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  1. Article ; Online: Dynamic strain anomalies detection at Stromboli before 2019 vulcanian explosions using machine learning

    Pierdomenico Romano / Bellina Di Lieto / Silvia Scarpetta / Ilenia Apicella / Alan T. Linde / Roberto Scarpa

    Frontiers in Earth Science, Vol

    2022  Volume 10

    Abstract: Identifying and characterizing the dynamics of explosive activity is impelling to build tools for hazard assessment at open-conduit volcanoes: machine learning techniques are now a feasible choice. During the summer of 2019, Stromboli experienced two ... ...

    Abstract Identifying and characterizing the dynamics of explosive activity is impelling to build tools for hazard assessment at open-conduit volcanoes: machine learning techniques are now a feasible choice. During the summer of 2019, Stromboli experienced two paroxysmal eruptions that occurred in two different volcanic phases, which gave us the possibility to conceive and test an early-warning algorithm on a real use case: the paroxysm on July, 3 was clearly preceded by smaller and less perceptible changes in the volcano dynamics, while the second paroxysm, on August 28 concluded the eruptive phase. Among the changes observed in the weeks preceding the July paroxysm one of the most significant is represented by the shape variation of the ordinary minor explosions, filtered in the very long period (VLP 2–50 s) band, recorded by the Sacks-Evertson strainmeter installed near the village of Stromboli. Starting from these observations, the usage of two independent methods (an unsupervised machine learning strategy and a cross-correlation algorithm) to classify strain transients falling in the ultra long period (ULP 50–200 s) frequency band, allowed us to validate the robustness of the approach. This classification leads us to establish a link between VLP and ULP shape variation forms and volcanic activity, especially related to the unforeseen 3 July 2019 paroxysm. Previous warning times used to precede paroxysms at Stromboli are of a few minutes only. For paroxysmal events occurring outside any long-lasting eruption, the initial success of our approach, although applied only to the few available examples, could permit us to anticipate this time to several days by detecting medium-term strain anomalies: this could be crucial for risk mitigation by prohibiting access to the summit. Our innovative analysis of dynamic strain may be used to provide an early-warning system also on other open conduit active volcanoes.
    Keywords Stromboli ; strain data ; VLP and ULP signals ; cross-correlation ; SOM ; early warning system ; Science ; Q
    Language English
    Publishing date 2022-08-01T00:00:00Z
    Publisher Frontiers Media S.A.
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: P-wave velocity and density structure beneath Mt. Vesuvius

    Paolo Capuano / Guido Russo / Roberto Scarpa

    Annals of Geophysics, Vol 56, Iss

    a magma body in the upper edifice?

    2013  Volume 4

    Abstract: A high-resolution image of the compressional wave velocity and density structure in the shallow edifice of Mount Vesuvius has been derived from simultaneous inversion of travel times and hypocentral parameters of local earthquakes and from gravity ... ...

    Abstract A high-resolution image of the compressional wave velocity and density structure in the shallow edifice of Mount Vesuvius has been derived from simultaneous inversion of travel times and hypocentral parameters of local earthquakes and from gravity inversion. The robustness of the tomography solution has been improved by adding to the earthquake data a set of land based shots, used for constraining the travel time residuals. The results give a high resolution image of the P-wave velocity structure with details down to 300-500 m. The relocated local seismicity appears to extend down to 5 km depth below the central crater, distributed into two clusters, and separated by an anomalously high Vp region positioned at around 1 km depth. A zone with high Vp/Vs ratio in the upper layers is interpreted as produced by the presence of intense fluid circulation alternatively to the interpretation in terms of a small magma chamber inferred by petrologic studies. In this shallower zone the seismicity has the minimum energy, whilst most of the high-energy quakes (up to Magnitude 3.6) occur in the cluster located at greater depth. The seismicity appears to be located along almost vertical cracks, delimited by a high velocity body located along past intrusive body, corresponding to remnants of Mt. Somma. In this framework a gravity data inversion has been performed to study the shallower part of the volcano. Gravity data have been inverted using a method suitable for the application to scattered data in presence of relevant topography based on a discretization of the investigated medium performed by establishing an approximation of the topography by a triangular mesh. The tomography results, the retrieved density distribution, and the pattern of relocated seismicity exclude the presence of significant shallow magma reservoirs close to the central conduit. These should be located at depth higher than that of the base of the hypocenter volume, as evidenced by previous studies.
    Keywords Volcanic risk ; Tomography and anisotropy ; Gravity anomalies ; Mt.Vesuvius ; Seismic tomography ; Gravity inversion ; Geophysics. Cosmic physics ; QC801-809 ; Physics ; QC1-999 ; Science ; Q
    Subject code 550
    Language English
    Publishing date 2013-11-01T00:00:00Z
    Publisher Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: The 2019 Eruptive Activity at Stromboli Volcano

    Mario Mattia / Bellina Di Lieto / Gaetana Ganci / Valentina Bruno / Pierdomenico Romano / Francesco Ciancitto / Prospero De Martino / Salvatore Gambino / Marco Aloisi / Mariangela Sciotto / Roberto Scarpa / Carmelo Ferlito

    Remote Sensing, Vol 13, Iss 4064, p

    A Multidisciplinary Approach to Reveal Hidden Features of the “Unexpected” 3 July Paroxysm

    2021  Volume 4064

    Abstract: In July and August 2019, Stromboli volcano underwent two dangerous paroxysms previously considered “unexpected” because of the absence of significant changes in usually monitored parameters. We applied a multidisciplinary approach to search for signals ... ...

    Abstract In July and August 2019, Stromboli volcano underwent two dangerous paroxysms previously considered “unexpected” because of the absence of significant changes in usually monitored parameters. We applied a multidisciplinary approach to search for signals able to indicate the possibility of larger explosive activity and to devise a model to explain the observed variations. We analysed geodetic data, satellite thermal data, images from remote cameras and seismic data in a timespan crossing the eruptive period of 2019 to identify precursors of the two paroxysms on a medium-term time span (months) and to perform an in-depth analysis of the signals recorded on a short time scale (hours, minutes) before the paroxysm. We developed a model that explains the observations. We call the model “push and go” where the uppermost feeding system of Stromboli is made up of a lower section occupied by a low viscosity, low density magma that is largely composed of gases and a shallower section occupied by the accumulated melt. We hypothesize that the paroxysms are triggered when an overpressure in the lower section is built up; the explosion will occur at the very moment such overpressure overcomes the confining pressure of the highly viscous magma above it.
    Keywords Stromboli volcano ; ground deformations ; thermal monitoring ; modelling of volcanic sources ; physics of volcanism ; geophysical monitoring ; Science ; Q
    Subject code 550
    Language English
    Publishing date 2021-10-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Faulting mechanism of the Campania–Lucania 1980 earthquake, Italy, from high-resolution, 3D velocity structure, aftershock relocation, fault-plane solutions, and post-seismic deformation modeling

    Roberto Scarpa / Bellina Di Lieto / Luca Crescentini / Antonella Amoruso

    Annals of Geophysics, Vol 54, Iss

    2011  Volume 6

    Abstract: This study performs a detailed reconstruction of the rupture mechanism of the 1980 Campania–Lucania (southern Italy) earthquake. This is achieved by relocation of the main event through computation of fault-plane solutions of the aftershocks, P-wave ... ...

    Abstract This study performs a detailed reconstruction of the rupture mechanism of the 1980 Campania–Lucania (southern Italy) earthquake. This is achieved by relocation of the main event through computation of fault-plane solutions of the aftershocks, P-wave velocity inversion, and analysis of post-seismic ground deformation, which provide an overall picture of the faulting mechanism. All of these data are in favor of a complex rupture mechanism, as already identified by many studies, which consists of three separate events. The present study defines a graben-like rupture, with the first event rupturing a (>20-km-long) segment of a large, high-angle, NE-dipping, SE-NW-striking, normal fault. The two successive ruptures occurred separately, the first along the southern segment, and the second along the northern segment, of a complementary SW-dipping, normal fault. This mechanism is well evidenced by the revised location of the hypocenter of the main event, and the location of the aftershocks and their fault-plane solutions, as well as by the underlying three-dimensional P-wave velocity structure. The model proposed by Amoruso et al. [2005a] that was based on the inversion of co-seismic vertical displacement data is confirmed by the present analyses, as it satisfies all of the available experimental observations, and better constrains the location and fault-plane solutions of the aftershocks, the velocity discontinuities, and the rupture observations at the surface. This conclusion is also supported by analyses of the post-seismic data.
    Keywords Campania-Lucania 1980 earthquake ; Geophysics. Cosmic physics ; QC801-809 ; Physics ; QC1-999 ; Science ; Q ; DOAJ:Geophysics and Geomagnetism ; DOAJ:Earth and Environmental Sciences
    Subject code 550
    Language English
    Publishing date 2011-06-01T00:00:00Z
    Publisher Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Shear-wave velocity structure at Mt. Etna from inversion of Rayleigh-wave dispersion patterns (2 s < T < 20 s)

    Roberto Scarpa / Matthias Ohrnberger / Gilberto Saccorotti / Simona Petrosino / Luigia Cristiano

    Annals of Geophysics, Vol 53, Iss 2, Pp 69-

    2010  Volume 78

    Abstract: ...

    Abstract <mce:style><! /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabella normale"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} --> In the present study, we investigated the dispersion characteristics of medium-to-long period Rayleigh waves (2 s < T < 20 s) using both single-station techniques (multiple-filter analysis, and phase-match filter) and multichannel techniques (horizontal slowness [p] and angular frequency [~] stack, and cross-correlation) to determine the velocity structure for the Mt. Etna volcano. We applied these techniques to a dataset of teleseisms, as regional and local earthquakes recorded by two broad-band seismic arrays installed at Mt. Etna in 2002 and 2005, during two seismic surveys organized by the Istituto Nazionale di Geofisica e Vulcanologia (INGV), sezione di Napoli. The dispersion curves obtained showed phase velocities ranging from 1.5 km/s to 4.0 km/s in the frequency band 0.05 Hz to 0.45 Hz. We inverted the average phase velocity dispersion curves using a non-linear approach, to obtain a set of shear-wave velocity models with maximum resolution depths of 25 km to 30 km. Moreover, the presence of lateral velocity contrasts was checked by dividing the whole array into seven triangular sub-arrays and inverting the dispersion curves relative to each triangle.
    Keywords Mount Etna ; Rayleigh-wave dispersion ; S-wave velocity modeL ; Non-linear inversion ; Triangle method ; Geophysics. Cosmic physics ; QC801-809 ; Physics ; QC1-999 ; Science ; Q ; DOAJ:Geophysics and Geomagnetism ; DOAJ:Earth and Environmental Sciences
    Language English
    Publishing date 2010-05-01T00:00:00Z
    Publisher Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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