Electrical properties of basalt: Relation of laboratory to in situ measurements


  • J. F. Hermance,

  • A. Nur,

  • S. Bjornsson


In situ measurements of the electrical resistivity of Icelandic basalts using Schlumberger and dipole-dipole sounding techniques agree well with laboratory measurements on water-saturated specimens from the same area. A small volume-compression coefficient at low pressures is indicated for the samples from one region even though the total porosity is quite large (8%). This small coefficient suggests that total porosity consists of a high ratio of circular pores to thin cracks. Furthermore, surface conduction along pore walls apparently outweighs conduction through the pore fluid itself for pore fluid resistivities of the order of 90 ohm m.