Years of Sentinel-1 data exploitation to monitor volcanic and seismic areas through DInSAR techniques

Abstract

Since 2014, the Sentinel-1 satellite constellation has provided a huge amount of Synthetic Aperture Radar (SAR) data across the Earth with an unprecedent continuous and high acquisition rate. These characteristics, together with the free and open access Copernicus data policy, have made possible the development of operational services aimed at monitoring the millimetric displacements of Earth surface, with particular reference to volcanic and seismic phenomena. The services are based on the Differential SAR Interferometry (DInSAR) technique, which permits measuring the crustal displacements from a multi-temporal set of SAR data acquisitions. The services herein presented are part of the tasks of the Institute for the Electromagnetic Sensing of the Environment of National Research Council of Italy (IREA-CNR) to support the Italian Department of Civil Protection (DPC) for volcanoes and seismic areas monitoring. One of the implemented services starts from the occurrence of an earthquake, once published in the main global seismic catalogues, and generates the relevant DInSAR co-seismic displacement maps with the available Sentinel-1 data. This tool is fully operative and generates products dating back to 2015, thus allowing us to investigate the ground displacement associated to more than 600 earthquakes. More recently, the tool has been extended to provide not only the measure of the displacement, but also a speditive model of the seismic source and it is under development a machine learning based solution to further extend the retrieved information. All the generated products are freely available to the scientific community through the European Plate Observing System Research Infrastructure (EPOS-RI). A second service is dedicated to volcano ground displacement monitoring. In this case, every time a new SAR data in the Sentinel-1 catalogues is available over a monitored volcano, the DInSAR processing, based on the Parallel Small BAseline Subset (P-SBAS) approach, starts and allows updating the ground displacement time series for both the ascending and descending passes. The so-retrieved Line of Sight (LOS) measurements are then combined to compute the Vertical and East-West components of the computed displacements, which are straightforwardly understandable by most of the end users. This service is currently running for the main active Italian volcanoes (Campi Flegrei caldera, Mt. Vesuvius, Ischia, Mt. Etna, Stromboli and Vulcano), making us able to continuously follow the temporal evolution of the ground displacement since 2015. Are currently under development automatic and semi-automatic techniques to investigate the detected ground displacements.   This work is supported by: the CNR-IREA and Italian DPC agreement; the EPOS-RI, including the one obtained through the EPOS-Italia JRU; the European Union - NextGeneratonEU through the projects: NRRP - MEET (Monitoring Earth's Evolution and Tectonics); ICSC - CN-HPC - PNRR M4C2 Investimento 1.4 - CN00000013; GeoSciences IR - PNRR M4C2 Investimento 3.1 - IR0000037; Sustainable Mobility Center - MOST - PNRR M4C2 Investimento 1.4 - CN00000023.