Uplift At Lesina Marina (Southern Italy) Revealed By PSI Techniques

We apply DInSAR PSI techniques to ascending and descending data from ERS and ENVISAT satellites to extract relevant information about mean velocities of stable points located on the Lesina Marina area, a coastal tourist village in Southern Italy, where the excavation of a canal exposed grey micro- and mesocrystalline gyp- sum which is now showing a high density of cavities and sinkholes due to gravitational collapse processes. We ob- serve PS objects undergoing uplift displacements in all the processed data stacks. Derived vertical displacement rates exceed 3-4 mm/y on locations adjacent to the canal, gently decreasing towards the western end of the built up area. High-precision leveling measurements, performed in 1999 and 2010, are compared to the ENVISAT PSI data. Taking into account a constant offset reference velocity value of the PSI data, the differences in velocity measurements exhibit a statistical dispersion around 1-2 mm/y. These observations, supported by ancillary data and in situ investigations performed in the past, seem compatible with processes such as diapirism or the hydration of the residual anhydrite in the core of the gypsum mass. ...