zones alligned in the southwest bedrock. (ρ>700Ω-m) – northeast directions and occupy a small area in the The first layer is the Topsoil. Its resistivity north western part of the study area. The medium values generally range from 320 5500 ohm-m – to high apparent resistivity zones suggest and its thickness varies from 0.8 2.2m. It is made – bedrock while the low apparent resistivity up of sandy and clayey materials which may be zones are indicative of relatively deep bedrock, indurated in some cases.The second layer is the weathered layer and deep-seated fractures. weathered rock material. The resistivity value Typical depth sounding curves obtained for the range from 300 600 ohm-m and the thickness – area are H, KH, QH, HKH, KQH, KHKH and varies from 2 20m. The layer is composed of – QHKH. A summary of the VES interpretation sandy clay and clayey sand. results are in Table 1. Three geoelectric sections The third layer is the hard fresh rock (boulders). were constructed across the study area (Figs. 6, 7 The resistivity values range from > 1500 ohm-m and 8). These are along the line of section A and its thickness varies from 2 42m. It is – A”, – which runs east west, and sections B and C composed of fresh rock material in boulder forms. – – B” in the north south directions (Fig. The partly weathered rock is the fourth layer with – C” running – 4). The three geoelectric sections delineated six the resistivity value ranging from 600 to 1000 subsurface geoelectric units. These are topsoil, ohm-m and its thickness varying from 5 22m. – weathered rock material, hard fresh rock The layer is made up of partly-weathered granitic (boulders), partly-weathered rocks, rocks. fractured/highly weathered rock material and fresh Figure 3: Apparent Resistivity Distribution for HP of ɑ=20m.
(ρ>700Ω-m) zones alligned in the southwest – northeast directions and occupy a small area in the north western part of the study area. The medium to high apparent resistivity zones suggest bedrock while the low apparent resistivity zones are indicative of relatively deep bedrock, weathered layer and deep-seated fractures. Typical depth sounding curves obtained for the area are H, KH, QH, HKH, KQH, KHKH and QHKH. A summary of the VES interpretation results are in Table 1. Three geoelectric sections were constructed across the study area (Figs. 6, 7 and 8). These are along the line of section A – A”, which runs east – west, and sections B – B” and C – C” running in the north – south directions (Fig. 4). The three geoelectric sections delineated six subsurface geoelectric units. These are topsoil, weathered rock material, hard fresh rock (boulders), partly-weathered rocks, fractured/highly weathered rock material and fresh bedrock. The first layer is the Topsoil. Its resistivity values generally range from 320 – 5500 ohm-m and its thickness varies from 0.8 – 2.2m. It is made up of sandy and clayey materials which may be indurated in some cases.The second layer is the weathered rock material. The resistivity value range from 300 – 600 ohm-m and the thickness varies from 2 – 20m. The layer is composed of sandy clay and clayey sand. The third layer is the hard fresh rock (boulders). The resistivity values range from > 1500 ohm-m and its thickness varies from 2 – 42m. It is composed of fresh rock material in boulder forms. The partly weathered rock is the fourth layer with the resistivity value ranging from 600 to 1000 ohm-m and its thickness varying from 5 – 22m. The layer is made up of partly-weathered granitic rocks. Figure 3: Apparent Resistivity Distribution for HP of ɑ=20m.