EGU22-11229, updated on 07 Apr 2023
EGU General Assembly 2022
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

The Horizontal Slab Beneath East Asia and Its Subdued Surface Dynamic Response

Bo Zhang1, Shaofeng liu1, Pengfei Ma2, and Michael Gurnis3
Bo Zhang et al.
  • 1China university of Geosciences (Beijing), School of Earth Sciences and Resources, China (
  • 2Taiyuan University of Technology, Department of Earth Science and Engineering
  • 3California Institute of Technology, Seismological Laboratory

The kinematics of plate tectonics, deformation, and dynamic topography are strong indicators of coupling between plates and the mantle. East Asia is characterized by the presence of an unusually large horizontal slab that lies within the mantle transition zone. How this feature evolved and is linked to plate tectonics, deformation, and topography is poorly understood. Here, we show four-dimensional geodynamic modeling results constrained by a new deforming plate reconstruction that fits mantle architecture inferred from seismic tomography. We find that the subducted western Pacific slab was progressively torn by the Philippine Sea plate rotating clockwise during the Miocene and that northwestward mantle flow contributed to shaping the horizontal slab during subduction, leading to dynamic subsidence along the East Asia margin. The rather subdued change in dynamic topography, predicted from those models that fit the horizontal slab in the mantle, is consistent with the variation in residual topography, recorded in the stratigraphy, within only about +/- 200 m over the last 50 Myr during a period of no large marine inundation or retreat. The tectonics and topography of East Asia strongly contrast with those of Southeast Asia and are reflective of slabs ephemerally stagnating in the mantle below East Asia while avalanching into the lower mantle below Southeast Asia.

How to cite: Zhang, B., liu, S., Ma, P., and Gurnis, M.: The Horizontal Slab Beneath East Asia and Its Subdued Surface Dynamic Response, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11229,, 2022.