Abstract
In order to examine the applicability of vertical electrical sounding (YES) to the Ryukyu Limestone distributing area, we have compared the results of VES and borehole data carried out at the catchment area of Sunagawa Subsurface Dam.
VES curves obtained indicate three or four layer models with high resistivity layer lying between low resistivity layers, and this is compatible with borehole data. Estimation of the thicknesses of layers by VES are not sufficiently successful. However, relatively high correlation coefficient with borehole data (0.79) shows that direct reading method is preferable in estimating basement depths to linear filter method.
Resistivity of Ryukyu Limestone is affected by frequency of cracks, degree of secondary clay content and thickness of surface clay layer. Hydrauliconductivity and resistivity of Ryukyu Limestone show positive correlation weakly, however, it is difficult to predict the permeability of Ryukyu Limestone by VES in the region like this.
