著者

西田 泰典

出版者

北海道大学大学院理学研究院

雑誌

北海道大学地球物理学研究報告 (ISSN:04393503)

巻号頁・発行日

vol.76, pp.15-86, 2013-03-19

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The self-potential (SP) method is based on measuring the natural electric potential differences, which generally exist between any two points on the ground. The SP fields have their origins in different mechanisms which can be used to identify ore deposits, geological features, ground water flow, and hydrothermal systems. The amplitude has a very wide spectrum, from a few mV/km to a few V/km, and their spatial distribution is correlated with the size of sources that lie at a depth within several hundred meters depth. Despite the fact that SP studies have been carried out by many researchers in the past, especially in field of mine prospecting, the use of the method had been restricted because the sources of SP anomalies were not fully identified and the development of other geophysical methods, such as seismic, electromagnetic and gravimetric methods, was very fast. However, since 1970, the SP method has again risen as a modern prospecting method for delineating the thermal state of geothermal fields. These studies have encouraged the application of the SP method to volcanological, geothermal, hydrological, seismological studies and so on. Spatial and temporal measurements of the SP field may prove to have the advantage of sensing dynamic aspects of the tectonic activities. This article will focus on fundamentals of theoretical and experimental SP studies and will show many field examples to guid for beginners.