119 research outputs found

    DInSAR deformation time series for monitoring urban areas: The impact of the second generation SAR systems

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    We investigate the capability improvement of the DInSAR techniques to map deformation phenomena affecting urban areas, by performing a comparative analysis of the deformation time series retrieved by applying the full resolution Small BAseline Subset (SBAS) DInSAR technique to selected sequences of SAR data acquired by the ENVISAT, RADARSAT-1 and COSMO-SkyMed (CSK) SAR data. The presented study, focused on the city of Napoli (Italy), allows us to quantify the dramatic increase of the DInSAR coherent pixel density achieved by exploiting the high resolution X-Band CSK SAR images with respect to the RADARSAT-1 and ENVISAT products, respectively; this permits us to analyze nearly all the structures located within the investigated urbanized area and, in many cases, also portions of a same building. © 2012 IEEE

    Brief Communication: Rapid mapping of landslide events: the 3 December 2013 Montescaglioso landslide, Italy

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    We present an approach to measure 3-D surface deformations caused by large, rapid-moving landslides using the amplitude information of high-resolution, X-band synthetic aperture radar (SAR) images. We exploit SAR data captured by the COSMO-SkyMed satellites to measure the deformation produced by the 3 December 2013 Montescaglioso landslide, southern Italy. The deformation produced by the deep-seated landslide exceeded 10 m and caused the disruption of a main road, a few homes and commercial buildings. The results open up the possibility of obtaining 3-D surface deformation maps shortly after the occurrence of large, rapid-moving landslides using high-resolution SAR data

    GIS integration of DInSAR measurements, geological investigation and historical surveys for the structural monitoring of buildings and infrastructures. An application to the Valco San Paolo urban area of Rome

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    Structural health monitoring is a crucial issue in areas with different hazard sources, such as Italy. Among non-invasive monitoring techniques, remote sensing provides useful information in supporting the management process and safety evaluations, reducing the impact of disturbances on the functionality of construction systems. The ground displacement time-series based on the analysis of Differential Interferometric Synthetic Aperture Radar (DInSAR) measurements, as well as the information about the geology of the area and the geometry of the construction under monitoring, provides useful data for the built environment's structural assessment. This paper focuses on the structural monitoring and damage assessment of constructions based on the GIS integration of DInSAR measurements, geological investigation, historical surveys and 3D modeling. The methodology is applied to the residential area of Valco San Paolo in the city of Rome (Italy). Once the geological interpretation has confirmed the results of the DInSAR measurements, a quick damage assessment that considers all the possible conditions of the pre-existing damage at the time zero of the monitoring is shown for a damaged manufact in the area. The presented results highlight how the strategy to correlate the DInSAR-monitored ground settlements with the damage scales allows potentially to monitor continuous construction systems

    Geodetic model of the 2016 Central Italy earthquake sequence inferred from InSAR and GPS data

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    We investigate a large geodetic data set of interferometric synthetic aperture radar (InSAR)and GPS measurements to determine the source parameters for the three main shocks of the 2016Central Italy earthquake sequence on 24 August and 26 and 30 October (Mw6.1, 5.9, and 6.5,respectively). Our preferred model is consistent with the activation of four main coseismic asperitiesbelonging to the SW dipping normal fault system associated with the Mount Gorzano-Mount Vettore-Mount Bove alignment. Additional slip, equivalent to aMw~ 6.1–6.2 earthquake, on a secondary (1) NEdipping antithetic fault and/or (2) on a WNW dipping low-angle fault in the hanging wall of the mainsystem is required to better reproduce the complex deformation pattern associated with the greatestseismic event (theMw6.5 earthquake). The recognition of ancillary faults involved in the sequencesuggests a complex interaction in the activated crustal volume between the main normal faults and thesecondary structures and a partitioning of strain releas

    A QUANTITATIVE ASSESSMENT OF DInSAR TIME SERIES ACCURACY IN VOLCANIC AREAS: FROM THE FIRST TO SECOND GENERATION SAR SENSORS

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    We perform a quantitative assessment of the accuracy of Differential SAR Interferometry (DInSAR) time series in volcanic areas, retrieved through “first” and “second generation” SAR data. In particular, we analyze the impact that the wavelengths and looking geometries may have in the DInSAR measurement retrieval depending on the radar system. To this aim, we focus on the DInSAR algorithm referred to as Small BAseline Subset (SBAS) to generate mean deformation velocity maps and corresponding time series starting from sequences of SAR images. Moreover, we consider collections of SAR data acquired by the ERS-1/2 and ENVISAT (C-band), and COSMO-SkyMed (Xband) sensors over the volcanic area of the Campi Flegrei caldera, Southern Italy. We invert these SAR data sequences through the SBAS-DInSAR technique, thus obtaining C- and X- band deformation time series that we compare to continuous GPS measurements, the latter assumed as reference. The achieved results provide, in addition to a clear picture of the surface deformation phenomena already occurred and occurring in the selected case study, relevant indications for the analysis of the SBAS-DInSAR time series accuracies in volcanic areas passing from the first to second generation SAR sensors.PublishedMünich1IT. Reti di monitoraggio e Osservazionirestricte

    Soil deformation analysis through fluid-dynamic modelling and DInSAR measurements: a focus on groundwater withdrawal in the Ravenna area (Italy)

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    This study aims at assessing the deformation processes affecting an area NW of the city of Ravenna (northern Italy), caused by groundwater withdrawal activities. In situ data, geologic and structural maps, piezometric measurements, underground water withdrawal volumes, and satellite C-band SAR data were used to jointly exploit two different techniques: 1) fluid-dynamic and geomechanical modelling (by RSE S.p.A), and 2) Differential Synthetic Aperture Radar Interferometry (DInSAR) analysis (by CNR - IREA). The results of the comparative analysis presented in this work brought new evidence about the contribution of groundwater withdrawal to the total subsidence affecting the area during the 2000-2017 time interval. In particular, they show an increase of the subsidence from year 2000 to 2010 and a decrease from year 2010 to 2017. These results are generally in line with groundwater withdrawal data that report a reduction of the extracted water volumes during the considered temporal interval. Meantime, they show a delay effect in the subsidence process, partially recovered during the 2010-2017 thanks to a stabilisation of the extracted groundwater volumes. The presented results shade new light on the groundwater withdrawal contribution to the subsidence of the analysed zone, although further investigations are foreseen to better clarify the ongoing scenario

    Dunning rat prostate adenocarcinomas and alternative splicing reporters: powerful tools to study epithelial plasticity in prostate tumors in vivo

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    Using alternative splicing reporters we have previously observed mesenchymal epithelial transitions in Dunning AT3 rat prostate tumors. We demonstrate here that the Dunning DT and AT3 cells, which express epithelial and mesenchymal markers, respectively, represent an excellent model to study epithelial transitions since these cells recapitulate gene expression profiles observed during human prostate cancer progression. In this manuscript we also present the development of two new tools to study the epithelial transitions by imaging alternative splicing decisions: a bichromatic fluorescence reporter to evaluate epithelial transitions in culture and in vivo, and a luciferase reporter to visualize the distribution of mesenchymal epithelial transitions in vivo

    Splicing Reporter Mice Revealed the Evolutionally Conserved Switching Mechanism of Tissue-Specific Alternative Exon Selection

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    Since alternative splicing of pre-mRNAs is essential for generating tissue-specific diversity in proteome, elucidating its regulatory mechanism is indispensable to understand developmental process or tissue-specific functions. We have been focusing on tissue-specific regulation of mutually exclusive selection of alternative exons because this implies the typical molecular mechanism of alternative splicing regulation and also can be good examples to elicit general rule of “splice code”. So far, mutually exclusive splicing regulation has been explained by the outcome from the balance of multiple regulators that enhance or repress either of alternative exons discretely. However, this “balance” model is open to questions of how to ensure the selection of only one appropriate exon out of several candidates and how to switch them. To answer these questions, we generated an original bichromatic fluorescent splicing reporter system for mammals using fibroblast growth factor-receptor 2 (FGFR2) gene as model. By using this splicing reporter, we demonstrated that FGFR2 gene is regulated by the “switch-like” mechanism, in which key regulators modify the ordered splice-site recognition of two mutually exclusive exons, eventually ensure single exon selection and their distinct switching. Also this finding elucidated the evolutionally conserved “splice code,” in which combination of tissue-specific and broadly expressed RNA binding proteins regulate alternative splicing of specific gene in a tissue-specific manner. These findings provide the significant cue to understand how a number of spliced genes are regulated in various tissue-specific manners by a limited number of regulators, eventually to understand developmental process or tissue-specific functions
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