MAVEPROS: a new open source software to predict mantle elastic properties and build realistic tomographic models

Coupling large-scale geodynamic and seismological modelling appears a promising methodology for the understanding of the Earth’s recent dynamics and present-day structure. So far, the two types of modelling have been mainly conducted separately, and a code capable of linking these two methodologies of investigation is still lacking.

In this contribution I present MAVEPROS, a new open source software that allows both for the modelling of strain-induced mantle fabrics and seismic anisotropy, and for the generation of realistic synthetic tomographic models.

As an input, the software requires the velocity, pressure, temperature (and additionally the fraction of deformation accommodated by dislocation creep) fields (averaged each 100 kyr for typical mantle strain rates) outputted by the large-scale mantle flow models.

The strain-induced mantle fabrics are then modelled with D-Rex (Kaminski et al., 2004, GJI), an open source code that has been parallelized and modified to account for fast computation, combined diffusion-dislocation creep (Faccenda and Capitanio, 2012a, GRL; 2013, Gcubed), LPO of transition zone and lower mantle polycrystalline aggregates, P-T dependence of single crystal elastic tensors (Faccenda, 2014, PEPI), advection and non-steady-state deformation of crystal aggregates in 2D/3D cartesian/spherical grids with basic/staggered velocity nodes (Hu et al., 2017, EPSL), homogeneous sampling of the mantle by implementation of the Deformable PIC method (Samuel, 2018, GJI), apparent anisotropy in layered or crack-bearing rocks estimated with the Differential Effective Medium (DEM) (Sturgeon et al., Gcubed, 2019). The new version of D-Rex can solve for the LPO evolution of 100.000s polycrystalline aggregates of the whole mantle in a few hours, outputting the full elastic tensor of poly-crystalline aggregates as a function of each single crystal orientation, volume fraction and P-T scaled elastic moduli.

The crystal aggregates can then be interpolated in a tomographic grid for either visual inspection of the mantle elastic properties  (such as Vp and Vs isotropic anomalies; radial, azimuthal, Vp and Vs anisotropies; reflected/refracted energy at discontinuities for different incidence angles as imaged by receiver function studies; ), or to generate input files for large-scale synthetic waveform modelling (e.g., SPECFEM3D format; FSTRACK format to calculate SKS splitting (Becker et al., 2006, GJI)).