Comparison of earthquake motion between earth's surface and underground observed by strong-motion seismograph network (KiK-net) around ILC Kitakami candidate site

We have to show the world that there is no difficulty to construct and operate the ILC at Kitakami candidate site in spite of high earthquake activity in Japan. NIED established the nation-wide seismograph networks after the Great Hanshin-Awaji Earthquake Disaster. Many KiK-net stations are located near the ILC Kitakami candidate site. At each KiK-net station, a pair of strong motion seismographs is installed both on the ground surface and at about 100 meters below. In this paper we compared maximum acceleration observed at the ground surface and subsurface around the ILC Kitakami candidate site. We concluded that maximum acceleration at 100 meters below the ground surface is 1/5 times smaller than it on the surface. (author)