Measurements have been made of the electrical resistivity, the acoustic wave speed, density, and water content of six groups of rock samples taken from Cenozoic volcanic units. It has been found from these measurements that the correlations between physical properties are significantly different in the case of volcanic rocks than in the case of sandstones and limestones. For a given porosity and water content, the resistivity of a volcanic rock is several fold greater than that of a sandstone or limestone. Also, there is a weaker correlation between acoustic wave speed and porosity in volcanic rocks than in sandstones and limestones. The effect of temperature on the properties of these rocks appears to be predictable from fundamental considerations to temperatures as high as 100/sup 0/C.