Harmony for the solid Earth

Abstract

Spatially-detailed maps of three-dimensional surface displacements and topography change, and their temporal evolution, are essential for understanding and modelling geophysical processes that trigger earthquakes, landslides and volcanic events, and for the assessment of hazards arising from these phenomena. Current SAR missions are sensitive to vertical and east-west motions, but are extremely limited in their sensitivity to north-south motion. In its bistatic configuration the Harmony mission will deliver 3D vectors of surface motion by means of differential repeat-pass InSAR methods. In areas where displacement is predominantly north-south, the ability to systematically measure the third dimension of displacement will reveal motions that have been invisible up until now, and in other areas will enable the resolution of ambiguities in the underlying physical processes that lead to earthquakes, landslides and volcanism. Resolving strain rates in tectonic regions down to 10 nanostrain/year will be a key target for the mission, which will encompass the majority of continental regions that lead to deadly earthquakes. In its cross-track configuration, besides still providing 3D deformation maps, the Harmony mission will deliver time series of topographic change, providing high resolution views of the active processes that reshape the Earth's surface. A key focus will be constraining changes that occur during volcanic eruptions, such as lava flows, dome growth and pyroclastic density flow deposits.