EGU24-18579, updated on 11 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Complex subduction and mantle dynamics induced by along-strike variations in overriding plate structure

Pedro José Gea Jódar1, Ana M. Negredo3, Flor de Lis Mancilla1, Jeroen van Hunen4, and Magali Billen5
Pedro José Gea Jódar et al.
  • 1Andalusian Institute of Geophysics and Prevention of Seismic Disasters, University of Granada, Granada, Spain
  • 3Institute of Geosciences IGEO (CSIC, UCM), Madrid, Spain
  • 4Department of Earth Sciences, Durham University, DH1 3LE Durham, UK
  • 5Department of Earth and Planetary Sciences, UC Davis, Davis, UnitedStates

Subduction zones are intrinsically three-dimensional and present a huge variability in observables along the trench, such as deformation style of the overriding plate, trench velocity, slab depth and mantle flow patterns. Geodynamic models commonly rely on factors such as external mantle flow and/or along-strike variations in the properties of subducting slabs to account for these variations in the trench-parallel direction, often ignoring the role of the overriding plate, which has been proven to strongly affect subduction dynamics. In this work, we investigate through self-consistent 3D subduction models how along-strike variations in the overriding plate structure can induce along-strike variations in subduction dynamics and mantle flow. Our results show that variations of the overriding plate thickness along the trench-parallel direction result in large along-strike variations of the trench retreat velocities, leading to highly arcuated trenches. This difference in trench retreat velocities along the trench induce complex mantle flow patterns, with the toroidal flow cells that surround the slab converging below the thin part of the overriding plate. Due to this complex mantle flow, regions of maximum localised extension are found within the thin portion of the overriding plate. Overall, our results contribute to a better understanding of seismic anisotropy observations at subduction zones on Earth.

How to cite: Gea Jódar, P. J., Negredo, A. M., Mancilla, F. D. L., van Hunen, J., and Billen, M.: Complex subduction and mantle dynamics induced by along-strike variations in overriding plate structure, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18579,, 2024.