Mr Ikeda, a post-graduate student at the University of Kyushu and the man in charge of the university's MT project, checks out data on a notebook with Phoenix's field manager, George Elliott Suffering through more earthquakes than any other country in the world, Japan is certainly considered "seismically active"
To understand just how and why earthquake occur (and someday to predict when) it is necessary to make detailed studies of Earth's deep structure. Magnetotelluric (MT) is one of the few techniques capable ot investigating the Earth's crust deeply enough to be useful.
The Geological Survey of Japan has user two Phoenix V5-MT systems since 1988 to study the transecting structure of japanese islands. In 1994, four more V5-MT systems were delivered to earthquake and volcanology research institute of Kyoto University and Tokyo University. All the systems are beeing used by their owners as well as other universities and institutes throughout Japan. A feature of this research unique to Japan is the comprehensive "multi-institute, multi-annual" field survey using shared geophysical equipment. Phoenix vice-president Mitsuru Yamashita has translated a portion of the report, Collected Papers of 1995 Conductivity Anomaly Research Meeting available to interested readers on request.
Beside studying the Earth's structure, scientists from many countries (China and Greece are two) have reported deep-seated resistivity changes when earthquakes occur. (The atest development in this field were summarized in the book Electromagnetic Phenomena Related to Earthquake Prediction, editors M. Hayakawa and Y Fujinawa, Terra Scientific Publishing Co., Tokyo, 1994, 677 pages).
Stationary networks of monitoring equipment are needed how to further our knowledge of deep resistivity changes wich may be related to earthquake prediction. Early in 1996, two stationnary V5-MT systems will be installed in Mizusawa and Esashi, Geodetic Observatories of Japan's Geographical Survey Institute. The permanent installation facilities are now under construction. The systems are networked by telephone lines between Mizusawa, Esashi and Tsukuba Science City in order to carefully monitor deep-seated resistivity changes continuously in real time.
Phoenix has adapted and enhanced its V5-MT system for this new and exciting application. Changes include the use of GPS-synchronized clocks, enhanced telecommunication capabilities and simultaneous multi-band data acquisition.
Mitsuru Yamashita |
