Sensitivity of horizontal surface deformation to mantle dynamics from 3D instantaneous dynamics modeling of the eastern Mediterranean region

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Authors

Anne C Glerum , Wim Spakman , Douwe J.J. van Hinsbergen, Cedric Thieulot , Casper Pranger

Abstract

Geodetically estimated surface motions contain contributions to crustal deformation from coupled geodynamic processes active at all spatial scales and constitute key data for lithosphere dynamics research. Data interpretation methods should therefore account for the full range of possible processes, otherwise risking misinterpretation of data signal and incorrect estimation of lithosphere rheology, stress, or deformation fields. Here we explore the sensitivity of surface deformation to sub-lithospheric processes such as viscous plate-mantle and slab-mantle coupling, variations in slab pull, and buoyancy-driven mantle flow. To this end, we perform 3D instantaneous-dynamics numerical modelling of an elaborately structured compressible crust-mantle system designed for the Eastern Mediterranean Aegean-Anatolian region. We first determine a reference model driven by the absolute motions of the major plates, regional slab pull, a 3D mantle buoyancy field, and modulated by plate boundary coupling and mantle viscosity. The RMS motion data fit of ~5.9 mm/yr of predicted and observed Aegean-Anatolian horizontal surface motions demonstrates that the bulk amplitude of surface motion can be explained by these combined mantle processes. Next, by systematically perturbing reference model features, we assess the crustal sensitivity to each geodynamic driver and to mantle rheology. We find significant changes in crustal velocity gradient amplitudes, often between 10% and 40% of the reference model, with slab morphology effects of up to 93%. This demonstrates the key importance of carefully accounting for each process in modelling lithosphere dynamics. For the Aegean-Anatolia region, we present geodynamic evidence that the Aegean slab pull is the primary driver of the crustal motion field, as was previously suggested from kinematic analysis.

DOI

https://doi.org/10.31223/X5FW59

Subjects

Geophysics and Seismology, Tectonics and Structure

Keywords

Geodynamics, numerical modeling, mantle dynamics, Eastern Mediterranean, Aegean subduction, horizontal surface motions

Dates

Published: 2021-11-29 12:39

License

CC BY Attribution 4.0 International

Additional Metadata

Data Availability (Reason not available):
Reason not available: The source code and input files used in this study have not been stored in an archive facility yet. They will be before submission of the manuscript to a peer-reviewed journal.

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