Physical Modeling on the Plate Subduction at Manila Subduction Zone

• Main Authors: Hsieh, Chien-Yi, 謝見義
• Other Authors: Yang Rong Kuan
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/20734032068337870925

碩士 === 國立中央大學 === 地球物理學系 === 85 === Physical modeling test is an approach to the study of tectonic development. Properly scaled physical modeling tests have been performed to testify the development of the plate subduction along Manila subduction zone(MS), and the evolutionary development of the recently-initiated west-dipping subduction( Sw) along Luzon arc. The lithospheric model consists of the continental (the Asian Plate; AP) part and the oceanic (the Philippine Sea Plate; PSP) part as separated by a wedge-shaped opening. A low-viscosity asthenosphere underlies the lithosphere. Plate collision /closure is driven by a strip piston. The southward closure of MS results in stress concentration at the western side of the arc, and when the yield limit of the arc in PSP has been overcome an east-dipping fault develops. With the increasing accumulated stress due to plate collision, the fault transforms into a subduction zone(SE) and begins to extend southwardly. The already closed northern part of MS may correspond to the boundary between Hsuehshan Range belt and Backbone Range belt in central Taiwan, while SE corresponds to the Longitudinal Valley Fault. The 1-km thick accretionary sediment in the Luzon trough about 130 km to the south of Taiwan comes mainly from continental margin. Since SE is shifting westward, MS will be hidden under SE in future 0.5 my. When the west dipping subduction zone(SW) is initiated by an inclined cut made at the west side of the northern part of the arc within PSP, an east-dipping subduction zone will form at the east side of the arc some 160 km away to the south of SW after 1.1 my. Both the tips of SW and the new east-dipping subduction zone will extend southwards and northwards respectively, this extension will continue to happen until an east-west oriented uplifted zone forms in between both tips.