馬尼拉隱沒帶為南中國海地區最有可能發生引發大規模海嘯的地震帶，本研究計畫利用表面波的觀測，研究此地區的速度模型。台灣-菲律賓隱沒系統應作一整體性的研究，但長久以來，因地震臺站的分布不均，使得台灣附近的速度構造有詳細的研究，但菲律賓附近的速度構造卻僅有粗略的瞭解。我們計畫一方面進行至菲律賓設站前置作業，二方面利用現有資料進行分析。設站方面，將使用我們現有的短週期地震儀，至馬尼拉西南方的島嶼，監測隱沒帶地震的活動，但此計畫得仰賴菲方人員的協助，不確定性較高。資料分析方面，我們將利用在菲律賓端發生的淺層地震，由台灣端的測站所接收的表面波資料，分析此一路徑之平均表面波波速頻散曲線，並進行反演求得速度構造。全球地震網在菲律賓亦有一臺站，我們也將利用台灣端地震的表面波資料，進行反向路徑的分析，以期對台灣-菲律賓隱沒帶的構造，有更進一步的瞭解。 ; The Manila trench is deemed as the most potential zone of significant tsunamigenic earthquake in the South China Sea area. While the velocity structures near Taiwan are well studied, those near the Philippines are relative unknown as a result of uneven distributions of seismic stations. The first part of the proposal is to deploy a linear short period array on the Lubang island to better locating in situ earthquakes, both shallow and intermediate depth, which will be used to delineate the subducting plate. While schedule of deployment remains uncertain pending on the help provided by the PHIVOLCS, second part of the proposal is to use surface waves of the Philippine earthquake, as recorded by BATS stations, to study the shear wave velocity structure along the Manila trench. The group velocities of fundamental mode Rayleigh wave will be determined by multiple filter analysis. From the derived velocities, we will deduce the surface wave dispersion curve indicative of the average velocities over the ray path. Finally, velocity models as a function of depths will be inverted from the dispersion curve for representative ray path. We will look into the trench normal variations of the velocity structures. The Computer Programs in Seismology package will be employed to conducted the analyses. ; 研究期間 9808 ~ 9907
