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Abstract Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques have repeatedly proved to be an effective tool for built environments monitoring in areas affected by geological hazards. This paper describes how the Coherent Pixel Technique (CPT) approach has been successfully applied to assess the response of an unstable slope to the different phases of remedial works following a landslide event. The CPT technique was performed on 59 COSMO-SkyMed images obtained between May 2011 and August 2016 and centred on the Quercianella settlement (a small hamlet of Livorno municipality, Tuscany, Italy), where the reactivation of a dormant shallow slide had occurred in March 2011 and, hereafter, a geotechnical intervention, designed with the aim of mitigating the risks, has been conducted from August 2013, lasting thirteen months. The time series of CPT results show a deformation pattern with sudden accelerations (up to 21 mm in few months) corresponding to the beginning of the interventions, during which the area has been excavated to install a drainage well, followed by mild decelerations resulting from the stabilization of the area after the conclusion of the works. In particular, the integration of ground-based subsurface monitoring (inclinometers and piezometers) and DInSAR superficial data has provided consistent results for landslide characterization and helped defining the state of activity and the areal distribution of the sliding surface. Moreover, the performance of remedial works in the landslide-affected area has been observed, showing stabilization in the upper part of the hamlet and the ongoing movement in the lower part. The combined monitoring system also led the geotechnical company in charge of remedial works to design further stabilization works in order to preserve buildings and roads in the moving area. Therefore, the integration of remote sensing techniques and in situ instruments represents a timely and cost-efficient solution for intervention works monitoring, opening new perspectives on designing engineering solutions for the stabilization of unstable slopes. Highlights • DInSAR and conventional monitoring techniques were applied in Livorno, Italy. • Such integration supported the design of remedial works of the landslide. • The performances of the drainage well were observed by DInSAR and inclinometers. • The monitoring system led the company in charge to plan further stabilization works. [ABSTRACT FROM AUTHOR]

An integrated system to analyze slope instabilities over vast areas through the intercomparison of measurements obtained by in-situ and persistent scatterer (PS) interferometry processing of satellite synthetic aperture radar (SAR) data, is here introduced and tentatively named landslide detection integrated system (LaDIS).The persistent scatterer pair (PSP) SAR interferometry technique has been used to process high-resolution SAR images acquired in the 2008–2011 time span by the COSMO-SkyMed satellite constellation, available in a 40 km × 40 km study area in the Palermo Province (Sicily region—Italy). Derived displacement rate estimates from COSMO-SkyMedPS measurements have been analyzed in approximately 10% of the study area for landslide research. Within this area, according to the official landslide inventory map, extremely slow to very slow landslides are dominant, being favored by the presence of heterogeneous clay formations characterized by poor mechanical properties. To prove COSMO-SkyMedPS displacement rates an engineering-geological approach was adopted, tailored to allow a continuous and rapid updating of landslide-inventory maps; to this aim a detailed geological field work has been performed. To guarantee an independent assessment, field surveys have been carried out without sharing information derived from PS data. Almost half (49%) of the active unstable areas identified through COSMO-SkyMedPS measurements were confirmed by the field work. In an additional 26% of cases the greater sensitivity of the satellite has allowed to identify movements, even if very slow, that did not show superficial evidence. A confirmation of the great potentialities of the latest generation of satellite systems also comes from the comparison with the current official landslide-inventory map, updated in 2006. Among the 58% of the total PS measurements that have been used to contour the landslides “in remote”, 84.3% falls outside the polygons of the failures detected in the existing maps, which implies a significant percentage of data to be associated to new landslides or extension of pre-existing landslides. Advantages and drawbacks of exploiting COSMO-SkyMed X-band SAR data to study landslides over wide areas through the proposed approach are finally discussed. [ABSTRACT FROM AUTHOR]