Casagli, Nicola

Cecchi, Roberto

Del Ventisette, Chiara

Fanti, Riccardo

Petrangeli, P.

Tapete, Deodato

English

DEL VENTISETTE, Chiara

Florence Research

Geophysical Research AbstractsVol. 13, EGU2011-8387, 2011EGU General Assembly 2011© Author(s) 2011Satellite and ground-based radar interferometry for detection andmonitoring of structural instability in archaeological sitesDeodato Tapete (1), Nicola Casagli (1), Riccardo Fanti (1), Chiara Del Ventisette (1), Roberto Cecchi (2), and PiaPetrangeli (2)(1) Department of Earth Sciences, University of Firenze, Firenze, Italy (deodato.tapete@unifi.it), (2) Italian Ministry ofCultural Heritage and Activities, Rome, ItalySustainable and cost-effective management strategies of huge archaeological areas with high concentration of mon-uments require accurate identification of the most critical sectors and structures, on which appropriate restorationinterventions should be focused. Integrated approaches combining on-site investigations and conventional monitor-ing systems can also benefit from the employment of advanced remote sensing technologies specifically suitablefor the detection of structural and ground motions affecting archaeological heritage. In the last years SyntheticAperture Radar Interferometry (InSAR) techniques have been increasingly used to measure terrain motions dueto both natural and human-induced processes with different kinematics, demonstrating their capabilities for non-invasive diagnosis and conservation of cultural heritage. Here we discuss the results from the highly detailed sur-veys performed at different scales on archaeological sites within the urban area of Rome (Italy), in the frameworkof co-operation with the Commissioner for the archaeological areas of Rome and Ancient Ostia, Italian Ministryof Cultural Heritage and Activities. The above mentioned surveys, based on both satellite and ground-based radarmonitoring campaigns, successfully contributed to the analysis of spatial and temporal evolution of past and recentstructural and ground motions on Palatino Hill and Roman Forum. For these areas a long history of instabilityevents is recorded; the severest collapse occurred in November 2005 and damaged the Farnesian Walls in the NEsector of the hill. Such events are not so rare in archaeological contexts where the geological substratum is proneto instability (e.g., block toppling, landsliding, cavities collapse) and affected by groundwater seepage and surfacewater infiltration; weathering and decay processes can also compromise the structures, formerly subterranean andcurrently completely exposed, disaggregating the ancient mortars and weakening the masonry. Combining specificcapabilities of satellite and ground-based InSAR technologies, a new integrated methodology was implemented,performing a monitoring campaign, respectively, at ‘archaeological site scale’ and ‘single monument scale’. Per-sistent Scatterer Interferometry (PSI) was exploited to both reconstruct past deformation occurred in 1992-2000(ERS1/2 data) and measure the ongoing deformation (2003-2009; RADARSAT-1 data) with millimetre accuracyand monthly data acquisition frequency. Complementarily, a real-time structural monitoring by means of Ground-Based InSAR (GB-InSAR) instrumentation was focused on the monuments most affected by past instability events,continuously controlling their stability with high sampling frequency (up to 1 image every 6 minutes) since April2009. Time-series analysis of long temporal radar satellite data stacks and interpretation of the spatial distributionof the average annual displacement velocities highlighted localized ground motions (up to 20 mm/yr, as measuredin the area of the Temple of Magna Mater along the SW slope of Palatino Hill), suggesting a strong correlationwith the subterranean cavity network and local geological setting, and also contributing to the identification of themost critical sectors where programmed restorations are being currently carried out. On the other hand, GB-InSARanalysis confirmed an overall stability of the monuments during the monitoring period, allowing real-time warn-ing in case of occurrence of differential movements recognizable within the constantly updated displacement timeseries. As demonstrated by the present case study, the suitability for performing multiple scale analyses makes theInSAR techniques efficient diagnostic tools to distinguish unstable sectors from the stable ones and, consequently,to provide recommendations and guidelines for planning adequate countermeasures and prevention of instabilityevents potentially hazardous for the conservation of archaeological heritage.

Satellite and ground-based radar interferometry for detection and monitoring of structural instability in archaeological sites

https://flore.unifi.it/bitstream/2158/405766/1/Tapete%20et%20al%20GRA%20vol%2013%20EGU%202011.pdf

Satellite and ground-based radar interferometry for detection and monitoring of structural instability in archaeological sites

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