Abstract
The typhoon No. 18 in 1999 caused serious damage in the coastal facilities in Suo-Nada sea of Yamaguchi prefecture. The storm surges and wave heights became lager than the present defensive standard level in some areas. The typhoon route, atomosheric pressure depth and storm surge anomaly in the standard level were revised on the basis of probabilistic estimation. The new standard employed the typhoon No. 18 as the representative model typhoon in Suo-Nada sea. The newly proposed sea wall level became much higher than the present height in almost areas in Yamaguchi coast.
