EGU2020-6466, updated on 10 Jul 2021
https://doi.org/10.5194/egusphere-egu2020-6466
EGU General Assembly 2020
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Anisotropic upper mantle structures in northeast Asia from Bayesian inversions of ambient noise data

Sang-Jun Lee1, Seongryong Kim2, and Junkee Rhie1
Sang-Jun Lee et al.
  • 1School of Earth and Environmental Sciences, Seoul National University, Seoul, Korea, Republic of (stonbear@snu.ac.kr)
  • 2Department of Geological Sciences, Chungnam National University, Daejeon, Korea, Republic of

The northeast Asia region exhibits complex tectonic settings caused by interactions between Eurasian, Pacific, and Philippine Sea plates. Distributed extensional basins, intraplate volcanoes and other heterogeneous features in the region marked results of the tectonic processes, and their mechanisms related to mantle dynamics can be well understood by estimating radial anisotropy in the lithospherie and asthenospherie. We constructed a three-dimensional radial anisotropy model in northeast Asia using hierarchical and transdimensional Bayesian joint inversion techniques with different types of dispersion data up to the depth of the upper mantle (~ 160 km). Thick and deep layers with positive radial anisotropy (VSH > VSV) were commonly found at depths between 70 and 150 km beneath the continental regions. On the other hand, depths and sizes of layers with positive radial anisotropy become shallower and thinner (30 ~ 60 km) respectively beneath regions where experienced the Cenozoic extension. These variations in positive radial anisotropy for different tectonic regions can be understood with the context of extensional geodynamic processes in back arc basins within the East Sea (Japan Sea). Interestingly, the most predominant positive radial anisotropy is imaged along areas with large gradient of the litheosphere-asthnosphere boundary beneath intraplate volcanoes. These observations favor the mechanism of edge-driven convection caused by the difference in lithosphere thickness and localized sublithospheric lateral flow from the continental region to back arc basins.

How to cite: Lee, S.-J., Kim, S., and Rhie, J.: Anisotropic upper mantle structures in northeast Asia from Bayesian inversions of ambient noise data, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6466, https://doi.org/10.5194/egusphere-egu2020-6466, 2020.

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