本研究係探討台灣沿海因地震所引起之海嘯危害，應用隨機滑移模型 來建立機率式海嘯危害度的分析模式。在危害度分析中引進時間維度量化 海嘯波高的發生率；使用隨機滑移模型來描述真實地震在其破裂面上之滑 移分布的不確定性，並由此了解複雜的破裂行為對海嘯所造成的影響。模 式應用上，以琉球海溝南段(臺灣花蓮外海)與其最大規模之地震事件為例， 探討分析海嘯危害與對臺灣的影響。在隨機滑移模型中，滑移分布隨著二 維隨機分布(X)上的重尾特徵改變，而此動作也影響了滑移分布在波數域頻 譜的冪律行為。在海嘯危害分析中，依k-square model 來產生多組的隨機滑 移分布，以此分布計算海床之形變與初始水位面後，進行模擬海嘯的傳遞 情形。由結果可清楚地觀察到不同的滑移分布造成波高時間序列與最大波 高的改變，表示即使在同一種地震條件下仍存在波高與傳遞時相位變化的 可能，並暗示著以往在評估海嘯危害時，忽略了海嘯波高的可能性，且有 機會低估海嘯的最大波高。本研究透過更為真實的模擬方式來評估海嘯的 危害度，得到比以往更多有關海嘯波高的信息，因而提供了更為完整的海 嘯危害度分析。;We conduct probabilistic tsunami hazard analysis (PTHA) of Taiwan region for earthquake sources (the maximum event) in the south part of the Ryukyu trench and present the annual rate of tsunami wave heights exceeding z. Stochastic model describes uncertain and heterogeneous slip distributions on the fault. The values of slip distribution are following the boundary of heavy tail for the 2D white noise (X) and that also makes the power law deviate to the k square model. In PTHA, we synthesize patterns of differently complex and heterogeneous slip distributions induced the vertical seafloor displacements by stochastic model. The results clearly show the tsunami prorogation is affected along with the slip distribution pattern changing. That means the behavior of real tsunami is not the same even under the same conditions and suggest we ignore the possibility of wave height as estimating the tsunami hazard before and have a chance to underestimate. This study supplies a more realistic method of the tsunami hazard analysis and obtains more information.
