Volcano geodesy using InSAR in 2020: the past and next decades

The study of volcano deformation has grown significantly through they year 2020 since the development of interferometric synthetic aperture radar (InSAR) in the 1990s. This relatively new data source, which provides evidence of changes in subsurface magma storage and pressure without the need for ground-based equipment, has matured during the past decade. It now provides a means to address previously inaccessible questions and offers input to increasingly complex models of magmatic processes. Here, we review how technological advances in InSAR during 2010-2020 have facilitated our ability to monitor and interpret volcanic processes, primarily through rapid and accurate observations of the changing surfaces at active volcanoes worldwide. Specifically, we examine how current systems achieve excellent resolution in time and space, provide global coverage, and generate products that are easy to use by non-specialists—factors that have often limited the practical study of volcanoes using radar measurements. We also look to the future, offering our perspective about how advancements in technology and data management in the decade to come will increase the value and accessibility of InSAR applied to the geodetic study of volcanoes and monitoring of hazardous volcanic processes. New developments will include the launch of additional satellites by both public space agencies and private companies, as well as implementation of algorithms for exploiting the growing volumes of data. To meet their full potential, these efforts will require coordination between data users and data providers so that the relevant imagery is acquired, made available to volcanologists in a timely fashion, and utilized to assess and mitigate volcanic hazards.