New Mantle Convection Models Constrained by Seismic Tomography Data

Abstract

AbstractIt is supposed that the heterogeneity of the mantle indicated by seismic tomography data is caused by thermal convection. In this case the speed heterogeneity of seismic waves can be transformed to density (or temperature) anomalies. By taking account of the three thermodynamic equations of fluid and considering the effects of nonliner terms in these equations, the density anomalies are regarded as inner loads to drive the mantle convection in our model. The mantle convection patterns with different Rayleigh numbers up to 106 are computed by using the seismic tomography model SH12WM13. The results show that the mantle flow patterns depend on not only the seismic tomography data set, but also the dynamic frame of the mantle and its response function restricted by thermodynamic parameters and boundary conditions. There are complex flow patterns in computed models when the Rayleigh number is going to be higher. It is suggested that regional layer shape convection and multilayer ‐like convection may exist in the Earth's mantle.