Introduction: A New Geophysical Exploration Tool-Array CSMT/MT Method

Abstract

Japan is well known as one of the most active volcanic countries in the world, arid it is well endowed with geothermal energy like as the Philippines.

As of November 1996 there are 15 geothermal power plants in operation with (I total generating capacity of 530 MW. According to the electricity supply target announced by the Government, geothermal generation at the end of the par 2000 should be 600 MW (0.2% of total generation).

In order to approach this target and to investigate deep seated geothermal reservoirs, it is required to investigate and to identify fractures related to geothermal resources at depth.

The New Energy and Industrial Technology Development Organization (NEDO) have been promoting "Analysis and Evaluation on Exploration Methods for Fractured Type Geothermal Reservoirs". In addition a new Electro magnetic Exploration: Method, Array SSMT and its development has been studied since 1990 as one of the new geophysical exploration technologies.

In September 1994, on the completion of this technology, the New Energy Foundation (NEF) introducd arid adopted this method for a geothermal promotion survey in Shibetsu-dake, Hokkaido, and also in ashiro area. Iwate Pref. in 1995.

Despite the steep topography, the results of 2-D analysis in these survey areas, revealed clearly the hidden faults arid alteration at depth, and the exploration drillings based on the results of this survey successfully hit the high temperature reservoir at the depth.