The continuously increasing power of high-performance computing systems enables the application of full waveform inversion to a growing range of data sets yielding high-resolution images of the subsurface structure. This contribution focusses on methodological and algorithmic advances in Salvus, a comprehensive collection of software packages covering the complete toolchain of time-domain waveform inversion with modules for numerical wave propagation, meshing, inversion, and workflow management. 

Salvus’ waveform propagator is based on a continuous high order finite/spectral element discretization and works on conforming unstructured hypercubic and simplicial meshes in 2 and 3 dimensions. A wide variety of wave propagation physics are implemented (acoustic, elastic, viscoelastic, coupled solid-fluid, poroelastic) and a particular focus of the package is a high level of generality without sacrificing performance (zero-cost abstractions).

We additionally present a meshing toolbox that provides fully automated meshing for common domains in seismology and seismic exploration, including various local refinement schemes to adjust the element sizes to the velocity model. Furthermore, we introduce an automated, interactive, and graph-based workflow framework to steer the inversion procedure. It subdivides full waveform inversion into a sequence of tasks that are orchestrated by the workflow manager, thereby separating the numerical simulation from data processing and model handling. This enables us to automatically adjust the computational resources to the current needs, to distribute and execute tasks on remote clusters, and to foster data provenance and reproducibility.

Several numerical examples ranging from laboratory over regional to planetary scale illustrate the wide range of applications that can be tackled with Salvus.