A global,spherical,finite-element model for postseismic deformation using ABAQUS

We present a finite-element model of postseismic solid Earth deformation built in the software package ABAQUS (version 2018). The model is global and spherical, and includes self-gravitation and is built for the purpose of calculating postseismic deformation in the far-field (> ~ 300 km) of major earthquakes. An earthquake is simulated by prescribing slip on a fault plane in the mesh and the model relaxes under the resulting change in stress. Both linear Maxwell and biviscous (Burgers) rheological models have been implemented and the model can be easily adapted to include different rheological models and lateral variations in Earth structure, a particular advantage over existing models. We benchmark the model against an analytical coseismic solution and an existing open-source postseismic model, demonstrating good agreement for all fault geometries tested. Due to the inclusion of self-gravity the model has the potential for predicting deformation in response to multiple sources of stress change, for example, changing ice thickness in tectonically active regions.