Geodetic evidence and modeling of a slow, small-scale inflation episode in the Thera (Santorini) volcano caldera, Aegean Sea

Analysis of a radial geodetic monitoring record indicated small-scale inflation of the NW part of the Thera (Santorini) caldera (up to 10 cm baseline length increase) between 1994 and 2000, corresponding to up to 2 * 10−5 strain, and subsequent stabilization especially after 2006, as GPS data indicate. The southern part of the caldera on the contrary remained practically stable. This partial caldera inflation was assigned to slow magma intrusion which was not associated with changes in the seismicity. Using a stochastic approach based on numerical analysis and the theory of graphs and sets, the Mogi source of this magmatic activity was identified between the Nea Kammeni and the Therasia islets, along a major tectonovolcanic lineament, at a depth of around 1 km, or possibly 5.5 km, it remained stable during the whole small-scale inflation period and was associated with small-scale pressure changes. Slow-deformation events have been observed in other volcanoes as well, but they were associated with abrupt seismicity changes.

Research highlights
► Santorini (Thera) volcano inflation.
► Geodetic monitoring.
► Mogi magma source identification.
► Numerical stochastic modeling graph and set theory adjustment.