The Study for the Offshore Earthquake Swarms in Southern Taiwan and Manila Subduction

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基本資料

Project title

Code/計畫編號

NSC101-2116-M019-004

Translated Name/計畫中文名

台灣南部外海地震群與馬尼拉隱沒構造研究

Project Coordinator/計畫主持人

Yi-Ling Huang

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Institute of Earth Sciences

Website

https://www.grb.gov.tw/search/planDetail?id=2632082

Year

2012

Start date/計畫起

01-08-2012

Expected Completion/計畫迄

01-07-2013

Bugetid/研究經費

538千元

ResearchField/研究領域

地球科學
防災工程
海洋科學

"馬尼拉隱沒構造牽涉到台灣島的形成，構造十分複雜，大致呈南北向，由北緯13 度沿著呂宋島的西側向北伸展至北緯23 度左右，綿延約1500 公里，聚合速率可高達每年8 至9 公分。以北緯20 度為界，以南之馬尼拉隱沒系統仍為較單純的板塊隱沒環境，以北的區域已逐漸轉變為隱沒跟聚合碰撞同時出現的環境，約於北緯21 度後，其形貌完全失去海溝所具有的特徵，因此有研究主張馬尼拉海溝並未向北延伸進入臺灣南部及西南海域。受限於此區域為海域、野外資料的收集不若陸上工作容易，過去在此區域的研究仍屬較少，且外海地震受限於是網外地震，在定位的準確度上有所不足，無法對此區域深部地殼構造及孕震機制解釋提供相關幫助。本計畫擬使用中研院地球所於TAIGER（TAiwan Integrated GEodynamics Research）計畫執行期間佈設於台灣陸上之線性陣列所收集到之三群位於墾丁外海的地震群資料、加上IRIS（Incorporated Research Institutions for Seismology）及NEIC（National Earthquake Information Center, USGS）等單位之全球網資料，並結合TAIGER 計畫執行期間於台灣南部海域進行多次震測所求得的地下速度構造剖面，對這三群發生於馬尼拉隱沒系統北段的地震群重新定位，並挑選規模較大的地震事件嘗試求取震源機制解，探討其震源、發震機制、與馬尼拉隱沒系統間的關係，藉以釐清此區域地體構造與台灣島形成之關聯。" "Manila subduction system is complicated and involved into the formation of Taiwan orogeny. It is toward from south (13°N) to north (23°N) and total length is about 1500 km. The velocity of convergence in this region can be 8 to 9 cm/yr. In the part which is to the south of 20°N, the system shows a pure subduction environment. It shows a subduction and convergence mixing environment in the part which is to the north of 20°N, especially the part to the north of 21°N, the system represents a pure convergence- collision feature. Thus, some researchers suppose that the Manila trench does not extend into southern Taiwan area. Due to the limitation of doing the field work in offshore area and the data collection is not easy as onshore, researches about Manila subduction are fewer. In addition, offshore events usually occur outside of observational network, it causes uncertainty of doing location calculation and difficult to provide useful information for discussing the seismogenic mechanism in this area. The aim of this study is to combine the records of a linear array which were set during TAIGER（TAiwan Integrated GEodynamics Research） project, the data comes from IRIS (Incorporated Research Institutions for Seismology), and the data comes from NEIC (National Earthquake Information Center, USGS) to relocate the events of three offshore earthquake swarms which occurred in southern Taiwan area. Furthermore, some data of larger event will be selected for fault plane solution calculation. The results of relocation and fault plane solution will provide some evidences for discussing the relationship between source mechanism, plate tectonics, Manila subduction system and Taiwan orogeny."

Keyword(s)

馬尼拉隱沒系統
地震群
重定位
Manila subduction zone
earthquake swarms
relocation

DSpace CRIS

The Study for the Offshore Earthquake Swarms in Southern Taiwan and Manila Subduction

基本資料

Description