Volcanic mountain area disaster in the Iwate-Miyagi Nairiku earthquake

摘要

We conducted a geotechnical damage investigation for the disaster during the earthquake onrnJune 14, 2008. An earthquake of magnitude 7.2 hit a volcanic mountain area of northern inland Japan. As arnresult of the earthquake, a landslide of 1.5 million m~3 generated near the top of the mountain became a mudrnflow and descended 10km. The geomorphic characteristics of the mud flow are reported. Another hugernlandslide was generated upstream near the Aratosawa dam. It was about 1.3 km in total length, about 900 m inrnmaximum width, and a sliding mass of about 67 million m~3 slipped about 320 m. The geological features, therntime series of the slide and the cause of the slide are also discussed. In this paper the geotechnical propertiesrnof the damage are introduced.