2018年底，印尼連續發生兩次海嘯事件。第一次為9月28日之2018 Sulawesi earthquake and tsunami (SET)。另一次為12月22日2018 Sunda Strait tsunami (SST)。這兩次海嘯有一共同之特色：皆不是傳統的地震型海嘯。SET 的特點在於該事件中有規模7.5之走向滑移的地震發生，然而僅由如此規模之地震，並無法引起該事件中7公尺或更高之海嘯。SST則是完全沒有地震的警訊，海嘯突然在當地晚間約9:27抵達。這兩次的海嘯事件真的發生的原因，目前尚未得知，可能是海底山崩，也可能是額外的海床變動。要深入了解這類型的海嘯，找出海嘯源所在位置為第一步。本年度之研究將接續去年之成果，將發展完成之海嘯影響強度分析法（IIA）與海嘯到時分析法（TATA），應用於分析SET之海嘯源。IIA法可快速濾除海嘯源低度影響之區域，有效減少海嘯情境個數。然而對於方向性較強之海嘯，則較不容易掌握。而新開發之海嘯到時分析法（TATA）則可以克服此一弱點。非地震型之海嘯主要成因為海底斜坡山崩及海底火山山崩。台灣歷史上之1867基隆海嘯與1781高屏海嘯皆有學者指出可能為非地震型海嘯。本計畫除分析SET外，亦將進行上述台灣歷史海嘯事件之分析，並以非連續雙黏性流模式，完整模擬山崩引發海嘯之過程。希望透過對於海嘯源深入之了解，以掌握潛在之非地震型海嘯之災害。 ;At the end of 2018, two consecutive tsunami events occurred in Indonesia. The first one was the 2018 Sulawesi earthquake and tsunami (SET) on September 28. The other was the 2018 Sunda Strait tsunami (SST) on December 22. These two tsunamis have one thing in common: they are not traditional earthquake tsunamis. The SET occurred with an earthquake of magnitude 7.5. However, only by an earthquake of this magnitude could not trigger a tsunami of 7 meters high or higher in this event. The SST was not event triggered by an earthquake. The tsunami suddenly arrived at about 9:27 PM in the local time. The causes of these two tsunami events still remain unknown. A submarine landslide or an additional seabed vertical displacement may play a role. To gain a deeper understanding of these tsunami events, finding the location of the tsunami source is especially important. The new research this year will follow the results from last year and apply the developed methods of impact intensity analysis method (IIA) and tsunami arrival time analysis (TATA) to analyzing the tsunami source in the SET event. The IIA method can quickly filter out the areas with low impacts of the tsunami sources and effectively reduce the number of tsunami scenarios. However, for a tsunami with a strong direction, it is less easy to grasp. The newly developed Tsunami Time Analysis Method (TATA) can overcome this weakness. The non-seismic tsunami is mainly caused by landslides on the seabed or submarine volcanic landslides. In the history of Taiwan, the 1867 Keelung tsunami and the 1781 Kaohsiung-Pingtung tsunami were possibly non-seismic tsunami events. In addition to analyzing the SET, this project will also conduct an analysis of the above-mentioned historical tsunami events in Taiwan. The discontinuous bi-viscous model (DBM) will be used to perform the complete process of landslide-generated tsunamis. It is hoped that through the profound understanding of the tsunami sources, we will be able to tackle the potential non-seismic tsunami disaster in Taiwan.
