Articles | Volume 9, issue 2
Solid Earth, 9, 267–294, 2018
Solid Earth, 9, 267–294, 2018

Method article 19 Mar 2018

Method article | 19 Mar 2018

Nonlinear viscoplasticity in ASPECT: benchmarking and applications to subduction

Anne Glerum1,2, Cedric Thieulot1, Menno Fraters1, Constantijn Blom1, and Wim Spakman1,3 Anne Glerum et al.
  • 1Earth Sciences, Utrecht University, Utrecht, the Netherlands
  • 2Geodynamic Modelling, GFZ German Research Centre for Geosciences, Potsdam, Germany
  • 3Centre of Earth Evolution and Dynamics (CEED), University of Oslo, 0316 Oslo, Norway

Abstract. ASPECT (Advanced Solver for Problems in Earth's ConvecTion) is a massively parallel finite element code originally designed for modeling thermal convection in the mantle with a Newtonian rheology. The code is characterized by modern numerical methods, high-performance parallelism and extensibility. This last characteristic is illustrated in this work: we have extended the use of ASPECT from global thermal convection modeling to upper-mantle-scale applications of subduction.

Subduction modeling generally requires the tracking of multiple materials with different properties and with nonlinear viscous and viscoplastic rheologies. To this end, we implemented a frictional plasticity criterion that is combined with a viscous diffusion and dislocation creep rheology. Because ASPECT uses compositional fields to represent different materials, all material parameters are made dependent on a user-specified number of fields.

The goal of this paper is primarily to describe and verify our implementations of complex, multi-material rheology by reproducing the results of four well-known two-dimensional benchmarks: the indentor benchmark, the brick experiment, the sandbox experiment and the slab detachment benchmark. Furthermore, we aim to provide hands-on examples for prospective users by demonstrating the use of multi-material viscoplasticity with three-dimensional, thermomechanical models of oceanic subduction, putting ASPECT on the map as a community code for high-resolution, nonlinear rheology subduction modeling.

Short summary
A nonlinear viscoplastic rheology is implemented and benchmarked in the ASPECT software, allowing for the modeling of lithospheric deformation. We showcase the new functionality with a four-dimensional model of thermomechanically coupled subduction.