3-D Variable Viscosity Mantle Convection Constrained by Seismic Wave Velocity and Its Geodynamic Implications

Mantle convection model with a 3‐D laterally variable viscosity constrained by seismic wave velocity is developed and its corresponding solution is presented in this paper. The poloidal and toroidal convection patterns are presented at Rayleigh number Ra = 106 under two kinds of boundary conditions,...

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Bibliographic Details
Published in:Chinese journal of geophysics 2006-09, Vol.49 (5), p.1230-1244
Main Authors: ZHU, Tao, MA, Zong‐Jin, FENG, Rui
Format: Article
Language:English
Subjects:
3-D variable viscosity
Surface tectonics
Toroidal convection
Variable viscosity model
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Summary:Mantle convection model with a 3‐D laterally variable viscosity constrained by seismic wave velocity is developed and its corresponding solution is presented in this paper. The poloidal and toroidal convection patterns are presented at Rayleigh number Ra = 106 under two kinds of boundary conditions, respectively, which are helpful to further recognize and understand the behavior of mass motion in the mantle and the deep dynamic process of surface tectonic motion. Our results indicate that not only the poloidal convection patterns in uppermost mantle have good correlations to surface tectonic motion, but also the toroidal ones reveal important information of their horizontal motion and rotation for the first time. There is a SEE‐NWW strong convection zone close to the equator in toroidal convection patterns, which probably correlates with the large‐scale shear zone near the equator and is the deep dynamic background of strong earthquake occurrence in this zone. The opposite rotating large‐scale convection rolls in the Southern and Northern hemispheres suggest that maybe there is differential rotation between them.
ISSN:0898-9591
2326-0440
DOI:10.1002/cjg2.948