Fem Analysis on the Slow Ground Motion

In control of a linear collider, the ground motion is one of the big problems. Various things can be considered as a factor of the ground motion, environmental vibration, atmospheric pressure variation, and the earth tides, etc. This time, we measured the slow ground motions using the tunnel of the underground hydroelectric power station "Shintoyone" located in the granite region. For the following reasons, we selected Shintoyone power station as a measurement field. a) The slow ground motion at the granite region can be measured in a tunnel. b) The slow ground motion by operation of generators can be measured in a tunnel. c) The slow ground motion can be measured moving a measurement position. (Because, the length of a tunnel is enough and has reached to the ground.) d) The slow ground motion by change of the water level of a dam can be measured. We report the measurement results of the slow ground motion, and the examination results in FEM analysis.