Some observations regarding depth of exploration in D.C. electrical methods

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

“…1. In locations with good access paths and/or roads, the current cables were extended up to 1000 m in order to ensure that depths above 200 m were comfortably sampled assuming that penetration depth varies between 0.25AB and 0.5AB (Roy and Elliot, 1981;Singh, 2005). Corresponding receiving (potential) electrode separation (MN) varied from a minimum of 0.5 m at AB = 2 m to a maximum of 50 m at AB = 1000 m. At all the electrode positions, great care was taken to ensure that the separation between the potential electrodes did not exceed one fifth of the separation of the current electrodes (Gowd, 2004).…”

Geoelectrohydraulic parameters of shallow sandy aquifer in Itu, Akwa Ibom State (Nigeria) using geoelectric and hydrogeological measurements

“…Using SAS 4000 ABEM Terrameter employing Schlumberger electrode configuration, the apparent resistances were measured. The current cables were extended up to 1000 m in order to ensure that depths above 200 m were comfortably sampled assuming that penetration depth varies between 0.25 and 0.5 of the current electrode separation (AB) (Roy and Elliot, 1981;Singh, 2005). Corresponding receiving (potential) electrode separation (MN) varied from a minimum of 0.5 m at AB = 2 m to a maximum of 50 m at AB = 1000 m. At all the electrode positions, care was taken to ensure that the separation between the potential electrodes did not exceed one fifth of the separation of the current electrodes (Gowd, 2004).…”

“…However, with the recent technological innovations in geophysical prospecting methodologies such as the advent of surface nuclear magnetic resonance (SNMR) technique and spectral induced polarisation (SIP) and improvements in analytical and interpretational tools used for the analyses and interpretation of classical geophysical data, the prospects of off-setting these ambiguities by direct information extraction have increased significantly (Yaramanci et al, 1999;Sailhac et al, 2004;Vereecken et al, 2004;Jouniaux et al, 2009;Kirsch, 2009;Daigle and Dugan, 2011;Günther and Müller-Petke, 2012;Ikard et al, 2012;Jouniaux and Ishido, 2012;Kulessa et al, 2012). The applications of SNMR to groundwater investigation have been a very revolutionary innovation as it has been found to be useful in various investigative aspects including direct detection, identification and quantification of the free-water content in a saturated formation and estimation of the major geoelectrohydraulic parameters (Roy and Elliot, 1981). Improvements in information extraction procedures from coupled geophysical data have also led to tremendous reduction in the usual uncertainties associated with the normal conversion of geophysical information to hydrological properties and other associated deductions (Hinnell et al, 2010).…”

Assessment of Economically Accessible Groundwater Reserve and Its Protective Capacity in Eastern Obolo Local Government Area of Akwa Ibom State, Nigeria, Using Electrical Resistivity Method

“…This confined the VES points to the locations shown in Figure 1. In locations with good access paths and/or roads, the current cables were extended up to 1000 m in order to ensure that depths above 200 m were comfortably sampled assuming that penetration depth varies between 0.25 and 0.5 [21,22]. Corresponding receiving (potential) electrode separation ( ) varied from a minimum of 0.5 m at = 2 m to a maximum of 50 m at = 1000 m. At all the electrode positions, great care was taken to ensure that the separation between the potential electrodes did not exceed one-fifth of the separation of the current electrodes [23].…”