Abstract
Erosion of sand dune was investigated on Miyazaki Coast located east side of the Kyushu Island facing the Pacific Ocean. The erosion has been significant since early 1980's and accelerated since 1994. The average speed of the dune retreat was estimated at 2m/year recently accompanied with the gradual decrease of the dune height. The dune erosion in 2011 was found to be due to successive attack of three typhoons. The erosion was observed to be most significant by Typhoon No. 12 attacked in August. Combined effects of successive high waves to nearshore topography as well as long duration of high waves appeared to be influential to the erosion.
