RMZ – MATERIALI IN GEOOKOLJE

The groundwater potential evaluation at industrial estate Ogbomoso, ...(Evwaraye & Mgbana, 1993) as:V = EL (3)where E is the electric field strengthwith dimension of volt per meter(V/m).If the current electrode is taken to penetratea small hemisphere of radius r,then ρL the area of the hemisphere becomesρLρL A2πr 2 .AASubstituting22πfor E and integrating2rEquation2 πr2πr3 gives:∆V=∆V=∆V= ∫ E.∫∫E.dr.E.dr.dr.(Duffin, 1979) (4)IρρL ∆V= Iρor ∆VI=ρ(5)∆V=2πrA 2πr2πrand ρ = ∆V.2πr2(6)2ρπ=r ρ = ∆V.2πr∆V.2πrSince the ∆earth V is not homogeneous,∆V= ρ ∆VEquation ρ ∆∫a E=. dr.. Ga= V 6 is used to define an apparentresistivity ρ aρa= . GI . GIwhich is the resistivityIρthe ∆Vearth = would ABhave 2 if MN it were 2π (( ABhomogeneous2)− MN ( 2))2π(((GrantAB r(()) (& MN −West, (π − ) ) 1965). ) )G = 2 2 EquationGG6= 2can 2be written MN22 in a general formρ = ∆V.2πr2( MN )as: MN 2(2( )2 )22∆Vρa= ρ1> . Gρ2< ρ3ρ (7)1>ρ1> ρIρ2< ρ32< ρ3where ρ G is a geometrical factor fixed1< ABρ22>ρ MN3< ρ42for ρ a ρ given π ((1< ρ2electrode ) > − ρ (3< ρ4configuration.) )G1=< ρ2> 2ρ3< ρ42MN n−1n−1The Schlumberger 2( n−)1electrode n−1configurationhas been used in this hstudy. In thishin−12n−1hi∑ h∑ hiρihiρiiρ1 i ∑∑ρti=1 i=1 ρiλ = ρt= i=i=1 ρiarrangement, λ = t=n−1icurrent 1 is i=ρ = =injected ρn−1i 2λlinto the1> ρ2 ρ3< ρ4KRMZ-M&G T = K 2012, × R59T= Kσ× RT K= × RT = K× R TT = × Rρ n−1 n−1T= Kσ× R TρT hiρ h ρIρ∆V=2πr371ρ = ∆V.2πranother pair of electrodes. The geometricalfactor ∆Vρ for the schlumberger electrodeconfiguration I is givena= . Gby:AB 2 MN 2π (( ) − ( ) )G = 2 2(8)MN2( )2where AB is the distance between twocurrent ρ1> ρ2electrodes, < ρ3and MN is the distancebetween two potential difference.ρ < ρ > ρ