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We propose a novel set of indexes to classify the information content of Persistent Scatterers (PS) and rate the health of engineering structures at urban to local scale. PS are automatically sampled and grouped via ‘control areas’ coinciding with the building and its surrounding environment. Density over the ‘control areas’ and velocity of PS are converted respectively into: Completeness of Information Index ( I ci ) that reflects the PS coverage grade; and Conservation Criticality Indexes ( I cc ) which rate the health condition of the monument separately for the object and surrounding control areas. The deformation pattern over the structure is classified as isolated (i) or diffused (d) based on the Velocity Distribution Index ( I vd ). Both I ci and I cc are rated from A to E classes using a colour-coded system that intentionally emulates an energy-efficiency scale, to encourage the exploitation of PS by stakeholders and end-users in the practise of engineering surveying. Workability and reliability of the classification indexes are demonstrated over the urban heritage of Florence, Italy, using well established ERS-1/2 (1992–2000) descending, ENVISAT (2003–2010) ascending and descending PS datasets. The indexes are designed in perspective of handling outputs from InSAR processing of higher-resolution time series. [ABSTRACT FROM AUTHOR]

In this paper a methodology is proposed to elaborate landslide activity maps through the use of PS (Persistent Scatterer) data. This is illustrated through the case study of Tramuntana Range in the island of Majorca (Spain), where ALOS (Advanced Land Observing Satellite) images have been processed through a Persistent Scatterer Interferometry (PSI) technique during the period of 2007-2010. The landslide activity map provides, for every monitored landslide, an assessment of the PS visibility according to the relief, land use, and satellite acquisition parameters. Landslide displacement measurements are projected along the steepest slope, in order to compare landslide velocities with different slope orientations. Additionally, a ground motion activity map is also generated, based on active PS clusters not included within any known landslide phenomenon, but even moving, potentially referred to unmapped landslides or triggered by other kinds of geomorphological processes. In the Tramuntana range, 42 landslides were identified as active, four as being potential to produce moderate damage, intersecting the road Ma-10, which represents the most important road of the island and, thus, the main element at risk. In order to attest the reliability of measured displacements to represent landslide dynamics, a confidence degree evaluation is proposed. In this test site, seven landslides exhibit a high confidence degree, medium for 93 of them, and low for 51. A low confidence degree was also attributed to 615 detected active clusters with a potential to cause moderate damage, as their mechanism of the triggering cause is unknown. From this total amount, 18 of them intersect the Ma-10, representing further potentially hazardous areas. The outcomes of this work reveal the usefulness of landslide activity maps for environmental planning activities, being exportable to other radar data and different geomorphological settings. [ABSTRACT FROM AUTHOR]

The temporal and spatial evolution of the pumping-induced ground subsidence in the Gioia Tauro plain (Southern Italy) is investigated exploiting multi-temporal analysis of PSInSAR (Permanent Scatterer Interferometric Synthetic Aperture Radar) data from ERS 1/2 (1992–2001) and ENVISAT (2002–2006) satellites. The PSInSAR derived ground deformation velocity maps and related displacement time series reveal that subsidence rates as high as 10–15 mm/yr are observed in 1992–2006, with the highest velocities (up to 23 mm/yr) occurring between 1992 and 2000 in the central portion of the Plain. Ascending and descending data are combined to extract the vertical and east-west components of ground motions, and reveal the presence of predominant components in the vertical direction due to the compaction of Quaternary sediment in the basin. Aquifer compaction is a consequence of groundwater abstraction. An acceleration index is computed to synthesize the temporal changes between the observed displacements in the two intervals, 1992–2001 and 2002–2006. Deceleration of motions is observed in most of the plain with velocity reductions of about 65% from 1992–2001 to 2002–2006; only a few narrow areas in the southern sector reveal significant increases of motion velocities in the 2002–2006 period, with subsidence velocities exceeding by about 30% those observed in 1992–2001. [ABSTRACT FROM AUTHOR]