Monitoring of Land Subsidence in Ravenna Municipality Using Integrated Sar - GPS Techniques: Description and First Results

Abstract

Commission VII, WG VII/2 KEY WORDS: Ravenna, Land Subsidence, GPS, DInSAR, Staring Spotlight, Sentinel-1 ABSTRACT:The Emilia Romagna Region (N-E Italy) and in particular the Adriatic Sea coastline of Ravenna, is affected by a noticeable subsidence that started in the 1950s, when the exploitation of on and off-shore methane reservoirs began, along with the pumping of groundwater for industrial uses. In such area the current subsidence rate, even if lower than in the past, reaches the -2 cm/y. Over the years, local Authorities have monitored this phenomenon with different techniques: spirit levelling, GPS surveys and, more recently, Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques, confirming the critical situation of land subsidence risk. In this work, we present the comparison between the results obtained with DInSAR and GPS techniques applied to the study of the land subsidence in the Ravenna territory. With regard to the DInSAR, the Small Baseline Subset (SBAS) and the Coherent Pixel Technique (CPT) techniques have been used. Different SAR datasets have been exploited: ERS-1/2, ENVISAT, TerraSAR-X and Sentinel-1. Some GPS campaigns have been also carried out in a subsidence prone area. 3D vertices have been selected very close to existing persistent scatterers in order to link the GPS measurement results to the SAR ones. GPS data were processed into the International reference system and the comparisons between the coordinates, for the first 6 months of the monitoring, provided results with the same trend of the DInSAR data, even if inside the precision of the method.

The integration of a new sensor and geomatic techniques for monitoring the Roman bridge S. Angelo on the Savuto river (Scigliano, Italy)

“…In addition to providing detailed 3D models, TLS can be used to determine physical characteristics of considerable relevance for structural analyzes, both static and dynamic [6]. Remote sensing is also used in an increasingly widespread manner and techniques based on terrestrial and airborne Synthetic-aperture Radar (SAR) allow for useful information at the level of a single building or of the area of land in which it is located [7].…”

Different processes affecting long-term Ravenna coastal drainage basins (Italy): implications for water management

“…The area has suffered from an intensive subsidence rate, up to a maximum value of 110 mm/year in the 1970s, during the high economic boom due to deep groundwater natural gas withdrawals (Teatini et al 2005). More recently, the rates of subsidence have significantly decreased in many areas due to strong mitigation law imposed on groundwater exploitation (Carminati and Martinelli 2002), but they still remain important in some places like the coastal area (Artese et al 2016;Bitelli et al 2015;Cerenzia et al 2016;Teatini et al 2005). The subsiding land raised the need to pump more water out of the coastal basins to keep pace with the rising groundwater level (Antonellini et al 2019).…”

InSAR Monitoring of Italian Coastline Revealing Natural and Anthropogenic Ground Deformation Phenomena and Future Perspectives

“…Such phenomena, i.e., ground deformation and uplift, arises from both shallow (e.g., compaction of sediments and groundwater pumping) and deeper processes (e.g., gas/oil exploitation, volcanic and tectonic processes [1,[4][5][6][7]). On one side, the compaction of high-porosity near-surface sediments caused by groundwater overexploitation often dominates ground deformation, with rates up to tens of cm/year [8][9][10][11][12]. On the other side, more in-depth activities contribute to coastal deformation with rates up to a few mm/year [2,11].…”