Groundwater Geophysics

Geophysical investigation of Obot Ekpo Landslide site, Cross River State, Nigeria

“…The second layer was observed to be characterised by an average seismic P-wave velocity of 1820.8 and 1769.9 m/s respectively for the first and second stations. The underlying clayey materials created a blind zone that did not allow first break signals from this layer and other deeper layers to be observed on the surface (Šumanovac and Weisser, 2001;Rabbel, 2009). This significantly limited the penetration depth of the seismic signals.…”

“…Finally, in geologic environments where insulating substances such as certain forms of chlorinated dense non-aqueous phase liquids (DNAPLs) contaminate the saturated aquifer, resistivity estimated from Archie's law will be unrealisable (Vinegar and Waxman, 1984;Worthington, 1993;Tait et al, 2004;Rivett and Clark, 2007;Chambers et al, 2011). Another subsurface condition where Archie's law will also be non-applicable includes partly saturated aquifers (Alger, 1966;Huntley, 1987;Martys, 1999;Börner, 2009). Under such terrains and subsurface conditions, models that incorporate the effects of these extraneous influences on observed resistivity have been developed.…”

Geohydrodynamic properties of hydrogeological units in parts of Niger Delta, southern Nigeria

“…Generally, the electrical resistivity method involves injecting electrical current into the ground through a pair of electrodes (called current electrodes) and monitoring the potential difference created by the passage of the electrical current through the earth materials using another pair of electrodes technically called potential electrodes. Details of this can be found in Keller and Frischkencht (1966), Telford et al (1990), Zhdanov and Keller (1994) and George et al (2014). Many electrode configurations and field procedures that can be used to perform geoelectrical investigations are available (Telford et al, 1990).…”

“…In sediments of intergranular porosity, pore geometry factor of approximately unity is realisable (Keller and Frischkencht, 1966). For consolidated sandstones, Parkhomento (1967) obtained a pore geometry factor of 0.4.…”

“…In documented materials the general range of cementation factor spans between unity in loose and fractured rocks (Aguilera, 1976;Jorgensen, 1988) and 5.12 for dense, hard and well indurated formations (Wyble, 1958). Specifically, the estimated cementation factors for various petrofacies are 1.09, 1.3, 1.3-1.6, 1.5-2.3, 1.8-3.0 and 1.8-4.2, for porous dolomites, glass spheres, homogeneous clean sands, heterogeneous sediments, compacted sandstones and limestones and argillaceous sandstones and siltstones respectively (Kirsch, 2009;Fadhil et al, 2013).…”