2008 年 24 巻 p. 273-278
A field investigation has been carried out to investigate the damage of coastal, port and harbour facilities caused by the Niigataken Chuetsu-oki Earthquake in 2007. The instrumental JMA seismic intensity of a strong 6 was registered in Kariwa village, Kashiwazaki and Nagaoka cities, in Niigata, Japan. The damages to coastal, port and harbour facilities were investigated. The old seawalls at Osaki coast in Kashiwazaki were broken due to strong seismic motions. Several coastal facilities ware partly broken due to liquefaction occurred by the severe ground shaking. The corners of concrete caissons used for a breakwater were broken off due to strong collisions. There are many old woods appeared on a sea bottom surface after the earthquake in the region offshore from Izumozaki town to Kashiwazaki city. The woods might appear to floating up to the sea bottom surface due to the liquefaction of sea bottom sediments.