Clues to the cause of the 2011-2013 Campi Flegrei caldera unrest, Italy, from continuous GPS data

From 2006 to spring 2013, Campi Flegrei (CF) caldera, Italy, was mostly uplifting at an increasing rate, particularly high from 2011. We show that the 2011-2013 accelerated uplift and 1980-2010 inflation and deflation phases can be explained by a two-source conceptual model similar to that proposed by Amoruso et al. (2014) (reference model). However, pressurization of the sole thin quasi-horizontal similar to 4000 m deep source, responsible for large-scale 1980-2010 deformation, can explain the whole 2011-2013 deformation, while activity of the shallower Solfatara hydrothermal source, responsible for residual 1980-2010 deformation, appears constant. These results suggest a predominantly magmatic unrest in 2011-2013. Near-real-time comparison of observations and reference model predictions can provide additional information for short-term eruption forecasting at CF; a similar approach could be followed also in other volcanic environments.