilling operations. In contrast, the southern pit area lacks a well-defined clay layer, suggesting suboptimal backfilling effectiveness.