本團隊於近年研究「最強地震圓弧雙交叉」之地震分布結構，此種地震圓弧交叉結構在預測芮氏規模5.7以上之強震上有較好成效，本研究透過MATLAB 程式調整搜尋週期(dY)、徑向誤差參數(TOLRe)、度向誤差參數(TOLde)，進而改變地震圓弧之精度，分析1981年至2016年間臺灣地區在不同精度參數下搜尋到的最強地震圓弧雙交叉案例，本研究主要聚焦於搜尋週期(dY)不同對臺灣地區最強地震圓弧雙交叉之影響。本研究發現在最強地震圓弧雙凸交叉方面，當搜尋週期(dY)越大時找到之最強地震圓弧雙凸交叉數量越少；當設定搜尋週期(dY)=4時有最高之強震預測命中率；當設定搜尋週期(dY)=3.75、4、4.25、4.5時對70天內的強震預測而言為穩定高效率之搜尋週期(dY)。在最強地震圓弧圓形交叉方面，本研究發現最強地震圓弧圓形交叉對於極短天期之預測有一定效率，預測成功之最強地震圓弧圓形交叉皆在35天內預測到後續強震；最強地震圓弧圓形交叉好發於宜蘭縣蘭陽溪一帶、花蓮縣新城一帶及臺東縣知本一帶，分別對應琉球火山島弧及海岸山脈最北、最南端之板塊隱沒帶。本研究方法所得之強震預測命中率高於背景值，說明本研究方法具有一定意義，印證利用最強地震圓弧雙交叉進行強震預測之可行性。;The Strongest Double Intersection of Circular Arcs of Earthquakes (SDICAE) was studied by our team in recent years. It had been found that SDICAE is useful in predicting strong earthquakes with magnitudes over 5.7. We use MATLAB program to analyze the SDICAEs around Taiwan from 1981 to 2016 by assigning different values to the parameters dY, TOLRe and TOLde. We focus on the influence of different searching period(dY) of the SDICAE around Taiwan in this study. We have found that the amount of SDCICAE decreases while dY becomes bigger. The highest efficiency of the strong earthquake predictions is achieved when dY is equal to 4. The efficiency remains steadily high while dY is set to be 3.75,4,4.25, and 4.5. We have also found that SCICAE is efficient for the predictions of strong earthquakes within 35 days. SCICAEs usually appear in Yilan, Hualien and Taitung, which correspond to the Ryukyu Arc, and the subduction zones at the northern and the southern areas. The hit rate of the strong earthquake prediction obtained by this study is higher than the background value, which shows that this study has a certain significance and confirms the feasibility of the strong earthquake prediction by the SDICAE.
