The Application of Vertical Electrical Sounding (VES) for the hydrogeological and Geophysical Investigations in Kibumba Region, North Kivu, Democratic Republic of Congo (DRC)

A natural and instantaneous geophysical method for groundwater investigation in the volcanic formations of Kibumba Region, North Kivu, Democratic Republic of Congo (DRC) has been developed. A geophysical evaluation using Electrical Resistivity method for groundwater investigation at the study area was carried out which involved the utilization of Vertical Electrical Sounding (VES) technique with Schlumberger array system. The study area is located within the igneous rocks, sedimentary, and metamorphic. The data acquired from twelve (12) VES stations using ABEM terrameter (SAS 1000) was tabulated in a table which shows the resistivity, the thicknesses and the number of layers for each VES station. The data was analysed using computer inversion software called INTERPEX1D, which yield an automatic interpretation of the apparent resistivity. The VES results revealed heterogeneous nature of the subsurface geological sequence. The geological profile sequence in the study area includes the topsoil (clay and fragments rocks and/or boulders formations of basalt), weathered layer (and/or fractured basalt) and fresh basement. The value for topsoil ranges from 10 Ωm to 1500 Ωm with thickness varies from 0.3 m to 10 m. The weathered layer (and/or fractured basalt) resistivity ranges from 100 Ωm to 2000 Ωm and thickness of 3 m to 20 m. The fresh basalt or bedrock basement ranges in value from 30 Ωm to 3000 Ωm with an unknown thickness due to the volcanic formation in the study area. However, the bedrock depth of all the VES stations from the earth’s surface could be ranges from 1 m to 34 m. The results of the VES surveys give an understanding of subsurface electrical properties at the project site.