The South Kanto and the Tokai Districts were designated as an intensive observation area for earthquake prediction by the coordinating committee for earthquake prediction on February 1974. It was reported also, that the Tokai District has a great possibility to be hit by a big earthquake originated in the Bay of Suruga by the Seismological Society of Japan on October 1976.
Then the Geological Survey of Japan had constructed the automatic observation system of the ground water in the eastern part of the Tokai District, during a period from November 1976 to March 1979, as a part of the integrated observation system by the governmental organizations related.
This system are constituted:
1.12 observation wells for earthquake prediction which are installed with 6 water level,1 water quality and 8 radon concentration observation systems.
2. Data telemetering system to the Japan Meteorological Agency via the Geological Survey of Japan from these wells. The final goal of the project for Tokai big earthquake prediction is to catch the precauser of the earthquake, processing and analyzing the observation data derived from these system.

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A weighted residuals method based on Galerkin's finite element technique is applied to investigate the saltwater intrusion and dispersion in the coastal aquifer. The salt-water intrusion phenomenon was treated as the density-dependent flow of two immiscible and miscible fluids.
The mathematical formulation of miscible densitydependent flow consists of the coupled form of the flow equation and the convective diffusion equation.
The present analysis uses two dimensional quadrilateral, isoparametric elements with a linear basis function for piezometric head, salt concentration and velocity components.
From the comparison of the numerical results with the experimental results, this procedure can handle the saltwater intrusion in the coastal aquifer.

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[in Japanese]

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[in Japanese]

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