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Beccaro, Lisa
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Beccaro, Lisa
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- PublicationOpen AccessMulti-source data analysis to assess the past and present kinematics of the Pisciotta Deep-Seated Gravitational Slope Deformation (southern Italy)(2023-10)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Although Deep-Seated Gravitational Slope Deformations are well-known in the literature, their evolution and kinematics are still poorly understood. Their behavior is often complex and characterized by small movements associated with steady-state creep, alternating with periods of stasis, or accelerating downslope movements that, in some cases, could result in sudden and catastrophic failure events. Therefore, a multidisciplinary approach is often required. In this work, we shed light on the complex geometry and kinematics of the Pisciotta DSGSD, a deep-seated roto-translational sliding involving structurally complex turbiditic rock mass and interacting with man-made infrastructures. To reveal the geometrical features and the spatial and temporal behavior of the analyzed phenomenon, a multidisciplinary investigation was performed. Typical DSGSD landforms were mapped employing in-situ surveys, aided by stereoscopic analysis of historical aerial images and high-resolution drone-based mapping. Structural data and ancillary ground-based surveys revealed the presence of a highly weathered and folded turbiditic sequence, with competent sandstone and calcarenite units alternated by tectonically disrupted, weak argillite and mudrock layers. Remote sensing measurements from optical imagery and Synthetic Aperture Radar satellite data assessed the DSGSD's past and current kinematics, allowing to distinguish a pre-failure period with accelerating displacement rates, a failure period with maximum displacement rates, and a current post-failure period with decelerating displacement rates. Analytical modeling established the deep reach (up to 85 m) of the studied DSGSD as it allowed the estimation of its bottom surface and volume, as verified by available boreholes and inclinometric measurements. Furthermore, numerical modeling outcomes highlighted how the progressive weakening and alteration of the DSGSD material, in conjunction with changes in groundwater dynamics, serve as the primary mechanisms driving the observed kinematics. The models also revealed the intricate interaction between the DSGSD and the neighboring infrastructures.48 10 - PublicationOpen AccessInsights into post-emplacement lava flow dynamics at Mt. Etna volcano from 2016 to 2021 by synthetic aperture radar and multispectral satellite data(2023-09-15)
; ; ; ; ; ; ; ; ; ; ; ; ; Post-emplacement dynamics of lava flows is governed by several factors such as poroelastic deformation of the substrate; gravity-induced repacking and rearrangement of the vesicle-bearing fluid lava and other void spaces by superposed flows; lava densification processes; viscoelastic strain relaxation of the ground caused by the lava load; thermal cooling and contraction of the solid lava; and discrete motion of surface blocks. Here we investigate postemplacement lava flow dynamics at the Mt. Etna volcano, and we infer on the possible causes by exploiting optical and radar satellite data. Synthetic aperture radar data from Sentinel-1 satellite mission provided high-resolution horizontal and vertical displacement rates and displacement time series of the lava flows emplaced on the Mt. Etna volcano summit from January 2016 to July 2021. Sentinel-2 multispectral data allowed to identify the lava flows boundaries emplaced during the December 2018 and May 2019 paroxysms. Finally, high resolution COSMO-SkyMed radar data allowed to account for the topographic changes generated by the lava emplacement by means of stereo radargrammetry technique. Such an unprecedented dataset provided a full picture of the lava flow dynamics, whose kinematics is governed lava cooling, which in turn produce thermal contraction of the lava body and viscous compaction of the underlying substrate. Both phenomena act at different periods, being the thermal contraction predominant for recent lava flows. Downslope sliding is also invoked, especially for recent lava flows emplaced on high slope areas.96 32 - PublicationOpen AccessGround displacement assessment on Pico Volcano, Azores, by multitemporal InSAR dataInterpreting the signal deriving from interferometric synthetic aperture radar (InSAR) analyses in volcanic islands, characterized by strong regional deformations and recurrent seismicity, is a complex and challenging issue. In these zones, the secondary effects connected to the SAR acquisition system cannot be neglected, and it is important to consider that delay phenomena of the electromagnetic waves, due to the propagation in the tropospheric layer and loss of SAR coherence because of dense vegetation, could affect the interferometric phase. This work focuses on Pico, the second largest and the youngest island of the Azores Archipelago (North Atlantic Ocean). This island consists of a central volcano and a fissure zone. These systems are inactive but recurrent microseismicity occurs in a rock volume host- ing a partially crystallized magma storage system, which fed the recent activity of the central volcano. In the same area affected by microseismicity, the main volcanic edifice shows flank instability. All these elements support the hypothesis of possible reactivation of the shallow magmatic system. Aiming to check potential active ground displacements and to define their source, we collected two datasets of C-band Sentinel-1 SAR data, both in descending and ascending acquisition geometry, from January, 2017, to December, 2020. The application of the small baseline subset method of differential InSAR allowed drawing the mean ground velocity maps over the island and the displacement time series, useful to understand the defor- mation evolution. InSAR data only evidence areas affected by small-scale subsidence at the cinder cones of the fissure zone and along the southeastern slope of Pico volcano, where local debris flows activate during rainy periods.
36 28 - PublicationOpen AccessInSAR-Based Detection of Subsidence Affecting Infrastructures and Urban Areas in Emilia-Romagna Region (Italy)The study of deformation signals associated with seismicity in alluvial plain areas is a challenging topic that, however, is increasingly studied thanks to the great aid given by remote sensing techniques that exploit Synthetic Aperture Radar (SAR) data. This study focuses on the determination of the deformation field within the Emilia-Romagna Region (northern Italy), in the area comprising Modena, Reggio Emilia, and Parma cities. SAR data acquired along both orbits during the Sentinel-1 and Cosmo-SkyMed satellite missions were processed with the Small Baseline Subset interferometric technique from June 2012, after the serious seismic swarm of May 2012, to January 2022, just before the two earthquakes occurred in February 2022. The results, validated with Global Navigation Satellite System measurements, do not highlight displacements correlated with the seismicity but, thanks to their high spatial resolution, it was possible to discriminate areas affected by noticeable subsidence phenomena: (i) the highly industrialized areas located north of the municipalities of Reggio Emilia and Modena cities and (ii) a sector of the high-speed railway sited north of the Reggio Emilia city centre, close to the Reggio Emilia AV Mediopadana station. Here we show that, at least since 2012, the latter area is affected by subsidence which can be related to the secondary consolidation process of the fine soils loaded by the railway embankment. The piezometric level analysis also suggests that the lowering of the groundwater table could accelerate the subsidence rate, affecting the stability of infrastructures in highly populated and industrialized areas
43 19 - PublicationOpen AccessAseismic Creep, Coseismic Slip, and Postseismic Relaxation on Faults in Volcanic Areas: The Case of Ischia Island(2023-03-27)
; ; ; ; ; ; ;We performed a joined multitemporal and multiscale analysis of ground vertical movements around the main seismogenic source of Ischia island (Southern Italy) that, during historical and recent time, generated the most catastrophic earthquakes on the island, in its northern sector (Casamicciola fault). In particular, we considered InSAR (2015–2019) and ground-levelling data (1987–2010), attempting to better define the source that caused the recent 2017 earthquake and interpret its occurrence in the framework of a long-term behavior of the fault responsible for the major historical earthquakes in Casamicciola. Our results unambiguously constrain the location and the kinematics of the 2017 rupture and further confirm the presence of a relatively large sliding area west of the 2017 surface break. Overall, the studied seismogenic fault reveals a complex dynamic, moving differentially and aseismically in the pre- and post-seismic event, in response to the long-term subsidence of the central sector of the island, dominated by Mt. Epomeo. The fault segment that slipped coseismically also is evidence of post-seismic viscous relaxation. The long-term differential vertical movement on the apparently creeping eastern sector of the Casamicciola fault provides an estimate of the slip rate occurring on the fault (0.82 mm/y−1). The analysis of the time of occurrence and the magnitude of the known historical earthquakes reveals that this rate is consistent with the recurrence of the earthquakes that occurred during at least the past three centuries and suggests that the time to the next seismic event at Casamicciola might be a few decades. More generally, our findings provide evidence of the link between subsidence and earthquakes in volcanic areas indicating, in this case, a high hazard for the island of Ischia. Results might be also useful for characterizing capable faulting in similar volcano-tectonic settings worldwide.255 60 - PublicationOpen AccessCoupling Flank Collapse and Magma Dynamics on Stratovolcanoes: The Mt. Etna Example from InSAR and GNSS Observations(2023-02-02)
; ; ; ; ; ; ; ; ; ; ; ; ; Volcano ground deformation is a tricky puzzle in which different phenomena contribute to the surface displacements with different spatial–temporal patterns. We documented some high variable deformation patterns in response to the different volcanic and seismic activities occurring at Mt. Etna through the January 2015–March 2021 period by exploiting an extensive dataset of GNSS and InSAR observations. The most spectacular pattern is the superfast seaward motion of the eastern flank. We also observed that rare flank motion reversal indicates that the short‐term contraction of the volcano occasionally overcomes the gravity‐controlled sliding of the eastern flank. Conversely, fast dike intrusion led to the acceleration of the sliding flank, which could potentially evolve into sudden collapses, fault creep, and seismic release, increasing the hazard. A better comprehension of these interactions can be of relevance for addressing short‐term scenarios, yielding a tentative forecasting of the quantity of magma accumulating within the plumbing system.85 25 - PublicationOpen AccessMultitemporal and Multisensor InSAR Analysis for Ground Displacement Field Assessment at Ischia Volcanic Island (Italy)(2021)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Volcanic islands are often affected by ground displacement such as slope instability, due to their peculiar morphology. This is the case of Ischia Island (Naples, Italy) dominated by the Mt. Epomeo (787 m a.s.l.), a volcano-tectonic horst located in the central portion of the island. This study aims to follow a long temporal evolution of ground deformations on the island through the interferometric analysis of satellite SAR data. Different datasets, acquired during Envisat, COSMOSkyMed and Sentinel-1 satellite missions, are for the first time processed in order to obtain the island ground deformations during a time interval spanning 17 years, from November 2002 to December 2019. In detail, the multitemporal differential interferometry technique, named small baseline subset, is applied to produce the ground displacement maps and the associated displacement time series. The results, validated through the analysis and the comparison with a set of GPS measurements, show that the northwestern side of Mt. Epomeo is the sector of the island characterized by the highest subsidence movements (maximum vertical displacement of 218 mm) with velocities ranging from 10 to 20 mm/yr. Finally, the displacement time series allow us to correlate the measured ground deformations with the seismic swarm started with the Mw 3.9 earthquake that occurred on 21 August 2017. Such correlations highlight an acceleration of the ground, following the mainshock, characterized by a subsidence displacement rate of 0.12 mm/day that returned to pre-earthquake levels (0.03 mm/day) after 6 months from the event.496 73