Paolo Farina

Space‐borne and ground‐based SAR interferometry as tools for landslide hazard management in civil protection

In recent years, SAR interferometry has become one of the most popular emerging techniques for the assessment of ground displacements, and, as such, it is of great interest as a possible operational tool for civil protection institutions having to deal with landslide risk. The paper presents some of the results obtained in northern Italy during a research project aimed at testing the potentiality of the application of C‐band space‐borne interferometry and Ku‐band ground based interferometry during different specific civil protection activities. Main research objectives were the detection of the movements of complex earth and rock slides affecting built‐up areas during the 1990s, and the near real‐time monitoring of a reactivated rotational earth slide over an emergency period of 15 days. Results of space‐borne interferometry did qualitatively fit with the geological interpretation of the mass movements and with ground truths such as damaged buildings and in situ monitoring systems. However, this was not achieved in quantitative terms, suggesting that this technique should be used limitedly for displacement recognition and not monitoring. On the other hand, ground‐based interferometry proved valuable both for a qualitative and a quantitative estimate of slope movements. Nonetheless, the research has also enabled the limitations that are still to be tackled in order to bring these systems to an operational usage in civil protection to be highlighted.

SAR interferometry from satellite and ground-based system for monitoring deformations on the Stromboli volcano

After the collapse of a landslide of 20 million m/sup 3/ from the NE slope of the Stromboli volcano and the subsequent tsunami at the end of December 2002, a ground-based InSAR system (interferometric synthetic aperture radar) was installed on the flank of the Sciara del Fuoco, a collapse depression formed 5 million BP. Through the radar measurement it has been possible to assess the deformation field over a large portion of the target area and to differentiate different processes. Twelve months of radar monitoring have permitted to follow the temporal and spatial evolution of the mass movement in the Sciara. The landslide showed wide fluctuations in the displacement rate, between 0.6 and 10 mm/h, with acceleration phases coinciding with episodes of more intense effusive activity. The dynamic of the volcano has been also studied through the use of DInSAR from satellite platform. Different images acquired from the ERS2 satellite before and after the collapse of the landslide have been interferometrically processed in order to extract information about the ground deformation occurred on the island due to the volcanic activity.

Ground-based SAR interferometry as a tool for landslide monitoring during emergencies

This work concerns the application of ground-based synthetic aperture radar (GB-SAR) interferometry as a tool for the landslide monitoring during emergencies. An example of application of this technique to the Cortenova landslide, Italian Alps, is described. The deformation maps provided by GB-SAR interferometry allows for the study of the landslide temporal evolution and the volume estimation of the material involved in the mass movement. This information is important for the assessment of future risk scenarios needed to draw up the emergency plans for civil protection purposes.

A ground-based interferometer for the safety monitoring of landslides and structural deformations

This paper concerns the use of Ground-Based Synthetic Aperture Radar (GB-SAR) interferometer for the measurement of terrain movements and structural deformations in man-made structures. This instrument can measure displacements with a precision up to a fraction of millimetre. The spatial extension of the monitored area can be of a few squared kilometres. With respect to other traditional geotechnical instruments, the presented GB-SAR interferometer can remotely monitor the target scene, providing deformation maps and not only point-like measurements.

On the Use of Ground-Based SAR Interferometry for Slope Failure Early Warning: the Cortenova Rock Slide (Italy)

This contribution illustrates the capabilities of groundbased SAR interferometry (GBInSAR) to be used as an early warning for the detection of precursory ground displacements that can suggest the imminent occurrence of a slope failure. SAR data were acquired by a ground-based SAR system, belonging to the LISA interferometer series designed by the Joint Research Centre of the European Commission, over the Cortenova rock slide (Regione Lombardia, Italy) and interferometrically analyzed in near-real time. The system was used to provide, during the 2002–2003 emergency caused by the landslide reactivation, the civil protection authorities with an operational tool for the assessment of the mass movement temporal evolution. After the main rupture occurred at the beginning of December 2002, which caused severe damage to the Bindo Village, destroying several houses and factories, interrupting one key connection road and partially damming a river, concern over the occurrence of further collapses of the still unstable slope led to the evacuation of 900 people living close to the run-out area. Such a situation induced the civil protection authorities to arrange a real-time monitoring system. Measurements of ground displacements continuously collected by the radar system up to May 2003, besides detecting the portions of the slope affected by movement, revealed the gradual deceleration of the residual movements passing from 5 cm d−1 to 0.3 cm d−1.

Land subsidence in the Firenze-Prato-Pistoia basin measured by means of spaceborne SAR interferometry

This work concerns the application of space-borne SAR interferometry (InSAR) to the study of the land subsidence problem affecting the urban areas of the Firenze-Prato-Pistoia basin (Central Italy). Such a phenomenon is mainly related to the large amount of ground-water pumped for the industrial activities of this area. The interferometric analysis has been carried out by means of both traditional Differential Interferometry (DInSAR) and Permanent Scatterers technique (PS) by using SAR data acquired by the ESA ERS1/2 satellites. Different patterns of terrain subsidence have been detected in the industrial areas of the monitored basin.

Landslide monitoring on a short and long time scale by using ground-based SAR interferometry

Ground-based Synthetic Aperture Radar (GB-SAR) interferometry is used to monitor the Tessina landslide. This is a complex mass movement in the Italian Eastern Alps. Radar data, acquired during a 10-day campaign, are interferometrically processed. Image couples taken at the same position but at different times are used to estimate terrain slope deformations on a short temporal scale of a few hours. In addition, SAR images acquired with a baseline are processed to extract information on the current topography of the landslide area. Comparison with the terrain morphology of the scene at earlier times allows to evaluate the landslide activity on a long time scale spanning a few years.

Monitoring the Tessina landslide by a ground-based SAR interferometer and assessment of the system accuracy

This work concerns the application of groundbased SAR interferometry (GB-InSAR) for the monitoring of the Tessina landslide, using the LISA (Linear SAR) system developed at the JRC. This landslide is continuously monitored by a topographic system. For this reason it has been chosen as a test site to fully confirm the accuracy of the, GB-InSAR. The GB-InSAR-derived ground displacements have been compared with those obtained by a set of topographic benchmarks placed in the unstable areas.

The 10-Mile Slide and Response of a Retaining Wall to Its Continuous Deformation

Open image in new window The 10-mile Slide has a volume of about 750,000 m3 and is sliding on a through-going shear surface at velocities up to 10 mm/day. Its importance is associated with the location of a highway and a railway line within its boundaries. Risks posed to the railway were managed through monitoring and running patrols in front of trains, and a pile retaining wall was installed immediately downslope from the tracks to prevent deformations caused by loosening of materials associated with the slope deformations and delay the retrogression of the landslide. Displacement measurements of the piles have monitored the response of the wall as the landslide retrogressed upslope from the railway track. This paper presents a brief description of the 10-mile Slide geologic context, its kinematics, mechanism, and evolution followed by a presentation of measured response of the retaining wall as the landside retrogressed.

Integration of InSAR and GIS in the Study of Surface Faults Caused by Subsidence-Creep-Fault Processes in Celaya, Guanajuato, Mexico

In Celaya city, Subsidence‐Creep‐Fault Processes (SCFP) began to become visible at the beginning of the 1980s with the sprouting of the crackings that gave rise to the surface faults “Oriente” and “Poniente”. At the present time, the city is being affected by five surface faults that display a preferential NNW‐SSE direction, parallel to the regional faulting system “Taxco‐San Miguel de Allende”. In order to study the SCFP in the city, the first step was to obtain a map of surface faults, by integrating in a GIS field survey and an urban city plan. The following step was to create a map of the current phreatic level decline in city with the information of deep wells and using the “kriging” method in order to obtain a continuous surface. Finally the interferograms maps resulted of an InSAR analysis of 9 SAR images covering the time interval between July 12 of 2003 and May 27 of 2006 were integrated to a GIS. All the maps generated, show how the surface faults divide the city from North to South, in two zone...