High-resolution remote sensing data to measure topographic changes in volcanoes: successes, challenges and future perspectives

Quantifying topographic changes in volcanoes provides important information about volcanic deposits and mass-wasting processes, with implications for forecasting volcanic hazards. High-resolution Digital Elevation Models (DEMs) acquired over time are a powerful tool to develop time-series of topographic changes. Here we use EarthDEM/ArcticDEM DEMs, derived from Maxar satellites stereo-optical data, and DEMs derived from bistatic TerraSAR-X/TanDEM-X data to study topographic changes in different volcanoes placed worldwide. These volcanoes experienced different volcanic eruptions, generating a wide range of volcanic deposits and mass-wasting features. The high resolution of these DEMs allowed us to detect many topographic changes not visible with lower resolution DEMs, also in difficult environmental conditions, as long as height changes are ≥0.5-2 m, which is the range of vertical data errors. Pre-eruptive DEMs used to process bistatic data can affect volume estimates, while clouds and artifacts often affect EarthDEM/ArcticDEM. Nevertheless, high-resolution DEMs remain a valuable tool to quantify volcanic deposits and can be combined with other remote sensing data (thermal, InSAR) to better understand the volcanic activity in poorly monitored volcanoes. Acquisition of high resolution DEMs on a more frequent basis could significantly improve our ability to document time-dependent topographic changes at volcanoes worldwide.