- 期刊
- OpenAccess
A Three-Dimensional Vp Model of the Southeastern Taiwan Area and Its Tectonic Implications
臺灣東南地區三維P波速度模型及其在地體構造上之意義
並列摘要
The Taitung Canyon originates at the southern end of the Longitudinal Valley.It runs southward along the axis of the Taitung Trough.Thecanyon turns eastward into the Huatung Basin,after crossing the Luzonarc between the volcanic islands of Lanyu and Lutao.It then flows northeastward for about 170km and merges with the Hualien Canyon near theRyukyu Trench,thus forming the largest canyon in the Huatung Basin.High resolution bathymetric data,and several multi-channel seismic profiles are used to describe the structural fabric in the vicinity of the TaitungCanyon and the factors controlling its path within the Huatung Basin.Crossing the eastern slope of the Lanyu-Lutao volcanic ridge,the head of theTaitung Canyon is fan shaped and its entrenchment rapidly increasesdownslope.Throughout the canyon's upper and central portions,the channel depth ranges from 300 to 500m with respect to the surrounding seafloor. The canyon's levees are generally asymmetric and turbidite overbankdeposits are observed.Then,a basement high,trending parallel to the GaguaRidge,forces the path of the Taitung Canyon to turn 90°toward the northwest. As the canyon reaches the Ryukyu Trench,the width of the mainchannel has decreased from 14 km near the Luzon arc,to less than 200m atthe outer-slope of the Ryukyu Trench.The importance of structural controls, such as basement highs and faulting,on the canyon's developmentare examined.Thus,the existence of a strike-slip fault system,affecting theoceanic basement in the Huatung Basin,and its role in controlling the pathof the canyon are discussed.