Abstract
Due to Fukuoka Seiho-oki Earthquake “M7”, the slope failure occurred among the islands facing Hakata Bay and in the slope region of the peninsula. This report was based on the joint research conducted between Survey group of JSCE and Survey group of JGS and wrapped up about the actual situation and the failure form seen in Genkai island, Shikanosima island and Itoshima Peninsula, where are very close to the hypoenter. In Genkai island, the settlements of decomposed granite soil of granodiorite and a failure phenomenon with opening crack were mainly observed. In Shikanoshima island, the surface failure were recognized in the slope areas of the western part of island where the circuit road runs and a large scale of rock failure were seen in the slope of the eastern part. In Itoshima Peninsula, a small scale of surface failure of decomposed granite soil, sliding on the embankment in the forestry roads and a small scale of rock fall from the rock exposure were observed. Each case has a failure form different from it in a heavy rain.
