ON INDUCED ELECTRICAL POLARIZATION AND GROUNDWATER

Clay horizons and other clay-bearing unconsolidated sediments are potential sources of induced-polarization anomalies. If such anomalies may be detected above system noise, the induced-polarization method may be of value for in-situ classification of unconsolidated sediments encountered in hydrological projects. One such project exists in Santa Clara County where near-surface unconsolidated sediments are frequently considered as potential recharge areas. Of four areas surveyed with induced-polarization apparatus in Santa Clara County, only two yielded significant frequency-effect anomalies, and in each of these two the frequency effects were of the order of 3 percent. These anomalous frequency effects may be related to clayey gravels. The dipole-dipole array, with spreads of 10 ft and 20 ft, was typically used in the study. © 1968 Society of Exploration Geophysicists.