Investigation and Restoration Countermeasure Work for the Slope Disaster Induced by the 2005 West off Fukuoka Earthquake

The slope disaster and damage in Genkaijima, induced by the 2005 West Off Fukuoka Earthquake, have been investigated and studied by the investigating commission organized by the Japanese Geotechnical Society. The slope disasters in this island are classified into three areas: (1) damages of the housing site foundations and the retaining walls of steep slopes in the resident area, (2) landslides over the circumference road of the island, (3) small-scale collapses and cracks on the eastern slope from the Genkai elementary school to the Genkai junior high school. For each area, the results from on-site inspections, filed tests, indoor tests, measurements and analysis are reported together with the suggestion on restoration countermeasure work in this paper.