Drivers of Volcano Deformation (DVD) validation and verification exercises: Phase 1

Volcano geodesy typically requires the synthesis of ground deformation models with observational data. A wide variety of volcano deformation models have been developed, from simple point source models to sophisticated numerical approaches that attempt to account for realistic topographies, complex source geometries and heterogeneous geologic structure. A wide variety of inverse methods are also combined with these models to characterize the volcanic sources from the observed data. However, to date there has been no comprehensive attempt to intercompare volcano deformation models and inversion results, or to establish baseline standards of reproducibility. The Drivers of Volcano Deformation (DVD) exercises provide a community-driven framework to accomplish these goals with a series of exercises for verification - quantitative comparison of forward model outputs, and validation - comparison of inversion results from synthetic data. The forward model exercises begin with a spherical reservoir in a homogeneous half-space, for which an exact solution exists, then introduce topography, more complex source geometries, and heterogeneous elastic properties. The inversion exercises provide synthetic GNSS and InSAR datasets for spherical reservoirs in elastic half-spaces with varying noise, and assess the consistency and uniqueness with which reservoir location, volume change, radius and pressurization can be inverted. The forward models comparison resulted in multiple bugs being fixed in commonly used solutions. The variability of inversion results emphasizes the importance of model choice, inverse methods, and uncertainty quantification. The Drivers of Volcano Deformation exercises are planned to evolve with additional phases that will test more complex forward models and inverse problems.
The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)