Anisotropy of hydraulic conductivity through shallow geophysical surveys

A geophysical investigation, including surface seismic refraction and electrical resistivity methods with radial scanning, was carried out at two test sites of the Apulia region (Italy), in carbonate and evaporite environments characterized by karstic processes. The main aim of the studies was to test the effectiveness of the above mentioned methods to highlight the anisotropy of hydraulic conductivity of the rock masses on the base of accurate surface and subsurface analysis of the karstic features and flow conditions. The electrical resistivity method provided useful indications about the nature of the void filler (water or residual soils) along the fracture and joint families; the seismic refraction method gave, in a fractured and karstified system, information on the loss of material on the base of fractures knowledge of p- waves velocity, density and Poisson ratio of the intact material and of the joint enlargements filler. The radial scanning configurations revealed very useful in giving a well based forecast of karst development directions; the combination of different geophysical techniques allowed reducing uncertainty linked to interpretation of discrete values of physical properties in jointed rock masses and evidencing the anisotropy features.