Complex Upper Mantle Flow Beneath the Southern Korean Peninsula Constrained by Shear Wave Splitting and Numerical Mantle Convection Simulation
Description:
Seismic anisotropy in the upper mantle, which can be developed by the alignment of anisotropic minerals, such as olivine, provides a means for indirectly analyzing mantle dynamics, including asthenospheric mantle flow. Seismic anisotropy beneath the southern Korean Peninsula (SKP) was measured by shear wave splitting analyses and the upper mantle flow was simulated through numerical mantle convection modeling. The SKP is located at the eastern margin of the Eurasian plate. Subduction boundaries between the Eurasian, Pacific, and Philippine Sea plates are located to the east of the SKP. A significant lateral variation in lithospheric thickness within the SKP has been reported, ranging from ~80 km in the east to ~130 km in the southwest across a lateral distance of ~200 km, implying the potential for a small-scale complex mantle flow driven by a sharp lithospheric thickness gradient. The fast direction of seismic anisotropy in the SKP can be separated into two groups: N-S direction dominant in the east and NW-SE direction dominant in the southwest. The deflected pattern around the southwest SKP was observed and interpreted to reflect asthenospheric mantle flow deflected around the thicker lithosphere.
In the mantle convection modeling, a horizontal mantle flow was initially driven by imposing a horizontal temperature gradient in the model domain. Similar to seismic anisotropy, the simulated mantle flow calculated with realistic lithospheric thickness variations around the SKP was also separated into two groups. Notably, significant deflection in asthenosphere mantle flow was simulated at the shallow depth (~100 km) around the thicker lithosphere in the southwestern SKP, whose pattern was roughly consistent with the observed seismic anisotropy. Our results showed that complex asthenospheric mantle flow in NE Asia can be developed by interaction between background mantle flow with laterally and vertically small-scale variations in lithospheric thickness at the continental margin.
Session: Earth’s Structure from the Crust to the Core [Poster Session]
Type: Poster
Date: 5/2/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Kyeongjun
Student Presenter: Yes
Invited Presentation:
Authors
Kyeongjun Jo Presenting Author jkyeongjun@gmail.com Korea University |
Jung-Hun Song wjdgns230@gmail.com Seoul National University |
Seongryong Kim Corresponding Author seongryongkim@korea.ac.kr Korea University |
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Complex Upper Mantle Flow Beneath the Southern Korean Peninsula Constrained by Shear Wave Splitting and Numerical Mantle Convection Simulation
Category
Earth’s Structure from the Crust to the Core