Аннотация:Mechanism of sediment movement and long-term deformation of sand and gravel beaches in the Hyuganada Sediment Cell, Miyazaki Prefecture, were investigated on the basis of comparisons of shoreline position in old maps and aerial photographs for the period of 200 years. Significant coastal erosion in the northern region and slight shoreline advance in the southern region were identified. Huge amount of sediment retention in reservoirs with a rate of 1.9 million cubic meters per year was considered to decrease the sediment supply to the sea through four major rivers. Physical properties of sand particles, such as particle size and thermo-luminescence intensity, indicated the direction of alongshore sand transport to be southward, which was consistent with macroscopic analyses.
