Abstract
In this study, we present the detection and characterization of ground displacements in the urban area of Pisa (Central Italy) using Interferometric Synthetic Aperture Radar (InSAR) products. Thirty RADARSAT-2 and twenty-nine COSMO-SkyMed images have been analyzed with the Small BAseline Subset (SBAS) algorithm, in order to quantify the ground subsidence and its temporal evolution in the three-year time interval from 2011 to 2014. A borehole database was reclassified in stratigraphical and geotechnical homogeneous units, providing the geological background needed for the local scale analysis of the recorded displacements. Moreover, the interferometric outputs were compared with the last 30 years’ urban evolution of selected parts of the city. Two deformation patterns were recorded by the InSAR data: very slow vertical movements within the defined stability threshold (±2.5 mm/yr) and areas with subsidence rates down to −5 to −7 mm/yr, associated with high peak velocities (−15 to −20 mm/yr) registered by single buildings or small groups of buildings. Some of these structures are used to demonstrate that the high subsidence rates are related to the recent urbanization, which is the trigger for the accelerated consolidation process of highly compressible layers. Finally, this urban area was a valuable test site for demonstrating the different results of the C- and X-band data processing, in terms of the density of points and the quality of the time series of deformation.
Highlights
Subsidence is a broad term usually referring to the ground lowering induced by natural or anthropic factors
The analysis of the two A-DInSAR datasets shows that the urban area of Pisa is not characterized by the presence of regional scale deformation patterns, such as large subsidence bowls related to water overexploitation (Figure 3)
This type of large scale deformation has been observed in other sectors of the Tuscany region, such as the urban area of Pistoia, where a water overexploitation-related subsidence was recorded [61], or the geothermal area of Larderello, where a large subsidence bowl, produced by geothermal activity, has been detected [62]
Summary
Subsidence is a broad term usually referring to the ground lowering induced by natural or anthropic factors. The various analysis algorithms that have been developed in the last two decades allow reaching the millimeter accuracy, in addition to a regional-scale coverage of data at a reasonable cost [10]. These advantages have been exploited to monitor the ground subsidence of urban areas in many nations around the world, including. C-band RADARSAT-2 (RSAT) and X-band COSMO-SkyMed (CSK) data have been processed with the Small BAseline Subset (SBAS) approach, to provide the deformation maps of the urban area of Pisa (Central Italy) in the time interval 2011–2014. New deformation-affected areas and trend changes in the time series of deformation of selected buildings have been examined, to demonstrate the existing relation between recorded displacements, local geological setting, and urban development
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
