胡植慶2006-07-252018-06-282006-07-252018-06-282004http://ntur.lib.ntu.edu.tw//handle/246246/11837Four campaigns of GPS measurements have been conducted by the Central Geological Survey since 1995 to investigate the fault surface activity and crustal deformation patterns in southwestern Taiwan. GPS surveys provide the velocity field of the Pingtung-Kaohsiung area in SW Taiwan, in the transition zone from collision to subduction. Station velocities decrease from 42.2 mm/yr in the west to 55.5 mm/yr in the east along azimuths from 247 o to 273 o . In the central and western study area, GPS stations move nearly toward the west. In the Pingtung-Kaohsiung coastal area, the velocity vectors show a counter-clockwise deviation toward the SW, which we explain in terms of lateral extrusion. The transtensional deformation and along-strike southward increase in extensional deformation in southwest Taiwan result from low lateral confining conditions related to the Manila subduction zone as a free boundary or/and the presence of the Peikang High indenter. The GPS vectors indicate that the Chishan Fault is dominated by right-lateral motion with a surface fault slip rate of ~7 mm/yr in a N50 o W direction. The Kaoping Fault bounded in the west side of Pingtung plain is dominated by left-lateral motion with a surface fault slip rate of ~4-8 mm/yr in a N-S direction. The significant right-lateral component of motion of ~24-30 mm/yr can be accommodated along the active structures west of the Chishan Fault, between the coast and the deformation front. The right-lateral and left-lateral structures facilitate the southwestward extrusion. The major Chaochou Fault is a high-angle reverse fault with left-lateral movement. Based on our GPS study, the velocity gradients across this fault are not significant, suggesting that the Chaochou Fault is locked near the surface.application/pdf764334 bytesapplication/pdfzh-TW國立臺灣大學地質科學系暨研究所reporthttp://ntur.lib.ntu.edu.tw/bitstream/246246/11837/1/922116M002004.pdf