Natural versus anthropogenic
subsidence of Venice
L. Tosi
Institute of Marine Sciences, CNR, Venezia, Italy
P. Teatini
Dept. of Civil, Environmental and Architectural Engineering,
University of Padova, Padova, Italy
T. Strozzi
Gamma Remote Sensing, Gumligen, Switzerland
We detected land displacements of Venice by Persistent Scatterer Interferometry using ERS and ENVISAT
C-band and TerraSAR-X and COSMO-SkyMed X-band acquisitions over the periods 1992-2010 and 2008-2011,
respectively. By reason of the larger observation period, the C-band sensors was used to quantify the
long-term movements, i.e. the subsidence component primarily ascribed to natural processes. The high
resolution X-band satellites reveal a high effectiveness to monitor short-time movements as those induced
by human activities. Interpolation of the two datasets and removal of the C-band from the X-band map
allows discriminating between the natural and anthropogenic components of the subsidence. A certain
variability characterizes the natural subsidence (0.9 ± 0.7 mm/yr), mainly because of the heterogeneous
nature and age of the lagoon subsoil. The 2008 displacements show that man interventions are responsible
for movements ranging from -10 to 2 mm/yr. These displacements are generally local and distributed
along the margins of the city islands.
