菲律賓明多洛島(Mindoro)地處台灣─馬尼拉海溝系統的最南端，與最北端的台灣相較之下，有許多相似的地質特徵，例如海溝與由地震分布表現的隱沒帶(Wadati-Benioff zone)在進入本島內部時，都失去蹤跡、在台灣和明多洛本島內部都有因碰撞形成的崇高山脈。因此，在台灣的地質研究課題，可以應用到明多洛，包括：(1) 從隱沒到碰撞是如何轉移的，轉移的位置何在？(2) 在碰撞之前的隱沒板塊，呈現何種應力狀態？(3) 在本島內部消失的隱沒地震帶(Wadati-Benioff zone)，是因隱沒板塊的消失？還是存在著無地震的古隱沒板塊？這些課題的研究成果，除了可以瞭解明多洛的形成演化外，也可以經由對比，更加瞭解台灣的形成演化，進而對整個台灣─馬尼拉隱沒系統，有更深一層的認識。為從事以上的研究課題，我們在上一個計畫提出設置一個包含九個(五個將設置在明多洛西北部、四個在呂宋島南部)短週期地震儀的地震陣列，用來更佳描繪台灣─馬尼拉隱沒系統最南端的隱沒板塊形貌。經由菲律賓火山地震觀測所(PHIVOLCS)的協助，我們已成功的在明多洛西北部及呂宋島南部設置十個短週期地震儀，初步的資料回收也顯示該地區的高地震活動度，驗證此計畫的科學價值。這次提的是上一個計劃的延續性計劃，主要工作包括後續的儀器維護、資料回收及資料處理工作。我們預計每隔四或五個月進行資料回收工作，若回收時遇有儀器故障，則進行故障排除動作。我們預計在下半年度開始資料處理工作，包括地震活動度分析、地震定位及速度構造逆推。期間，我們會備妥並熟稔資料處理所需之軟體。以上工作將與菲律賓火山地震觀測所(PHIVOLCS)密切合作，經由此計畫的合作經驗，將有利於未來其他合作計畫的推廣。 The island of Mindoro locates on the southernmost tip of the Taiwan-Manila trench system. Some geological features here resemble those of the northernmost tip in Taiwan, e.g., the termination of trench and Wadati-Benioff zone as we traced into the interior of the island, and the high mountain range in the central part of the island. It is interesting to raise the following similar questions in Mindoro. (1) How and where the transition from subduction to collision occurs? (2) What are the slab stress patterns? (3) The lacking of the Wadati-Benioff zone beneath central Mindoro is due to the absence of slab or the presence of an aseismic slab? To tackle the aforementioned questions, in previous project, we proposed to deploy a seismic network of nine short-period stations (five in northwest Mindoro and four in south Luzon) to better delineate the Wadati-Benioff zone at the southernmost tip of the Taiwan-Manila subduction system. Through the help and cooperation of PHIVOLCS, we have successfully deployed ten short period instruments throughout the northwest Mindoro and south Luzon. The preliminary data retrieved indicated high seismic activities in the region, further attest the scientific significance of the project. The project we proposed this year is basically an extension one continued from previous project. The main tasks include instruments maintenance, data retrieval, and data processes. We plan to retrieve data every four or five months. If instrument malfunctions are found when retrieve data, necessary steps will be conducted to keep stations in functional conditions. We plan to start processing and analyzing data in the second-half period of the project. We aim at deriving results such as assessments of seismic activities, earthquake relocations, and tomographic images. Between now and then, we will get acquainted with the software and schemes necessary for data processing and analyzing. All the above work will be conducted in a manner closely cooperated with PHIVOLCS. The cooperation experience with seismological group in PHIVOLCS would significantly help future related projects to be conducted in the Philippines. 研究期間：10008 ~ 10107
