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Regional deformation in the Central Apennines retrieved by the SBAS IFSAR technique: first results

Simone Atzori(1) and Riccardo Lanari(2)

(1) INGV, Via di Vigna Murata 605, 00143, Italy
(2) IREA-CNR, Via Diocleziano 328, 80124 Napoli, Italy

Abstract

The Central Apennines is a fold and thrust mountain belt presently affected by a NE-SW extensional tectonics. The tectonic strain is released along several normal faults during moderate to large earthquakes. Very little is known on the rates of strain accumulation in this area. In this context an innovative Differential SAR Interferometry (DIFSAR) algorithm has been applied. It is referred to as Small Baseline Subsets (SBAS) technique [1] and allows us to detect and follow the temporal evolution of deformations via an appropriate combination of DIFSAR interferograms. In particular, the SBAS approach relies on the use of small baseline differential SAR interferograms and on the application of the singular value decomposition (SVD) method; the former allows us to mitigate the decorrelation phenomena, the latter to link independent SAR acquisition data sets separated by large baselines. A key point of the applied technique is the implementation of the phase unwrapping step, based on the minimum cost flow algorithm [2], integrated whit a region growing procedure to improve the performances in areas with low SNR. A space-time filtering procedure, based on the observation that the atmospheric phase component is highly correlated in space but not in time, is performed. This operation permits to filter out the atmospheric artifacts and then to improve the accuracy of the detected displacements. Preliminary results on the application of the SBAS technique to the Central Abruzzi area will be presented at the workshop.

References [1] P. Berardino, G. Fornaro, R. Lanari, E. Sansosti: “A new Algorithm for Surface Deformation Monitoring based on Small Baseline Differential SAR Interferograms”, IEEE Transactions on Geoscience and Remote Sensing, Vol. 40, No. 11, pp. 2375-2383, November 2002. [2] M. Costantini and P. A. Rosen: “A Generalized Phase Unwrapping Approach for Sparse Data”, in IEEE Int. Geosci. And Remote Sensing Symp. (IGARSS 1999), Hamburg, Germany, June 1999, pp. 267-269.

 

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry