HR: 1340h
AN: OS53A-0973    [Abstracts]
TI: The possible fault system in northern Taiwan
AU: * Huang, W
EM: winlin2098@hotmail.com
AF: Inst. of Geosciences, Nat. Taiwan Ocean Univ., 2 Pei-Ning Road, Keelung, 202, Taiwan
AU: Chen, C
EM: prochen@moeacgs.gov.tw
AF: Central Geological Survey, Taiwan, 2, Lane 109, Haw-Shin Street, Taipei Shan, 23568, Taiwan
AU: Lee, C
EM: leecs@mail.ntou.edu.tw
AF: Inst. of Geosciences, Nat. Taiwan Ocean Univ., 2 Pei-Ning Road, Keelung, 202, Taiwan
AB: In this study, we have compiled several year studies of the refraction and reflection seismic (Ocean Bottom Seismometer, Multi-Channel Seismic and Chirp Sonar) collected by Taiwan R/V Ocean Research No.2 at northern offshore area of Taiwan. We have analyzed the fault structure system between the land and sea areas to realize the fault and linear structure systems in Big Taipei areas. Moreover, we also compare with the previous study of onshore fault system to adjust the fault location of digital landforms model. Using these integrated new data to understand the relation between the fault and tectonic structure especially in northern offshore Taiwan. It is hope the results of this study may be set as an early warning system for geological hazards. The Chinsan fault is major fault structure of early Miocene in this area. The Kanchiau / Keelung/ Taipei/ Wunzaikeng faults parallel to it, along the NE-SW direction. Because the collision and compression of the Luzon arc, a series of thrust fault system happened in the east of Taiwan , and the deformation were followed. This occurred probably at an early orogeny in Taiwan at the age of Miocene. Late Miocene, the arc-land collision zone migrated southward, the subduction zone under the Ryukyu arc extended to the west, it changed the mountain of northeast Taiwan turning over the subduction direction, and created a series of avalanches in the Okinawa Trough. If this model is acceptable, the fault of north Taiwan is from the compress stress to the extension stress and from the thrust fault to the normal fault. There is no large river system northward to the sea in north Taiwan, the sediment is too less to overlaps the trace of fault activity, and the depth of continental shelf is only about 100 meters, it is easy to be effected by the sea water rise/drop, and created the seabed canyons. The collision continued, the rotation and transverse stress caused the strike slip fault and flower structure. The last fault activity is probably involved with the extension. The Datun Mountains and the Keelung volcano are produced by the extension, as well as the submarine igneous bodies and three of north igneous islands and the Diaoyu islands.
DE: 4200 OCEANOGRAPHY: GENERAL
DE: 4219 Continental shelf and slope processes (3002)
DE: 4243 Marginal and semi-enclosed seas
DE: 8110 Continental tectonics: general (0905)
DE: 8169 Sedimentary basin processes
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting