Study of the ground subsidences in the Sibari Plain (Southern Italy) detected by InSAR data analysis

Abstract

We investigated surface ground deformations in the Sibari Plain (SP - Calabria, Southern Italy) by means of Small Baseline Subset multi-temporal InSAR technique (SBAS), applied to two SAR datasets acquired from 2003 up to 2013 by Envisat (ESA, European Space Agency) and COSMO-SkyMed (ASI, Italian Space Agency) satellites. The retrieved InSAR data show the existence of ground subsidence phenomena up to ~ -20 mm/yr. Our investigation is based on integration between InSAR data and geological, well-logs, land use and hydrogeological information. The results show a direct correlation among subsidence, the thickness of Plio-Pleistocene succession and thickness and lithology of the late Holocene deposits. We identified the fast urbanization of the coastal area during the last ~50 yr and the water table drop as incremental factors of subsidence phenomena. The second factor, due to intensive use of ground water for agriculture, is not the triggering cause of subsidence processes on contrary to the assumption of some previous publications. No evidence of tectonic contribution in the ground deformation pattern is observed.