Mapping inflation at Santorini volcano, Greece, using GPS and InSAR

Abstract

Recent studies have indicated that for the first time since 1950, intense geophysical activity is occurring at the Santorini volcano. Here, we present and discuss the surface deformation associated with this activity, spanning from January 2011 to February 2012. Analysis of satellite interferometry data was performed using two well‐established techniques, namely, Persistent Scatterer Interferometry (PSI) and Small Baseline Subset (SBAS), producing dense line‐of‐sight (LOS) ground deformation maps. The displacement field was compared with GPS observations from 10 continuous sites installed on Santorini. Results show a clear and large inflation signal, up to 150 mm/yr in the LOS direction, with a radial pattern outward from the center of the caldera. We model the deformation inferred from GPS and InSAR using a Mogi source located north of the Nea Kameni island, at a depth between 3.3 km and 6.3 km and with a volume change rate in the range of 12 million m3 to 24 million m3 per year. The latest InSAR and GPS data suggest that the intense geophysical activity has started to diminish since the end of February 2012.

Volcanic Hazard Assessment at Santorini Volcano: A Review and a Synthesis in the Light of the 2011-2012 Santorini Unrest

“…The increased seismicity was accompanied by up to 10 cm inflation of the islands measured by GPS networks and by radar interferometry, corresponding to a modelled volume increase of about 10-20 million m 3 at 3-6 km beneath the northern caldera basin (Newman et al, 2012;Parks et al, 2012;Papoutsis et al, 2013;Foumelis et al, 2013). Small increases in the fluxes of H2 and mantle-derived CO2 also occurred during the unrest (Parks et al, 2013;Tassi et al, 2013).…”

Santorini unrest 2011–2012: an immediate Bayesian belief network analysis of eruption scenario probabilities for urgent decision support under uncertainty

“…In January 2011, there was a sharp increase in seismic activity beneath the Kameni islands in the Santorini caldera (Thera), and surface deformation was detected that was interpreted as the inflation of a magmatic source (Newman et al 2012;Papoutsis et al 2013). While the most common presumption was that the unrest was due to magmatic intrusion at shallow depth, it is also plausible that it was a result of wider tectonic stresses, and not simply or necessarily solely volcanic in origin.…”

Dionysos Satellite Observatory and Higher Geodesy Laboratory: History and Perspectives

“…SAR can be used to serve a wide range of scientific aims, related to remote sensing, such as climate change, environment, resources, natural hazards, etc. The main focus for the laboratories, is the integration of GNSS and SAR to accurately detect three dimensional tectonic deformation, as SAR offers high accuracy results for elevation (Papoutsis et al, 2013).…”