Advanced interpretation of interferometric SAR data to detect, monitor and model ground subsidence: outcomes from the ESA-GMES Terrafirma project

Abstract

Land subsidence is a common natural hazard striking extensive areas worldwide, with severe impacts on economy and environment. Subsidence has been recognized as one of geohazards needing research efforts and knowledge transfer at international level, especially when urban fabrics and infrastructures are directly involved in the land settling. Policies and solutions for land subsidence management can be different. Despite this variability, where mitigation methods need to be adopted, mapping, monitoring and simulation of subsidence have to precede their design and implementation. In this framework, Earth Observation (EO) and remote sensing have a major role to play. Satellite Synthetic Aperture Radar Interferometry, thanks to its wide spatial coverage and its millimeter accuracy, provides a valuable contribution in the management of hazard posed by subsidence-related deformation. The ESA-GMES Terrafirma project (2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014) has worked for the promotion of the persistent scatterer interferometry, a family of techniques ideally suited for the assessment of magnitude of surface deformations associated with subsidence phenomena. Within the Terrafirma Project a series of products, based on the integration of EO technologies and in situ data, has been established and delivered to a wide community of end user. Three case studies, outcomes of the Terrafirma project, are presented: the wide area of Rome (Italy), the Anthemountas basin and the Kalochori village (Greece). These case studies have been selected with the purpose of showing the essential contribution of interferometric data during the main activities that must be covered when dealing with geohazard investigations (i.e., mapping, monitoring and modeling). These three case studies are meant to be representative of the suite of services delivered by the Terrafirma project to specific end users with the legal mandated to manage the geohazard.

The Parallel SBAS Approach for Sentinel-1 Interferometric Wide Swath Deformation Time-Series Generation: Algorithm Description and Products Quality Assessment

“…11 relevant to the Fiumicino Airport and surroundings (Southwest of the urban area of Rome, in central Italy). In this case, the map reveals a spatially extended subsidence pattern related to the interaction between natural and man-induced causes, i.e., compaction of unconsolidated sediments and progressive urbanization [82]. The observed deformation pattern is characterized by a deformation rate up to 2 cm/year, clearly shown by the temporal evolution of the displacement reported for the pixel labeled as P2 and identified with a black star in Fig.…”

Imaging Multi-Age Construction Settlement Behaviour by Advanced SAR Interferometry

“…The study area, located in the municipalities of Rome and Fiumicino (Italy), is affected by important subsidence phenomena [23], features a high geological and geotechnical variability, and has been built upon for approximately 100 years. Moreover, in the region, a large urban expansion is in progress and additional expansion is already planned.…”

Understanding the Implementation Challenges of Urban Resilience Policies: Investigating the Influence of Urban Geological Risk in Thessaloniki, Greece

“…In cases where elevation rapidly decreases and considering the fact that those buildings are predominantly one-to two-storey residential dwellings, it can be easily concluded that they are largely exposed to impact from heavy rain and flooding events. This is a typical phenomenon in many southern European cities [39].…”

“…Lastly, it is worth recalling that the intensification of industrial development and agricultural activities and the consequent increasing water demand have recently led to overexploitation of local aquifers and amplification of compaction of compressible deposits and ground subsidence phenomena, further increasing the geological vulnerability of Perea [34,39]. In a scenario of increasing groundwater overexploitation of the aquifer system in the coastal zone of Thermaikos Municipality, land subsidence may become a further threat, principally in those areas where Quaternary alluvial formations are thick, with a lowering of the ground level.…”