Hot Springs, Geothermal Fields and Plate Tectonics in Japan

Abstract

Hot springs are, in general, situated in the volcanic belt of a convergent zone and are utilized as indicators of geothermal potential in an area. The locations of hot springs (with temperatures;>900 C) in Japan, have been examined to determine the influence, plate underthrusting exerts, in determining the locations of these hot springs. Thi. examination shows that hot springs and geothermal fields in Japan are situated i~ the volcanic areas along the extension of zones which mark discontinuities in plate underthrusting. Measured heat flow in many of these zones is higher than average for volcanic areas. Such zoneS with higher than average crusta1 temperatures should be prime targets for comprehensive geothermal exploration programms.