The Methana peninsula in Greece is the westernmost dormant but geodynamically and hydrothermally active volcanic system of the Hellenic Volcanic Arc, which formed from the subduction of the African tectonic plate beneath the Eurasian plate. Volcanic hazard in Methana is considered “low” as the last historic eruption was registered in approximately 230 BC and no alarming signs were observed in recent times. Nevertheless, several aspects (including the proximity to a densely populated region and the city of Athens) provide sufficient motivation for a dedicated investigation into present-day deformation patterns at the volcano. This study exploits a long stack of 99 C-band Synthetic Aperture Radar (SAR) images acquired by the Copernicus Sentinel-1 satellite constellation along ascending track 102 in the period from March 2015 to August 2019. A Multi-Temporal Interferometric SAR (MT-InSAR) processing approach is exploited using both Persistent (PS) and Distributed (DS) scatterers. Satellite geodetic data from permanent GNSS stations and 2006-2019 GPS benchmark surveying are used as reference to calibrate the MT-InSAR data analysis, as well as to validate MT-InSAR results accuracy. MT-InSAR and geodetic results are combined with geological, seismological and geomorphological data, to better understand the observed potential ground deformation patterns and trends. Line-of-sight displacement velocities within the peninsula reach −18.1 mm/year. The results suggest a complex displacement pattern across the volcano edifice, including local-scale land surface processes, such as settlement in the suburban zones, mass movements and some seasonal fluctuation overlapping with the long-term trend. The retrieved geoinformation provide a first account of deformation patterns, that can feed into the volcano baseline hazard assessment, as well as the monitoring system that is being built in these recent years.
GATSIOS, T.; CIGNA, F.; TAPETE, D.; SAKKAS, V.; PAVLOU, K.; PARCHARIDIS, I. Copernicus Sentinel-1 MT-InSAR, GNSS and seismic monitoring of deformation patterns and trends at the Methana volcano, Greece. Applied Sciences 2020, 10, 6445, doi:10.3390/app10186445