Fig. 4

Review of the ground deformation pattern, reporting: a Map of the Ischia geodetic monitoring system. b Cumulative Tilt recorded from the continuous titmetric network in 2015–2017 time span (modified from Ricco et al. 2017). Horizontal ground deformation pattern from c horizontal GPS velocity field in the time span 1998–2013 (modified from De Martino et al. 2011) and d mean deformation East-West velocity map from DInSAR measurements 1992–2010 (modified from Castaldo et al. 2017). General subsidence (e) from vertical GPS velocity field in the time span 1998–2013 (modified from De Martino et al. 2011); f from vertical deformation velocity map from DInSAR measurements 1992–2010 (modified from Castaldo et al. 2017); g from vertical GPS time series of EPOM station, located on the top of Monte Epomeo, in the time span 1998–2010 (modified from De Martino et al. 2011); h-i from vertical displacements recorded from the levelling network (in the NW and Monte Epomeo sectors, respectively) in the time span 1987–2010 (modified from Del Gaudio et al. 2011)