台灣西南海域山崩海嘯之數值模擬

Abstract

海底山崩海嘯指的是一種因為海底山崩所造成的海嘯，自從1998年巴布亞紐幾內亞(PNG)海嘯事件後，海底山崩海嘯逐漸受到學者們的重視，但海底山崩海嘯相較於一般常見的地震型海嘯不確定很高，且在參數的取得上並不容易，需要詳細的地質調查才可以取得相關的參數，因此海底山崩海嘯研究在所有型態的海嘯中可以說是最艱難的一個。 本研究利用山崩海嘯半解析解加上FUNWAVE-TVD來進行有關台灣西南沿海山崩海嘯的模擬，首先透過1998年PNG山崩海嘯來驗證模型的可行性，然後利用台灣西南海域的相關海底山崩數據來進行山崩型海嘯的情境模擬，並利用最大波高圖及測站時序圖來解釋模擬的結果。 在台灣西南海域山崩海嘯模擬結果中，我們發現了台灣西南海域的海底地形會導致邊緣波產生，且邊緣波會持續影響約一個小時的時間，會讓台灣西南沿海受到海嘯影響的時間拉長。最後，本研究亦提供了一個假設海底山崩參數的方法，希望這個方法可以提供往後研究山崩型海嘯的相關人員一個選擇。

Landslide tsunami is the tsunami that generating by landslide. After PNG (Papua New Guinea) tsunami event on 1998, academic has focused on landslide tsunami. But landslide tsunami is more uncertain than seismic tsunami, and it is very difficult to get the parameters of landslide. If we want to get accurate parameters, we should conduct very detailed research on geological oceanography. In summary, Landslide tsunami is the most difficult research of all kind tsunami. In this study, we use semi-analytical landslide tsunami generation model and FUNWAVE-TVD to simulate landside tsunami in southwestern coast of Taiwan. First, we validated feasibility of model by the scenarios for PNG tsunami event on 1998, and used submarine landslide data of southwestern coast of Taiwan to simulate propagation of landslide tsunami, then used maximum wave heights map and gauge record to analyze result of simulation. The results of landslide tsunami in southwestern coast of Taiwan find submarine topography can generate edge wave, and edge wave would affect southwest coast of Taiwan for one hour. And edge wave will extend time of tsunami impact in southwest coast of Taiwan. Finally, we provided a method to assume submarine landslide parameters in this study, and we hope this method can give person a choose for researching on landslide tsunami.