台灣位於環太平洋地震帶之西側，歷史上多起重大災難性地震海嘯發源於此處，因此台灣之海嘯研究為一重要之議題。為清楚了解台灣之海嘯潛在威脅，本研究研發地震-海嘯關係圖 (Seismic-Tsunami Relationship, STR)，分析可能之海嘯危害。STR以影響強度分析法 (Impact intensity Analysis, IIA) 為基礎，將研究區域以 Cornell Multi-grid Coupled Tsunami Model (COMCOT) 進行單元海嘯源之格林函數計算，計算結果以最大波高整理為IIA分布圖，並以地震尺度關係式 (Source-Scaling Relationship) 對照出等價之地震矩規模。透過STR，可快速評定各地點之海嘯威脅程度，除可排除無風險或低風險之區域外，更可精確掌握海嘯源之敏感區域。 1604年之泉州大地震與1771年之八重山大地震，此兩起事件於當地均有海嘯之記載，然而鄰近的台灣沒有相關之文獻紀錄。本研究將藉由STR法，搭配情境分析法還原該事件對台灣之影響，並進而分析台灣鄰近海域之海嘯高風險區域。由分析成果可知，台北以南及台南以北面臨來自台灣海峽之海嘯威脅；宜蘭地區對台灣東部海域之海嘯威脅極具敏感性；花蓮地區面臨來自琉球島弧之海嘯威脅；台東地區面臨著來自亞普海溝之海嘯威脅。 ;Taiwan is located on the west side of the Circum-Pacific Seismic Zone in which numerous of the catastrophic earthquake tsunamis were originated. As a result, the tsunami hazard evaluation is one of the important issues. In order to understand the tsunami threat to Taiwan in the surrounding waters, “Seismic-Tsunami Relationship” (STR) was developed to visualize any impact of possible tsunami hazards. “Cornell Multi-grid Coupled Tsunami Model” (COMCOT) was applied to calculate the Greens Function of each unit tsunami. The calculated results are arranged at the maximum wave height as IIA distribution. The corresponding magnitude MW of the result in the equivalent intensity was replaced with the “Source-Scale Relationship”. Through the STR, The tsunami threat can be quickly assessed in study areas. In addition to excluding risk-free or low-risk areas, an accurate distribution of the tsunami sensitive area can be obtained. The Quanzhou Earthquake in 1604 and the Yaeyama Earthquake in 1771 which both generated tsunamis and were recorded in their local area, while there is no relevant documentary record in Taiwan. Scenarios analysis and STR method were applied to understand the events in this study as well. According to the results, The western coast of Taiwan along Taipei to Tainan is facing the tsunami threat from the Taiwan Strait; the northeast Taiwan (Yilan region) is sensitive to the tsunami threat in the eastern waters of Taiwan. As for the eastern Taiwan, Hualien and Taitung are facing the tsunami threat from the Ryukyu Trench and Yap Trench, respectively.
