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Mantle Transition Zone Structure Beneath Northeast Asia From 2‐D Triplicated Waveform Modeling: Implication for a Segmented Stagnant Slab

Lai, Yujing and Chen, Ling and Wang, Tao and Zhan, Zhongwen (2019) Mantle Transition Zone Structure Beneath Northeast Asia From 2‐D Triplicated Waveform Modeling: Implication for a Segmented Stagnant Slab. Journal of Geophysical Research. Solid Earth, 124 (2). pp. 1871-1888. ISSN 2169-9313. https://resolver.caltech.edu/CaltechAUTHORS:20190410-161048767

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Abstract

The structure of the mantle transition zone (MTZ) in subduction zones is essential for understanding subduction dynamics in the deep mantle and its surface responses. We constructed the P (V_p) and SH velocity (V_s) structure images of the MTZ beneath Northeast Asia based on two‐dimensional (2‐D) triplicated waveform modeling. In the upper MTZ, a normal V_p but 2.5% low V_s layer compared with IASP91 are required by the triplication data. In the lower MTZ, our results show a relatively higher‐velocity layer (+2% V_p and −0.5% V_s compared to IASP91) with a thickness of ~140 km and length of ~1,200 km atop the 660‐km discontinuity. Taking this anomaly as the stagnant slab and considering the plate convergence rate of 7–10 cm/year in the western Pacific region during the late Cenozoic, we deduced that the stagnant slab has a subduction age of less than 30 Ma. This suggests that the observed stagnancy of the slab in the MTZ beneath Northeast Asia may have occurred no earlier than the Early Oligocene. From the constraints derived individually on V_p and V_s structures, high V_p/V_s ratios are obtained for the entire MTZ beneath Northeast Asia, which may imply a water‐rich and/or carbonated environment. Within the overall higher‐velocity stagnant slab, a low‐velocity anomaly was further detected, with a width of ~150 km, V_p and V_s reductions of 1% and 3% relative to IASP91. Such a gap may have provided a passage for hot deep mantle materials to penetrate through the thick slab and feed the Changbaishan volcano.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1029/2018jb016642DOIArticle
ORCID:
AuthorORCID
Lai, Yujing0000-0002-5121-2869
Chen, Ling0000-0001-7170-5954
Wang, Tao0000-0002-4898-4892
Zhan, Zhongwen0000-0002-5586-2607
Additional Information:© 2019 American Geophysical Union. Received 5 SEP 2018; Accepted 18 JAN 2019; Accepted article online 25 JAN 2019; Published online 16 FEB 2019. Waveform data for this study are provided by Data Management Centre of China National Seismic Network at Institute of Geophysics (http://www.seisdmc.ac.cn/, in Chinese; SEISDMC, doi:10.11998/SeisDmc/SN; Zheng et al., 2010), China Earthquake Networks Center and SN, SX, QH, NX, NM, GS, HB, HE, BJ, CC, BU, TJ, LN Seismic Networks, China Earthquake Administration. Thanks to Youcai Tang, Yoshio Fukao, Masayuki Obayashi, and Nathan Simmons for sharing their tomographic model. Discussions with Gaoshan Guo, Xu Wang, Tingting Yang, and Xiaozhuo Wei helped a lot in writing this paper. Ling Chen thanks COFFICE 422 at IGGCAS for the helpful discussions. We thank Computer Simulation Lab, IGGCAS, SeismoCluster in IGG, Nanjing University, and National Supercomputer Center in Guangzhou for the computing resources. GMT software (Wessel & Smith, 1998) and matplotlib (Hunter et al., 2007) were used in making part of the figures. We thank Editor Martha Savage and two anonymous reviewers for the constructive comments that helped to improve this paper. This research is supported by the National Natural Science Foundation of China (grant 41688103), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA20070302), and International Partnership Program of the Chinese Academy of Sciences (GJHZ1776). Zhongwen Zhan is partially supported by National Science Foundation grant 1722879.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
National Natural Science Foundation of China41688103
Chinese Academy of SciencesXDA20070302
Chinese Academy of SciencesGJHZ1776
NSFEAR-1722879
Subject Keywords:MTZ structure; Northeast Asia; two‐dimensional triplicated waveform modeling
Issue or Number:2
Record Number:CaltechAUTHORS:20190410-161048767
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20190410-161048767
Official Citation:Lai, Y., Chen, L., Wang, T., & Zhan, Z. (2019). Mantle transition zone structure beneath Northeast Asia from 2‐D triplicated waveform modeling: Implication for a segmented stagnant slab. Journal of Geophysical Research: Solid Earth, 124, 1871–1888. https://doi.org/10.1029/2018JB016642
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:94649
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:10 Apr 2019 23:40
Last Modified:03 Oct 2019 21:05

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