Source location studies of AE events in rock samples are interesting and important aspects of rock physics. The first study was carried out by Scholz (1968) on cylindrical specimens of Westerly granite under uniaxial compressive stress conditions. Then, Mogi (1968) carried out source location measurements on beam-shaped specimens of various rocks under bending load conditions. While reviewing these early studies Hardy (1972) stated the following:

“Although Scholz’s studies represent a pioneering effort in laboratory scale acoustic emission source location in geologic materials, with the limited studies carried out, and the questionable location accuracy (χi ≈ 0.1 in.), the results should be considered with caution. Recent comments by Harding (1970) and Mogi (1968) further reinforce this opinion. Probably the most outstanding laboratory source location study carried out to date with respect to geologic materials is that by Mogi (1968). In order to provide a simple geometry, Mogi utilized beam shaped specimens deformed under four-point loading. During these studies Mogi investigated specimens of three marbles, three granites, a trachyte and an andesite.”