抄録
Multi-fan beam data shows detailed bathymetric features off the Miho Peninsula, shizuoka Japan. Comparisons between recently acquired bathymetric data sets and past date collections show systematic differences in sedimentary regime of this area. Northern part of the area is characterized by the deposition on the sea floor and progradation and the southern part by the retrogradation and erosion. Several gravitational sediment flows composed of the deposition swell and down slope sand ridges are clearly delineated by the 3D image from multi-fan beam data along the southern coast where intensive coastal erosion has been taking place since 1983. Benthos fauna is examined on the basis of dredge samples from this area. This study indicates that benthos fauna appears to be related with the sedimentary regime. Drastic decrease in biomass of Macrobenthos from 360.5g in 1971 to 168.0g in 2004 is observed and suggests erosional effect on benthic biological community last 33 years.
