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

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

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

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

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

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

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

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

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

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

DInSAR Analysis and Analytical Modeling of Mount Etna Displacements: The December 2018 Volcano‐Tectonic Crisis

We investigate the 24–27 December 2018 eruption of Mount Etna occurred from fissures located on the volcano eastern flank and accompanied by a seismic swarm, which was triggered by the magma intrusion and continued for weeks after the end of the eruption. Moreover, this swarm involved some of the shallow volcano‐tectonic structures located on the Mount Etna flanks and culminated on 26 December with the strongest event (ML 4.8), occurred along the Fiandaca Fault. In this work, we analyze seismological data and Sentinel‐1 Differential Interferometric Synthetic Aperture Radar (DInSAR) measurements, the latter inverted through analytical modeling. Our results suggest that a dike source intruded, promoting the opening of the eruptive fissures fed by a shallower dike. Moreover, our findings indicate that the activation of faults in different sectors of the volcano may be considered as a response to accommodate the deformations induced by the magma volumes injection.Published5817-58275V. Processi eruttivi e post-eruttiviJCR Journa

Comment on “The 21 August 2017 M d 4.0 Casamicciola Earthquake: First Evidence of Coseismic Normal Surface Faulting at the Ischia Volcanic Island” by

We are writing this comment because many aspects of the analysis presented by Nappi et al. (2018) are debatable. In particular, a major issue is relevant to the conclusion suggested by Nappi et al. (2018) about a seismogenic normal fault with northward dip. This finding is not well‐founded because the authors do not really present a causative source model. In addition, their statement is clearly not consistent with the Differential Interferometric Synthetic Aperture Radar (DInSAR), Global Positioning System (GPS) and seismological measurements presented in the article previously published by De Novellis et al. (2018). Moreover, we also report an evident error in the geologic map proposed by Nappi et al. (2018, their fig. 3).Published313-3156V. Pericolosità vulcanica e contributi alla stima del rischioJCR Journa

The 21 August 2017 Ischia (Italy) Earthquake Source Model Inferred From Seismological, GPS, and DInSAR Measurements

The causative source of the first damaging earthquake instrumentally recorded in the Island of Ischia, occurred on 21 August 2017, has been studied through a multiparametric geophysical approach. In order to investigate the source geometry and kinematics we exploit seismological, Global Positioning System, and Sentinel-1 and COSMO-SkyMed differential interferometric synthetic aperture radar coseismic measurements. Our results indicate that the retrieved solutions from the geodetic data modeling and the seismological data are plausible; in particular, the best fit solution consists of an E-W striking, south dipping normal fault, with its center located at a depth of 800 m. Moreover, the retrieved causative fault is consistent with the rheological stratification of the crust in this zone. This study allows us to improve the knowledge of the volcano-tectonic processes occurring on the Island, which is crucial for a better assessment of the seismic risk in the area.Published2193-22023T. Sorgente sismicaJCR Journa