The Subduction Structure Beneath the New Britain Island Arc and the Adjacent Region from Double-Difference Tomography  

作　　者：ZHANG Hao GONG Wei XING Junhui XU Chong LI Chaoyang 

机构地区：[1]Key Laboratory of Submarine Geosciences and Prospecting Techniques,Ministry of Education,and College of Marine Geosciences,Ocean University of China,Qingdao 266100,China [2]Laboratory for Marine Mineral Resources,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China [3]College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266590,China

出　　处：《Journal of Ocean University of China》2023年第1期107-118,共12页中国海洋大学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.41906048 and 91858215).

摘　　要：We applied double-difference tomography to relocate seismic events and determine the lithospheric velocity structure beneath the New Britain Island arc and the South Bismarck Sea Basin,based on the local P wave arrival time dataset collected by the International Seismological Centre.Results of the seismic relocation and velocity inversion show that the subduction of Solomon Sea Plate along the New Britain Trench is spatially different above 150 km,and the subduction angle of the slab on the west side is higher than that on the east side.The relocated earthquakes also show that there are double seismic zones at the depths of about 30–90km beneath the New Britain Island Arc.The velocity structure shows that the dehydration of the subducting slab caused the low-velocity anomalies in mantle wedge above the slab,which are associated with the magmatic activities around the New Guinea-New Britain Island arc.Moreover,it shows that there is another low-velocity anomaly zone beneath the Bismarck mid-oceanic ridge with spatial variation.Beneath the west of the Bismarck mid-oceanic ridge,the low-velocity anomaly is weakly connected to the subducted Solomon Sea slab.Conversely,the low-velocity anomaly beneath the Manus Sea Basin is highly intertwined to the subducting slab and its mantle wedge,indicating that the subduction of the Solomon Sea Plate might be a key deep dynamic factor that drives the spreading of the Manus Sea Basin and the separation of the Bismarck Plate.

关 键 词：New Britain Trench Bismarck Sea Basin Manus Sea Basin double-difference tomography 

分 类 号：P736.1[天文地球—海洋地质]