Modeling of Stress-Deformation Relationships in a Collision Belt: Taiwan

臺灣碰撞帶應力與變形作用的模擬

胡植慶(Jyr-Ching Hu) ； 安吉利爾(Jacques Angelier)

《Terrestrial, Atmospheric and Oceanic Sciences》 7卷4期 (1996/12) Pp. 447-465

並列摘要

Seismic refraction data from onshore and offshore experiments in theeastern-northeastern Taiwan region were used to study the velocity structureby the two-dimensional ray-tracing method.In the velocity model,astructural fault boundary located beneath the Longitudinal Valley was usedto separate the northern Coastal Range(CR)on the eastern side from theeastern flank of the Central Range(EFCR)on the western side.The P-wave velocities from the surface to the depth of 12-15 km varied from 3.9 to5.8 km/s beneath the CR and from 4.8 to 6.1 km/s beneath the EFCR.Comparingthe velocity structures along various latitudes,it was found that theCR extends northward to 24.2°N.The velocity structures of the CR,theHsinchen Ridge(HR)and the Yaeyama Ridge(YR)indicate that the HRand the YR both belong to the same type of tectonic unit as the CR.To thenorth of 24.2°N,the velocity structure of the Ilan Ridge(IR),located betweenthe EFCR and the southwestern end of the Ryukyu arc,is similar tothat of the EFCR;hence,probably indicating it is the northeastern extensionof the EFCR.This suggests that the EFCR bends eastward and belongsto the same tectonic unit as the southwestern Ryukyu arc.From acomparison of the velocity structures of the CR,EFCR and of other typicalcontinental arcs,orogens and oceanic arcs in the literature,it can be concludedthat the northern CR belongs to an oceanic arc and that the EFCRis a continental arc.Further more,from the analysis of the velocity structuresbeneath the CR and EFCR,it is believed that the upper crust of theCR is weaker in strength than the EFCR,which means that the arc-continentcollision is not an appropriate model for the formation of Taiwan island.

並列關鍵字

Numerical Simulations ； Mechanical Decoupling ； Geological Discontinuities ； Stress and Velocity Fields