The low-velocity layer at the depth of 620 km beneath Northeast China  

作　　者：SHEN XuZhang ZHOU HuiLan 

机构地区：[1]Laboratory of Computational Geodynamics, Graduate University of the Chinese Academy of Sciences, Beijing 100049, China [2]Lanzhou Institute of Seismology, China Earthquake Administration, Lanzhou 730000, China

出　　处：《Chinese Science Bulletin》2009年第17期3067-3075,共9页

基　　金：Supported by the National Natural Science Foundation of China (Grant Nos. 40574024 and 40374009)

摘　　要：Based on the 3-D Earth model, the common convert points-phase weighted stacks (CCP-PWS) migra- tion method is used to image the upper mantle discontinuities beneath Northeast China (longitude 120°―132°; latitude 38°―40°) with 802 observed receiver functions. Teleseismic records are obtained from 4 stations belonging to CCDSN and 19 stations belonging to PASSCAL. A low-velocity layer has been detected at the depth of 620 km. This low-velocity layer rises to 600 km in the east of the study region close to the subducted slab. We consider that this low-velocity layer might be the accumulated oceanic crustal material delaminated from the western Pacific subducted slab. Additionally, we detect the obvious depression of 660 km discontinuity which was attributed to the interaction between the upper mantle and subducted slab. The maximum depth of 660 km discontinuity approaches 700 km, and 660 km discontinuity splits into multiple discontinuities in the northeast of the study region.Based on the 3-D Earth model, the common convert points-phase weighted stacks （CCP-PWS） migration method is used to image the upper mantle discontinuities beneath Northeast China （longitude 120°―132°; latitude 38°―40°） with 802 observed receiver functions. Teleseismic records are obtained from 4 stations belonging to CCDSN and 19 stations belonging to PASSCAL. A low-velocity layer has been detected at the depth of 620 km. This low-velocity layer rises to 600 km in the east of the study region close to the subducted slab. We consider that this low-velocity layer might be the accumulated oceanic crustal material delaminated from the western Pacific subducted slab. Additionally, we detect the obvious depression of 660 km discontinuity which was attributed to the interaction between the upper mantle and subducted slab. The maximum depth of 660 km discontinuity approaches 700 km, and 660 km discontinuity splits into multiple discontinuities in the northeast of the study region.

关 键 词：中国东北 低速层 公里 PASSCAL 地幔间断面 地球模型 迁移方法 物质积累 

分 类 号：P315.31[天文地球—地震学] K264[天文地球—固体地球物理学]