Multi-Sensor SAR Geodetic Imaging and Modelling of Santorini Volcano Post-Unrest Response

• Published in: Remote sensing (Basel, Switzerland) Vol. 11; no. 3; p. 259
• Main Authors: Papageorgiou, Elena, Foumelis, Michael, Trasatti, Elisa, Ventura, Guido, Raucoules, Daniel, Mouratidis, Antonios
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.01.2019; MDPI
• Subjects: Applied geology; Calderas; Computer simulation; Deformation; Degassing; Earth Sciences; Earthquakes; Interferometric synthetic aperture radar; Interferometry; inversion modelling; Magma; Modelling; post-unrest deflation; Radarsat; Remote sensing; Santorini; SAR interferometry; Sciences of the Universe; Subsidence; Superposition (mathematics); Time series; Volcanic activity; volcano deformation; Volcanoes; Greece; Italy; Santorini; SCATTERER INTERFEROMETRY; CALDERA; SAR interferometry; RESOLUTION; post-unrest deflation; NEIGHBORHOOD ALGORITHM; DEFORMATION; UPLIFT; SUBSIDENCE; GEOPHYSICAL INVERSION; VOLATILES; volcano deformation; PERMANENT SCATTERERS; inversion modelling; Santorini
• ISSN: 2072-4292; 2072-4292
• DOI: 10.3390/rs11030259

Volcanic history of Santorini over recent years records a seismo-volcanic unrest in 2011–12 with a non-eruptive behavior. The volcano deformation state following the unrest was investigated through multi-sensor Synthetic Aperture Radar Interferometry (InSAR) time series. We focused on the analysis of Copernicus Sentinel-1, Radarsat-2 and TerraSAR-X Multi-temporal SAR Interferometric (MT-InSAR) results, for the post-unrest period 2012–17. Data from multiple Sentinel-1 tracks and acquisition geometries were used to constrain the E-W and vertical components of the deformation field along with their evolution in time. The interpretation of the InSAR observations and modelling provided insights on the post-unrest deformation pattern of the volcano, allowing the further re-evaluation of the unrest event. The increase of subsidence rates on Nea Kameni, in accordance with the observed change of the spatial deformation pattern, compared to the pre-unrest period, suggests the superimposition of various deformation sources. Best-fitting inversion results indicate two deflation sources located at southwestern Nea Kameni at 1 km depth, and in the northern intra-caldera area at 2 km depth. A northern sill-like source interprets the post-unrest deflation attributed to the passive degassing of the magma intruded at 4 km during the unrest, while an isotropic source at Nea Kameni simulates a prevailing subsidence occurring since the pre-unrest period (1992–2010).