Analysis of surface displacements in urban areas

Issue

A public building requiring modernization works is located in an area where some landslides were mapped in the past. In order to support the decisionmakers and the designers of the project and to assess the sitespecific risk of the area, the past evolution of the instability processes of the slopes need to be evaluated.

Solution

A-DInSAR (Advanced satellite SAR Interferometry) analyses have been performed by using images acquired in the last years by the COSMO-SkyMed constellation of satellites and available in the Italian Space Agency (ASI) archive. Thanks to A-DInSAR, in fact, it is possible was to estimate the ground and structures displacement rates and trends occurred in the past, within the area of interest. Two different datasets of satellite images (with different orbital geometries) have been analyzed aiming to investigate displacement patterns both in vertical and horizontal directions.

Achievements

More than 10,000 measurement points have been achieved and analysed. No widespread displacements have been detected in the entire study area. Nevertheless, some localized measurement points sowing displacements in the investigated period (velocity rates ranging between 5 and 10 mm/yr) and moving away from the sensor have been identified on a geotechnical infrastructure. The results, in combination with field surveys, allowed to define the risk condition of the area, useful for a preliminary design stage.