Casagli, Nicola

Cigna, Francesca

Del Ventisette, Chiara

Liguori, V.

English

Florence Research

Geophysical Research AbstractsVol. 12, EGU2010-14368, 2010EGU General Assembly 2010© Author(s) 2010Landslide detection and long-term monitoring in urban area by means ofadvanced interferometric techniquesFrancesca Cigna (1), Chiara Del Ventisette (1), Vincenzo Liguori (2), and Nicola Casagli (1)(1) Department of Earth Sciences, University of Firenze, Via La Pira 4, 50121 Firenze, Italy. (francesca.cigna@unifi.it), (2)Department of Structural, Aerospace and Geotechnical Engineering, University of Palermo, Viale delle Scienze, 90128Palermo, Italy.This work aims at illustrating the potential of advanced interferometric techniques for detection and long-termmonitoring of landslide ground deformations at local scale.Space-born InSAR (Synthetic Aperture Radar Interferometry) has been successfully exploited in recent years tomeasure ground deformations associated to processes with slow kinematics, such as landslides, tectonic motions,subsidence or volcanic activity, thanks to both the standard single-interferogram approach (centimeter accuracy)and advanced time-series analyses of long temporal radar satellite data stacks (millimeter accuracy), such asPersistent Scatterers Interferometry (PSI) techniques.In order to get a complete overview and an in-depth knowledge of an investigated landslide, InSAR satellitemeasures can support conventional in situ data. This methodology allows studying the spatial pattern and thetemporal evolution of ground deformations, improving the spatial coverage and overcoming issues related toinstallation of ground-based instrumentation and data acquisition in unstable areas.Here we describe the application of the above-mentioned methodology on the test area of Agrigento, Sicily (Italy),affected by hydrogeological risk. The town is located in Southern Sicily, at edge of the Apennine-Maghrebianthrust belt, on the Plio-Pleistocene and Miocene sediments of the Gela Nappe. Ground instabilities affect theurban area and involve the infrastructures of its NW side, such as the Cathedral, the Seminary and many privatebuildings. An integration between InSAR analyses and conventional field investigations (e.g. structural damagesand fractures surveys) was therefore carried out, to support Regional Civil Protection authorities for emergencymanagement and risk mitigation.The results of InSAR analysis highlighted a general stability of the whole urban area between 1992 and 2007.However, very high deformation rates (up to 10-12 mm/y) were identified in 1992-2000 in the W slope of thetown, within the crown and the main scarp area of the Addolorata landslide (occurred in July 1966), and thuswas highlighted that the phenomenon was still active. The time-series analysis performed in the NW area of thetown, also allowed measuring acceleration (up to 13 mm/y) of the deformation rates near the main Cathedral,starting from August 2006 and persisting until the end of the monitoring period (2007). The new informationabout the state of activity of these landslides were discussed with the Civil Protection authorities to plan furtherfield investigations and structural surveys to be carried out in the areas at higher risk.The analysis on Agrigento confirmed the capabilities of this integrated approach for detection of ground defor-mations, long-term monitoring of landslides and, finally, management and mitigation of hydrogeological risk inurban area at local scale.

Landslide detection and long-term monitoring in urban area by means of advanced interferometric techniques

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Landslide detection and long-term monitoring in urban area by means of advanced interferometric techniques

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