第九届青年地学论坛

The deep structure of the East China Sea (ECS) area is influenced by a variety of factors, primarily the Philippine Sea Plate, the Pacific Plate, the Eurasian Plate and remote effect of the Indian Plate. It is a significant place to study the geodynamics and plate tectonics owing to the unique trench-arc-basin system. However, more detailed and deeper structural information beneath the main tectonic units in this area is still ambiguous. In this work, we determine high-resolution 3-D tomographic images in the ECS area to provide more information and constraints on the deeper structure. Our tomographic results clearly reveal the high-V anomalies in the Zhemin Volcanic Belt (ZMVB) and the Diaoyu Island Uplift-Fold Belt (DB), which are both related to the magmatic activities originated from the tectonic genesis. The Continental Shelf Basin (CSB) presents the low-V anomalies, which may be affected by many elements. We infer these are mainly derived from sediments, faults, properties of rocks and plate tectonic movement. High- and low-V anomalies are shown in block form in the Okinawa Trough, which may be closely associated with the compact lithosphere caused by magma intrusion and consolidation and the mantle upwelling induced by the dehydration and subduction of slab, respectively. In addition, we also find most big earthquakes (M ≥ 7) in this area since the 17^th century occurred around the boundary of the high- and low-V anomalies or in the high-V anomalies.        
 

层析成像,东海,深部结构,大地震