Forecasting of damage level of damaged maritime structures and estimation of degree of risk on coasts due to storm surge and wind waves caused by typhoons

经过九州岛的台风有许多路线。台风每年袭击九州岛几次。在西部的熊本县和长崎县，风暴潮和风浪对海上建筑物的破坏频繁发生。这些县的海岸线很复杂。它面对着开阔和封闭的海域。面对这些地区的海岸线具有不同的地形特征，针对台风的每条路径，作者提出了四种预报海岸线沿线海工建筑物破坏程度的方法。第一种是最大风速(MWS)方法。MWS方法以北纬30°N台风中心附近的最大风速为基础，其次是量级方法。根据最大风速和台风大小定义了震级方法。第三种是等效波能(EWE)法。基于最大风速和吹风持续时间…定义了EWE方法更多的是台风。第四种是中心压力法。以北纬30°N台风中心气压为基础，定义了台风易损性指数CP方法，并利用该方法估算了同等级台风在北纬30°N各岸的易损性指数。利用该易损性指数，可以估算出台风经过北纬30°时，台风来袭对各海岸海洋结构物造成的破坏程度。由于风暴潮和风浪的影响，台风对海上建筑物造成了巨大的破坏。将作者提出的四种预报方法应用于9918号台风对沿海海洋结构物损伤程度的评估。结果表明，该预报方法可用于预测台风来袭前沿海海上建筑物的破坏程度，为估计台风对沿海地区的风险程度和影响程度提供了可能。该预报方法将用于防灾工作中的海岸带管理。此外，它还可以为沿海居民提供风暴警报和疏散信息。较少

Typhoons which pass through the Kyushu Island have many courses. Typhoons strike the Kyushu Island a few times a year. Damage of the maritime structures by storm surge and wind waves frequently occurs in the western two prefectures, Kumamoto and Nagasaki Prefectures. The coastline in these prefectures is complex. It faces open and closed seas. The coastline facing these areas has different topographical characteristics.The author proposes four kinds of method for forecasting the damage level of maritime structures along the coastline at each coast for each path of typhoon. The first one is the MWS (maximum wind speed) Method. The MWS Method is based on the maximum wind speed near typhoon center at latitude of 30°N. The second one is the Magnitude Method. The Magnitude Method is defined based on the maximum wind speed and the typhoon size. The third one is the EWE (equivalent wave energy) Method. The EWE Method is defined based on the maximum wind speed and the duration of wind blowing … More of typhoon. The fourth one is the CP (central pressure) Method. The CP Method is defined based on the central pressure of the typhoon at latitude of 30°N.The index of vulnerability of each coast for the typhoons of same rank at latitude of 30°N is estimated by the method mentioned above. By using this vulnerability index, the damage level of maritime structures by a coming typhoon at each coast can be estimated when the typhoon passes through at latitude of 30°N.In 1999, Typhoon 9918 struck Kyushu Island. Due to the storm surge and wind waves, the typhoon caused enormous damage to maritime structures. The four kinds of forecasting method, which is proposed by author, is examined to estimate the damage level of damaged maritime structures along the coast caused by Typhoon 9918. The result shows that the forecasting method can be used to estimate the damage level of maritime structures that will occur along the coast before a typhoon strikes.The method, which developed in this time, shows possibility of the estimation of degree of the risk and influence of typhoon on the coasts. The forecasting method will be used for the purpose of coastal zone management in disasters prevention works. Further, it is useful for information of storm warning and evacuation for residents along the coastlines. Less