NEOTECTONIC FEATURES AND MOVEMENT IN THE EAST CHINA SEA

Since late Pliocene, neotectonic movement in the East China Sea has been intensified, and the most obvious features of the neotectonic movement include faults, folds, magmatic intrusion and eruption, seafloor hydrothermal activities, and coastal changes, etc. The neotectonic movement is characteriged by vertical large-scale block-faulting, in an oscillating and episodic manner. Regional difference of neotectonic movement is apparent and shows continuity to cerlain extent in some areas. Meantime, the neotectonic movement occurs in NE(or NEE)~NNE direction along the continent margin, and includes two parts:the eastern belt along the Okinawa Trough and the western belt along the western border of the East China Sea shelf, which extends from-Shanghai, to Zhejiang, Fujian,and Guangdong offshore regions. A tranquil zone of neotectonic movement occurs between the two belts. Neotectonic movement is mainly characterized by faulting, seismic activities, and large-amplitude block-faulting in the western belt; but more intensified in the eastern belt. It includes not only faulting, frequently earthgualce activities, and large-amplitude block-faulting, but also folding, large-scale intrusion and eruption of magmatic rocks, and seafloor hydrothermal activities. Intensive neotectonic movement in the East China Sea owes its origin to the intensitied trough extension in Quaternary, as one of the features of the active subduction of the Pacitic plate.