To simply and accurately detect the behavior of underground water in an arbitrary stratum by making a structure simple.
In a detector, an integral-type core material 11 is constituted by coupling a plurality of unit cylinders 1a and 1b to each other by means of cylindrical joints 1a and 1b, and a plurality of electric cables 12 and 12' for an electrode and a common electrode, which are constituted by covering a surface of a conductor with an insulator, are each arranged on the outer peripheral surface of the core material along an axial direction. In the detector, a conductive part is formed for the electric cable for the electrode by removing the insulator in one predetermined place in each axially different position; the common electrode is formed for the electric cable for the common electrode by removing the insulator in a place corresponding to the axial length of each unit cylinder, so that an electrode type water-level sensor can be constituted; and a water pressure sensor 13 is provided in each of the joints in such a manner that a pressure acceptance part faces an opening provided in the peripheral surface of the joint.
KITAMURA HIDENORI
Satoshi Kono
Makoto Nakamura
Kurata Masatoshi
Sadao Muramatsu
Ryo Hashimoto