A Combination of Space and Terrestrial Geodetic Techniques to Monitor Land Subsidence: Case Study, the Southeastern Po Plain, Italy

Abstract

[1] The southeastern Po Plain is affected by high natural and anthropogenic subsidence. The area is well suited to test the application of an observational strategy which combines different techniques to extract information on the spatial and temporal variability of the subsidence. The simultaneous availability, at a few stations, of several geodetic observation techniques such as Global Positioning System (GPS), gravity, and Interferometric Synthetic Aperture Radar (InSAR) allows for validation of the individual time series. The combination takes advantage of the complementary strengths of each technique by overcoming the limitations inherent in each single technique alone. The combination of velocities derived from the GPS and gravity data, further complemented by the results of the InSAR Permanent Scatterers technique, allows us to monitor continuously, in space and time, vertical crustal movements. This high-density information is of major importance for understanding the processes responsible for the observed deformation. Here long-term trends were derived, enabling us to map the behavior of subsidence (even exceeding 20 mm/yr) with high spatial resolution in the southeastern Po Plain. The uplifting behavior of the Apennines chain bordering the Po Plain is identified together with a narrow zone separating the contrasting vertical crustal movements.

Advanced interpretation of subsidence in Murcia (SE Spain) using A-DInSAR data – modelling and validation

“…An interesting standard DIn-SAR technique application to subsidence analysis was described by Galloway et al (1998), Hoffman (2003) and Galloway and Hoffmann (2007). Advanced A-DInSAR applications are found in Ferretti et al (2004), Zerbini et al (2007) and Bell et al (2008).…”

Satellite positioning and geophysics studies in Italy

“…In many areas of the Po Valley, the natural and tectonic processes were modified by a rapid anthropogenic subsidence induced by underground extraction from aquifer systems and gas fields. The economic impact of man-induced subsidence was extremely high; for this reason this phenomenon has been systematically monitored during the last century (Caputo et al 1970(Caputo et al , 1972Arca and Beretta 1985;Bondesan et al 1997;Zerbini et al 2007), providing the groundwork for a drastic reduction of water withdrawal in that area (Baldi et al 2009, and references therein).…”

First Results from Sentinel-1A InSAR over Australia: Application to the Perth Basin

“…Whilst the method is transferable to other settings, in practice, the results may underestimate the time required to accurately measure multi-year deformation rates, as we have not accounted for seasonal and other non-linear effects. Studies of annually varying signals in GPS time series suggest that 2-3 years of data are required to characterise and remove the seasonal component and avoid biasing the long-term velocity estimate [82,83]. Such non-linear seasonal signals are better characterised with acquisitions at higher temporal resolution, as shown by the time series in Figure 6, and would therefore be best measured at the full repeat of Sentinel-1A and -1B.…”