Gales: a multiphysics code for volcanic deformation

Ground deformation in volcanic settings can reflect pressurizing/depressurizing subsurface magma bodies, which could have geometries ranging from spheroid-like fluid-filled reservoirs to complex networks of dikes, sills, and crystal mush regions.  Having accurate forward models of deformation is important for resolving magma storage geometries and understanding stress states that influence the stability of volcanic areas and any potential eruption activity. In this regard, the finite element method (FEM) has enjoyed wide popularity due to its robustness and accuracy of results in handling of arbitrary geometries.  

We have developed an open-source hpc multiphysics finite element code Gales for solving a wide variety of PDEs. The code is parallelized using OpenMPI, aimed at multi-node (distributed memory architecture) machines. The software is written in modern C++ and can be used on a single desktop as well as on large clusters. The code offers to do static, quasistatic, and dynamic analysis for linear and non-linear elastic rock deformation in 2D/3D. The software can account for heterogeneous rock properties, real topography, and geometrical complexities associated with multiple magmatic reservoirs, connecting dykes, and volcanic conduits. 

The equations are solved using standard Galerkin FEM. For transient problems, temporal discretization is done using the second-order accurate generalized alpha method. The code has been verified on several test cases covering engineering benchmarking to problems with analytic solutions.

A recent validation exercise on "Drivers of Volcano Deformation", participated by an ample community worldwide, demonstrated Gales as one of the best open-source codes for providing accurate solutions for all exercises, with performance comparable with that of the commercial Comsol software in any individual application.