Sentinel-1 Monitoring Of Santorini Volcano Post-Unrest State

At the beginning of 2011 Santorini volcano underwent a volcanic unrest, accompanied by an increase of the micro-seismic activity. The unrest that lasted for over a year, demonstrated substantial amounts of uplift, justifying the volcanic origin of the activity. The continuation of the deformation monitoring after the unrest event was deemed necessary, in order to validate the post-unrest state of the volcano and to recognize potential ground deformation signals. The Copernicus Sentinel-1 mission is profoundly promising towards this direction, due to its systematic acquisition and short revisit. A multi-temporal SAR interferometric analysis was deliberated in a way to avoid significant phase changes and to retain high coherence. In this paper, DInSAR analysis was applied over Santorini to retrieve the actual deformation state of the volcano during the repose period 2014-2017. The results indicate subsidence rates on Nea Kameni of about 8-9 mm/yr, implying a gradual deflation of the magma chamber, while the rest of the area appears almost stable with negligible deformation.