Mapping of Conductive Zones for Groundwater Potential Using VLF-EM Method in Akwanga, Nasarawa State Nigeria
Ubaidullah, A.
Aisha A. K
Ayyaninuola O. S.
Tukur R. S.
Abstract
Very low frequency (VLF) electromagnetic measurements were carried out in Akwanga for the mapping of fractured and conductive zoneswith the aim of delineating subsurface structures associated with groundwater occurrence by determining the depth and lateral extent of conductive zones inferred as major aquifers in the study area. A total of twelve (12) profiles were carried out with 10m sample interval along each profile and spread length ranging between 120m and 560m using GEM-19 VLF System.The field data obtained were processed, filtered and interpreted using Karous-Hjelt (K-H) filtered pseudo-section to visualise 2-D conductivity image of the subsurface. The results of the study showed the presence of fracture zones and are prominently oriented in the NE-SW and NW-SE direction. The result also revealed that most of the fractured zones were located at a depth range of 0 up to 60m within the subsurface. The presence of and interconnectivity of the fracture zones show that the study area has good prospects for groundwater. On the basis of the investigation The study therefore recommends the drilling of productive and sustainable boreholes at locations traverse 1, traverse 2, traverse 4, traverse 6, traverse 7 and traverse 10between 150-250 m, 75-175 m, 150-200 m, 120-220 m, 250-300 m and 160-220 m respectively along the profile.
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