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  • 1
    Electronic Resource
    Electronic Resource
    Long-term observation of volcanic tremor on Stromboli volcano (Italy): A synopsis (1996)
    Springer
    Pure and applied geophysics 147 (1996), S. 57-82 
    Details
    ISSN: 1420-9136
    Keywords: Volcanic tremor ; cluster analysis ; Stromboli volcanoes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The features of seismic activity on Stromboli are discussed and compared in terms of their relationship with the main changes of volcanic activity from 1990 to 1993. We considered a statistical approach for our data analysis. Cluster analysis was used to seek out classes of spectra which might characterize the condition of the volcanic system. The classes we have found provide insights into a scenario which evolves through different phases of volcanic activity, from paroxysms to low activity. We show that episodes of lava effusion and lava fountaining are heralded by variations in the spectral features of tremor after a preparation time. This result highlights the importance of tremor, and reveals that long-term observations are key to examine slow modifications in a volcanic system such as Stromboli, characterized by open conduits, and persistent explosive activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00876436
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    Paper (German National Licenses)
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  • 2
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    Fracture Reactivation and Magma Intrusion: The Case of the 1989 Fissure System at Mt Etna, Italy (2010)
    Details
    Publication Date: 2017-04-04
    Description: Fracture Reactivation and Magma Intrusion: The Case of the 1989 Fissure System at Mt Etna, Italy FALSAPERLA Susanna1, Fabrizio CARA2, Antonio ROVELLI2, Marco NERI1, Boris BEHNCKE1, Valerio ACOCELLA3 1 Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania, Piazza Roma 2, 95123, Catania, Italy 2 Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Roma1, Via di Vigna Murata 605, 00143 Roma, Italy 3 Dipartimento Scienze Geologiche Roma Tre. L. S.L. Murialdo 1, 00146 Roma, Italy We focus on the role of a dry (without lava emission) fracture system, consisting of extension fractures and normal faults, which opened at Mt Etna, Italy, during the 1989 flank eruption. The NNW-SSE fracture system is located on the mid-upper SE flank of the volcano, and has experienced significant seismic activity during the past two decades. By using excellent documented records of seismic and volcanic activity on 24 November 2006 (the latter encompassing Strombolian activity, lava fountaining, ash fallout, pyroclastic flows, and lava emission from multiple vents at the Southeast Crater), we analyze the interaction between seismic radiation and the afore-mentioned fracture system. Our results highlight the importance of this system in controlling the polarization properties of seismic waves 17 years after its formation. In addition, the SE end of the 1989 fracture zone extends into several active faults, suggesting that they represent a single long structure, which plays an important role in the volcano-tectonic dynamics of Etna. Finally, this study shows how fracture reactivation can also occur by means of magma intrusion, strongly controlling the transfer of magma within a volcanic edifice.
    Description: Published
    Description: Besse, Clermont-Ferrand, France
    Description: open
    Keywords: Magma Intrusion ; Volcanic tremor ; Mt. Etna ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Oral presentation
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  • 3
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    Fixing Criteria for Volcanic Unrest Warning (2022)
    MISCELLANEA INGV
    Details
    Publication Date: 2022-10-28
    Description: In volcanic observatories worldwide, geophysical and geochemical data are usually collected remotely, providing continuous information about the state of volcanoes even in unfavorable conditions with respect to visibility and access to the area of eruptive centers. Early stages of unrest can be detected with high reliability; nonetheless, style and, in particular, intensity of eruptions are diffcult to predict. Consequently, it turns out important to identify critical moments after which the development of a paroxysmal activity becomes highly probable. In this perspective, we exploit a machine learning (ML) method for the analysis of seismic data continuously acquired by the permanent seismic network at Etna, Italy. Threshold criteria, which are based on parameters derived from the ML system and the number of stations where changes are detected, have been established with the scope of automatic alert flagging. As mild unrests may continue for weeks and even months, there is the need to adjust the trigger criteria with respect to style and intensity of the impending phenomenon. Our choice of the criteria was guided by so-called “Receive Operation Characteristics” (ROC) curves. These are based on the trade-off between the rate of False Positives and True Positives. With a more sensitive setting one can flag more paroxysms (True Positives); however, this may have the cost to flag an alert, but no paroxysm occurs. Carrying out various tests considering both the signal characteristics and the number of stations where the thresholds were met, we identified robust configurations allowing us to issue an alert of an impending paroxysm, widely avoiding the risk of false warnings. The system we propose here can provide timely and indicative information on possible eruptive scenarios to Civil Protection and other stakeholders. Also, It can be a guide for fixing onset and end-times of paroxysmal phenomena, which are especially helpful when image-based monitoring is hindered, for instance, by meteorological conditions. Finally, if others the possibility to effectively re-analyze long time spans of data recorded in the past.
    Description: This work was designed within the project IMPACT (A multidisciplinary Insight on the kinematics and dynamics of Magmatic Processes at Mt. Etna Aimed at identifying preCursor phenomena and developing early warning sysTems). IMPACT belongs to the Progetti Dipartimentali INGV [DIP7], https://progetti.ingv.it/index.php/it/progetti-dipartimentali/vulcani/impact#informazioni-sul-progetto.
    Description: Published
    Description: Catania (Italy)
    Description: 8T. Sismologia in tempo reale e Early Warning Sismico e da Tsunami
    Keywords: Volcanic tremor ; volcano unrest ; Etna ; volcanic hazard ; eruptive activity ; forecasting ; pattern classification ; 04.08. Volcanology ; 04.06. Seismology ; 05.06. Methods ; 05.08. Risk ; 05.04. Instrumentation and techniques of general interest
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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  • 4
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    A machine learning method for seismic signal monitoring: A contribution to the detection of the potential volcanic hazard on Etna, Italy (2022)
    egusphere-egu22-1151, 2022
    Details
    Publication Date: 2022-10-27
    Description: The dynamics driving an eruption play a crucial role in the impact volcanic activity has on the community at large. The interpretation of geophysical and geochemical changes heralding a volcanic unrest is a fundamental key to forecasting upcoming phenomena. However, the style and intensity of the eruption are difficult to predict, even in open-conduit volcanoes where eruptions can be relatively frequent. This is the case of Etna, in Italy, one of the most active basaltic volcanoes in the world. In 2021, fifty-two lava fountains arose from its Southeast Crater accompanied by lava emissions and ash fallout, which disrupted air and road traffic in numerous Sicilian municipalities. Lava fountains are just one of the typical eruptive styles of Etna. Strombolian activity and lava flows are also relatively frequent here, each with its own characteristics in terms of intensity and social impact. We developed a machine learning (ML) method for the analysis of the seismic data continuously acquired by the local stations of the Etna permanent seismic network, exploiting the spectral characteristics of the signal. Its design started from: i) the need to detect the volcanic hazard, and ii) provide timely and indicative information on possible eruptive scenarios to the Civil Protection and the Authorities. Besides the identification of anomalies in the data, which flag enhanced volcano dynamics in its early stages, we investigate on clues concerning the potential intensity level of eruptive phenomena. The method works in near real time and can effectively contribute to the multidisciplinary analysis of volcanic hazard.
    Description: This work was undertaken within the project IMPACT (A multidisciplinary Insight on the kinematics and dynamics of Magmatic Processes at Mt. Etna Aimed at identifying preCursor phenomena and developing early warning sysTems). IMPACT belongs to the Progetti Dipartimentali INGV [DIP7], https://progetti.ingv.it/index.php/it/progetti-dipartimentali/vulcani/impact#informazioni-sul-progetto.
    Description: Published
    Description: Vienna (Austria)
    Description: 8T. Sismologia in tempo reale e Early Warning Sismico e da Tsunami
    Keywords: Volcanic tremor ; volcano unrest ; Etna ; eruptive activity ; thresholds ; forecasting ; 04.08. Volcanology ; 04.06. Seismology ; 05.06. Methods ; 05.04. Instrumentation and techniques of general interest
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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  • 5
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    Energy threshold changes in volcanic activity at Mt. Etna (Italy) inferred from volcanic tremor (2022)
    Springer Nature
    Details
    Publication Date: 2022-10-28
    Description: From the 2010s on, pattern classification has proven an effective method for flagging alerts of volcano unrest before eruptive activity at Mt. Etna, Italy. The analysis has been applied online to volcanic tremor data, and has supported the surveillance activity of the volcano that provides timely information to Civil Protection and other authorities. However, after declaring an alert, no one knows how long the volcano unrest will last and if a climactic eruptive activity will actually begin. These are critical aspects when considering the effects of a prolonged state of alert. An example of longstanding unrest is related to the Christmas Eve eruption in 2018, which was heralded by several months of almost continuous Strombolian activity. Here, we discuss the usage of thresholds to detect conditions leading to paroxysmal activity, and the challenges associated with defining such thresholds, leveraging a dataset of 52 episodes of lava fountains occurring in 2021. We were able to identify conservative settings regarding the thresholds, allowing for an early warning of impending paroxysm in almost all cases (circa 85% for the first 4 months in 2021, and over 90% for the whole year). The chosen thresholds also proved useful to predict that a paroxysmal activity was about to end. Such information provides reliable numbers for volcanologists for their assessments, based on visual information, which may not be available in bad weather or cloudy conditions.
    Description: Project IMPACT (A multidisciplinary Insight on the kinematics and dynamics of Magmatic Processes at Mt. Etna Aimed at identifying preCursor phenomena and developing early warning sysTems). IMPACT belongs to the Progetti Dipartimentali INGV [DIP7], https://progetti.ingv.it/index.php/it/progetti-dipartimentali/vulcani/impact#informazioni-sul-progetto.
    Description: Published
    Description: 17895
    Description: 4V. Processi pre-eruttivi
    Description: JCR Journal
    Keywords: Volcanic tremor ; Volcano monitoring ; Pattern recognition ; Self Organizing maps ; Fuzzy clustering ; Mt. Etna ; 04.06. Seismology ; 04.08. Volcanology ; 05.01. Computational geophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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