台灣地區最大地動加速度研究

Abstract

台灣位於環太平洋地震帶上，受到歐亞大陸與菲律賓海板塊互相碰撞的影響，1991年至2004年間的每年平均無感地震為8271次，有感地震為489次。預防地震所造成之破壞、減低震災的損失，就一直是政府的施政重點。也因此，了解何處容易釋放較大能量及何處容易發生地震是相當重要的研究方向。 本研究利用1994至2005年間臺灣地區之強地動觀測計畫（Taiwan Strong Motion Instrumentation Program, TSMIP）完整記錄台灣區的強地動資料，找出各地震測站在這十二年間所遭受的最大地動值及各級地震的地動次數，以估計各地區的震災潛勢。 研究結果發現，1994至2005年間全台地震最頻繁的是宜蘭南澳一帶，最大地動加速度（Peak Ground Acceleration, PGA）最大的地區是在台東成功一帶。其他受地震侵襲較多且較大地區包括嘉南地區，花蓮縣新城、秀林地區附近及台東縣長濱、東河一帶，政府及民眾應加強防災措施及嚴格落實防震法規。Taiwan, on the earthquake belt of Pacific Ocean, has been affected by collision happening between Eurasia continent plate and Philippine Sea plate. From 1991 to 2004, there were 8,271 non-sensible quakes and 489 sensible ones averaged every year. It’s always the main course to prevent and reduce the damage caused by the earthquakes for the government of Taiwan. By the same token, finding out the areas containing huge energy to release and the ones liable to have quakes is also the important issue for the seismologists. The purpose of this study is trying to estimate the potential of seismic activities in each region. Taiwan Strong Motion Instrumentation Program (TSMIP), executed from 1994 to 2005, is employed to record the data of strong motion in Taiwan. It’s to know the most PGA as well as the motion times of the quakes in each range filed in the observation posts during the past twelve years. According to the results of this study, among all the regions in Taiwan, the most frequent earthquakes happened in the neighborhood of Nanao, Ilan and the most PGA（Peak Ground Acceleration）is in Chengkung, Taitung from 1994 to 2005. The areas struck frequently by the earthquakes which were scaled high include Chiayi, Tainan, Sincheng and Siouling in Hualien, and Changbin and Donghe in Taitung. Therefore, it’s necessary to enhance the methods to prevent the damage caused by the quakes for the government and the common people. And they also need to implement the regulations of earthquake prevention exactly.