CAPS: A New Method for the Identification of Different Surface Displacements in Landslide and Subsidence Environments through Correlation Analysis on Persistent Scatterers Time-Series from PSI

Abstract

Persistent Scatterer Interferometry (PSI) is one of the most powerful tools for identifying and monitoring areas exposed to surface deformations such as landslides or subsidence. In this work, we propose a new method that we named CAPS (Correlation Analysis on Persistent Scatterers), to extend the capability of PSI in recognizing and characterising areas influenced by complex ground deformations and differential motions. CAPS must be applied to both ascending and descending orbits separately and comprises three major steps: (i) calculating the cross-correlation matrix on detrended PS time-series; (ii) extracting PS pairs with similarity greater than a given threshold; (iii) grouping PS in families by sorting and classification. Thus, in both orbits, PS Families identify groups of PS with similar movements. This allows distinguishing sectors characterised by different displacements over time even in areas with similar LOS (Line of Sight) velocities. As test sites, we considered four different known geological scenarios: two representing landslide environments (Santo Stefano d’Aveto and Arzeno, both in Liguria, NW Italy) and two subsidence environments (Rome and Venice, urban and surrounding areas). This method proved to be versatile, applicable to different geological situations and at different scales of observation, for recognizing both regional and local differential deformations.

Coexistence of a Marginal Mountain Community with Large-Scale and Low Kinematic Landslide: The Intensive Monitoring Approach

“…The geological setting is one of the landslidepredisposing factors for the large deformation affecting upper Graveglia Valley. Among the several large-scale landslides in the upper Graveglia Valley [48,52,53], this research addresses the deep-seated gravitational slope deformation (DsGSD) that involves the entire slope from the Mt. Chiappozzo ridge to the valley floor, affecting the hamlets of Reppia, Prato di Reppia (PDR) and Arzeno (ARZ), and including Piani di Oneto (PDO), interpreted as complex DSGSD trench and subordinately karst depression (Figure 2c).…”

“…Concerning the local community, the velocity and the damage detected show that adapting to living on such phenomena could be feasible and affordable with ordinary maintenance of buildings and infrastructure. Moreover, the data acquired in the monitoring campaign and further analyses with the InSAR dataset [52] suggests a revision of the current landslide zonation map for improved land-planning support. In addition, the SAR data could help to focus mitigation actions on the most critical area [69], improving the community's resilience and reducing its abandonment.…”