GNGTS 2016 - Atti del 35° Convegno Nazionale

114 GNGTS 2016 S essione 1.1 to 3000 m below sea level (ViDEPI, 2009). Pyroclastic and lava deposits drilled around and below 2000 m depths in deep wells (ViDEPI, 2009) testify to early volcanism dating back to the Early Pleistocene (Di Girolamo et al. , 1976). More recent, intense explosive volcanism occurred since 400 ky ago (Rolandi et al. , 2003), and climaxed with the emplacement of the Ignimbrite Campana pyroclastic flow deposits at 40 ky (De Vivo et al. , 2001). Abundant primary and reworked pyroclastic inputs largely contributed to filling of the Campania Plain since the Middle Pleistocene, probably accompanied by slowing of subsidence (Brancaccio et al. , 1991), which however continued in the last 100 ky (Romano et al. , 1994; Santangelo et al. , 2010). More recent (< 40 ky) vertical displacements at the northern boundary of the Campania Plain are testified by geomorphological information and subsurface stratigraphy data (Romano et al. , 1994; Cinque et al. , 2000). Materials and methods. The tectonic geomorphology study has been carried out by the analysis of detail-scale topography data (Regione Campania 1:5000 scale maps; LiDAR images) and field surveys. The latter were carried out along the eastern margin of the northern Campania Plain, were several Quaternary shallow marine, alluvial and pyroclastic units have been identified. The Quaternary stratigraphy study of the Plain margin has been integrated with subsurface data obtained by several published and unpublished borehole logs. Satellite interferometry data are based on phase comparison of SAR images acquired at different times and perspective views. Permanent Scatterers Interferometric Synthetic Aperture Radar (PS-InSAR; Ferretti et al. , 2001; Vilardo et al. , 2009) is one of the latest applications of SAR time series data analysis. Permanent Scatterers are radar image points on the ground that show stable interferometric phase behaviour for wide look-angle variations over time, and are used to estimate the progressive sub-vertical motion of the ground surface. In this study, we have used satellite interferometry data spanning over an about 20 year long time span, i.e. PS datasets by ERS 1 + 2 (1992 - 2000) and ENVISAT (2002 - 2010), obtained by Ministero dell’Ambiente, della Tutela del Territorio e del Mare (MATTM). PS-InSAR datasets have been analysed through geostatistical spatial analysis in order to construct deformation maps for the time windows covered by the two datasets. The use of a clustering geostatistical methodology has allowed identifying clusters of kinematically homogeneous PS with reference to mean PS velocity values. The spatial analysis identifies statistically significant elements using the Anselin Local Moran’s I statistic. The calculated indexes show whether the apparent similarity (spatial clustering of high/low values) or dissimilarity (spatial outliers) is more pronounced than one would expect in a random distribution. Following Perrone et al. (2013), clues to the interpretation of single kinematic domains identified through the statistical analysis, and boundaries between kinematic clusters, have been provided by geological/geomorphological information. Results. The field surveys and the geomorphological analysis provide new data on the early stages of development of the northern Campania Plain and late Quaternary faulting. The Fig. 1 – Simplified geological map of the northern part of the southern Apennines Tyrrhenian margin, showing the coastal grabens and the main Quaternary faults at their boundaries. The white frame indicates location of the study area.