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Early detection and in-depth analysis of deformation phenomena by radar interferometry
No full textAbstract
The spaceborne differential interferometric SAR (DInSAR) technique may play an important role in the measurement of land deformation phenomena, especially in urban, suburban and industrial areas. In order to fully exploit its capabilities and increase its operational use, this paper proposes two complementary levels of analysis. The first one is a comprehensive low-cost screening, in order to detect unknown subsidence phenomena over large areas. This analysis, which provides a first estimation of deformations, has to be performed using a limited set of SAR images. The second level includes an in-depth quantitative analysis based on large image stacks, which requires more image acquisition and data processing resources. This type of analysis can be typically used to study deformation phenomena of special relevance, where an effective support to the decision-makers requires a fully quantitative estimation of deformations. The two levels of analysis were proved over a test area of about 2100 km2, located in Catalonia (Spain). Without any a priori information, seven deformation phenomena were detected using a reduced set of interferograms. Furthermore, the quantitative analysis of a subsidence of small spatial extent, which was based on ascending and descending datasets, confirmed the capability of DInSAR to quantitatively assess deformation phenomena.
Keywords
Subsidence;
Deformation;
Monitoring;
Remote sensing;
SA
Pasquasia potassic salts mine (Central Sicily, Italy): ground deformation phenomena pointed out by means of Differential SAR Interferometry (DInSAR)
No full text
Resolving vertical and east-west horizontal motion from differential interferometric synthetic aperture radar : The L'Aquila earthquake
Full text linkAnalysis of surface coseismic displacement has already been obtained for the 6 April 2009 L'Aquila (central Italy) earthquake from differential interferometric synthetic aperture radar (DInSAR) data. Working jointly on ascending and descending DInSAR data makes for a step forward with respect to published preliminary estimates: we process data in order to retrieve a continuous displacement pattern, both in the vertical and horizontal directions, the latter being limited to the eastward component because of the low sensibility of the SAR images used to resolve northward motion. Our analysis provides new insights on the horizontal component of displacement, obtaining a clear picture of eastward displacement patterns over the epicentral area. This result is noteworthy, as until now little information has been available on horizontal displacement following normal-fault events in the central Apennines (Umbria-Marche, 1997, and L'Aquila, 2009), given the lack of dense GPS networks, the only available source of horizontal displacement data in this area. Inverted fault characteristics from such data also show noteworthy differences compared to previous studies, localizing the Paganica fault as the causative fault for the earthquake
Persistent Scatterer Interferometry: Potential, Limits and Initial C- and X-band Comparison
No full textThis paper is focused on the potential and limits of Persistent Scatterer Interferometry (PSI), a powerful remote sensing technique used to measure deformation phenomena. It only refers to satellite-based PSI techniques, focusing on the most important sources of C-band SAR data: ERS and Envisat. In addition, it compares C- and X-band results, considering data from the high-resolution TerraSAR-X sensor. The paper begins with a description of the main characteristics of PSI. It then discusses the most important PSI products and their performances, analyzing their spatial sampling, the so-called residual topographic error and PSI geocoding, the average displacement rates, and the deformation time series. As C-band products are concerned, the paper reports some relevant PSI validation results, which come from the ESA-funded Terrafirma Validation Project. Regarding the X-band, it describes the results obtained over the City of Barcelona by processing 13 TerraSAR-X images. The last part discusses the main limits of PSI
Interferometria SAR Differenziale per il Rilevamento delle Deformazioni
No full textThe differential interferometric SAR technique represents a powerful remote sensing tool for the monitoring of terrain deformations. The paper concisely describes the properties of the differential interferometric phase, which represents the main observation for the estimation of the deformations. Then the paper discusses the main features of a new interferometric SAR procedure which applies an integrated approach for the treatment of DInSAR observations. In particular, the interferometric SAR processing and the least squares adjustment procedure to estimate the terrain deformations velocity are described. Finally an application of the proposed procedure is illustrated over simulated data
Two radar interferometric approaches to monitor slow and fast land deformations
No full textDifferential interferometric synthetic aperture radar (DInSAR)is a deformation measurement technique that couples two
interesting characteristics. First, being based on remotely sensed data it offers operational advantages, like low cost data acquisition, wide
area coverage, and temporally regular acquisitions. Second, it can be based on rigorous modeling and estimation procedures, which allows
some of the most advanced techniques to derive measurements with high quality standards, comparable with those of some geodetic
methods. The scope of this paper is to describe two complementary approaches to measure slow from a few millimeters up to some
centimeters per year and fast land deformation up to few meters per year . Emphasis is given to the description of the former approach,
which requires multiple SAR images of the same phenomenon and an advanced analysis procedure. The effectiveness of both approaches
is illustrated through two applications on mining areas of small spatial extent located in Spain. In one case the DInSAR capability to fully
detect shape and magnitude of an unknown fast deformation phenomenon is highlighted, whereas in the second one a detailed deformation
map is derived over an urban area, where deformations up to 30 mm/ year occur
Applicazioni in ambito urbano di interferometria differenziale
No full textThis paper describes two examples of deformation monitoring based on two complementary differential interferometric SAR (Synthetic Aperture Radar) techniques. The first application concerns a thin and elongated infrastructure, the main dike of the Port of Barcelona, while the second one regards a group of buildings in an urban area. In the first application, the dike was measured by using a Persistent Scatterers technique called Stable Point Network and implemented by Altamira Information. This application illustrates the high quality of the deformation estimated derived by this technique. The second application, which was measured by using a classical DInSAR approach and a small set of interferograms, shows the effectiveness of a simple analysis in an operational context
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