Separating natural and anthropogenic vertical movements in fast subsiding areas: The Po Plain (N. Italy) Case

The geological and the anthropogenic components of vertical movement act on different time scales (millions to thousands years and hundreds to tens of years respectively). This peculiarity has been used in order to separate the factors controlling sea-level changes in the Po plain area. The component due to long term geological processes is calculated from stratigraphic data (commercial wells and seismic lines). Adding to this long term component the contribution of Pleistocene deglaciation obtained from analytical models, an estimate of the total natural component of vertical velocities is obtained. The validity of these values is confirmed by comparison with velocities obtained from archaeological data and detailed palynological and paleontological analyses. The anthropogenic components can be inferred by comparison between the total natural vertical velocities we calculate and vertical velocities obtained from other data sets. Two applications are proposed using tide gauge records and geodetic data respectively.