The Italian Space Agency (ASI) and the Earth Observation & Geospatial Application Lab (EO.Lab) of the Aristotle University of Thessaloniki (AUTh) join forces to undertake a collaboration of high technical and scientific value, aimed to an enhanced satellite radar monitoring of Santorini volcano, one of Europe’s most active volcanic systems.

This collaboration is in the framework a COSMO-SkyMed project between ASI and AUTh, whose main scientific objective is to characterise the state of activity of the volcano based on the processing and analysis of high spatial resolution Synthetic Aperture Radar (SAR) images, collected by ASI’s COSMO-SkyMed constellation.

This collaboration is of critical importance, as it comes during a period of renewed activity at Santorini. In particular, signs of unrest were detected in the northern part of the caldera beginning in July 2024, with deformation evolving through the end of the year. This activity was followed by additional ground deformation signals linked to the broader Anydros tectono-volcanic activity in February 2025.

Thanks to the provision of COSMO-SkyMed images, Santorini volcano is monitored through regular and systematic satellite observations, and it will be so for a period of at least two years. To this scope, ASI has increased the temporal frequency with which COSMO-SkyMed images are collected. Consequentially, on a regular basis, AUTh updates the interferometric processing using InSAR techniques and produce deformation maps.

The initial results underscore the added value achieved with COSMO-SkyMed. By shortening the temporal distance between two consecutive observations, it is possible to increase the likelihood of detecting, at an early stage, signals of new deformation or changes of those that are already occurring. COSMO-SkyMed observations therefore complement those that AUTh and the Institute for the Study and Monitoring of Santorini Volcano (ISMOSAV) are currently performing using Copernicus Sentinel-1 images.

In detail, the figure shows the results obtained from the InSAR processing of 35 COSMO-SkyMed images collected between April and December 2024. The blue-coloured areas highlight ground deformation towards the line of sight of the satellite (uplift areas), while the red-yellow areas highlight ground deformation away from the line of sight of the satellite (subsidence areas).

The first results were presented during the last meeting of the Committee on Earth Observation Satellites (CEOS) Working Group on Disasters (WGD) in Catania and will be further improved, after new InSAR processing and interpretation are performed jointly by ASI and AUTh. The COSMO-SkyMed results will be interpreted via integration with measurements collected through ground-based networks maintained by ISMOSAV.

The ASI – AUTh joint initiative underlines the importance of international cooperation in volcano hazard monitoring and associated risk based on Earth Observation data, to the benefit of both scientific understanding and public safety.