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  • 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology  (15)
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  • 1
    Publication Date: 2020-11-30
    Description: Mt. Vesuvius (southern Italy) is one of the volcanoes that poses the greatest risk in the world because of its highly explosive eruptive style and its proximity to densely populated areas. The urbanization around Mt. Vesuvius began in ancient times, and the impact of eruptions on human activities has been severe. This is testified to by the ruins of Pompeii, which are covered by the products of the plinian eruption that took place in A.D. 79 (Sigurdsson et al. 1985), and more recently by the published reports of the eruptions that occurred from 1631 to 1944. For these reasons, Mt. Vesuvius was also one of the first volcanoes to be equipped with monitoring instruments. Pioneering instrumental observations began just before the second half of the 1800s, when the Vesuvius Observatory was founded in 1841 (Imbò 1949). At that time, Vesuvius was very active (Ricciardi 2009), and its effusive and explosive eruptions often caused damage to the surrounding areas. At the same time, it was a famous tourist attraction that drew travelers from all over the world (Gasparini and Musella 1991). Since the middle of the 1800s, at least 12 eruptions have occurred that have been superimposed on persistent intra-crater activity that has been characterized by Strombolian explosions and by the formation of small lava lakes. The last eruption occurred on 18 March 1944 and marked a change in the status of Mt. Vesuvius, as it entered a closed-conduit phase that persists today. Following this last eruption, a change occurred in the 1960s, as documented by an increase in the occurrence rate of earthquakes. Since 1972, the monitoring of Mt. Vesuvius has improved over time and become more systematic, so that there is a remarkable dataset relating to the current phase of quiescence. Over more than a century and a half of observations, many monitoring instruments have been used for Mt. Vesuvius, including early seismometers, several of which are now kept in the Museum of Volcanology of the Vesuvius Observatory. The present monitoring system is based on seismological, geodetical geodetical, and geochemical observations performed using an instrumental network that was designed on the basis of the current state of the volcano while also taking into account the likely scenario of future unrest.
    Description: Published
    Description: 625-634
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Seismological Monitoring ; Mount Vesuvius ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
    Publication Date: 2020-11-30
    Description: Mt. Vesuvius (southern Italy) is one of the volcanoes with the greatest risk in the World because of its highly explosive eruptive style and its proximity to densely populated areas. The urbanization around Mt. Vesuvius began in ancient times and the impact of eruptions on human activities has been very hard...
    Description: INGV,sezione di Napoli,Osservatorio Vesuviano
    Description: Published
    Description: Tenerife, Canary Islands, Spain
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: open
    Keywords: Seismological Monitoring ; Mount Vesuvius ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Abstract
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  • 3
    Publication Date: 2020-11-30
    Description: On February 27, 2007, the Stromboli volcano, which has usually been characterized by moderate explosive activity, started an effusive eruption with a small lava flow down the NW flank. The permanent broadband network installed on the island allowed the revealing of anomalies in the seismicity before the effusive eruption and for the phenomena to be followed over time, thus obtaining meaningful information about the eruption dynamics. During the effusive phase, a major explosion occurred on March 15, 2007. On that occasion, two strainmeters deployed on the volcano in the previous year recorded a strain increment before the blast. After this explosion, which further destabilized the upper part of the edifice, swarms of Long-Period (LP) and hybrid events were recorded. The characteristics and locations of these events suggest that they were associated with the fracturing processes that affected the summit area of the cone. During the effusive phase, changes in the Very Long Period (VLP) event location were recorded. This type of events accompanied the change in the eruptive style, providing information about the magmatic conduit involved in their seismogenetic processes. The effusive phase stopped on April 2, 2007, and the typical Strombolian activity restarted some months later.
    Description: JCR Journal
    Description: open
    Keywords: Stromboli ; volcano monitoring ; volcano seismicity ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
    Publication Date: 2017-04-04
    Description: We have implemented a method based on an unsupervised neural network to cluster the waveforms of very-long-period (VLP) events associated with explosive activity at the Stromboli volcano (southern Italy). Stromboli has several active vents in the summit area producing together more than 200 explosions=day. We applied this method to investigate the relationship between each vent and its associated VLP explosive waveform. We selected 147 VLP events recorded between November and December 2005, when digital infrared camera recordings were available. From a visual inspection of the infrared camera images, we classified the VLPs on the basis of which vent produced each explosion. We then applied the self-organizing map (SOM), an unsupervised neural technique widely applied in data exploratory analysis, to cluster the VLPs on the basis of their waveform similarity. Our analysis demonstrates that the most recurrent VLP waveforms are usually generated by the same vent. Some exceptions occurred, however, in which different waveforms are associated with the same vent, as well as different vents generating similar waveforms. This suggests that the geometry of the upper conduit-vent system plays a role in shaping the recurring VLP events, whereas occasional modest changes in the source process dynamics produce the observed exceptions.
    Description: Published
    Description: 2449–2459
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli ; Maps ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 05. General::05.01. Computational geophysics::05.01.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
    Publication Date: 2017-04-04
    Description: THE ISTITUTO NAZIONALE DI GEOFISICA E VULCANOLOGIA (INGV) AND THE ITALIAN DEPARTMENT FOR CIVIL DEFENSE (DPC)
    Description: Published
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: open
    Keywords: 3D velocity ; Neapolitan ; volcanic areas ; 04. Solid Earth::04.06. Seismology::04.06.07. Tomography and anisotropy ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: report
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  • 6
    Publication Date: 2017-04-04
    Description: In this article we report on the implementation of an automatic system for discriminating landslide seismic signals on Stromboli island (southern Italy). This is a critical point for monitoring the evolution of this volcanic island, where at the end of 2002 a violent tsunami occurred, triggered by a big landslide. We have devised a supervised neural system to discriminate among landslide, explosion-quake, and volcanic microtremor signals. We first preprocess the data using a compact representation of the seismic records. Both spectral features and amplitude-versus-time information have been extracted from the data to characterize the different types of events. As a second step, we have set up a supervised classification system, trained using a subset of data (the training set) and tested on another data set (the test set) not used during the training stage. The automatic system that we have realized is able to correctly classify 99% of the events in the test set for both explosion-quake/ landslide and explosion-quake/microtremor couples of classes, 96% for landslide/ microtremor discrimination, and 97% for three-class discrimination (landslides/ explosion-quakes/microtremor). Finally, to determine the intrinsic structure of the data and to test the efficiency of our parameterization strategy, we have analyzed the preprocessed data using an unsupervised neural method. We apply this method to the entire dataset composed of landslide, microtremor, and explosion-quake signals. The unsupervised method is able to distinguish three clusters corresponding to the three classes of signals classified by the analysts, demonstrating that the parameterization technique characterizes the different classes of data appropriately.
    Description: Published
    Description: 1230-1240
    Description: reserved
    Keywords: NONE ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 850226 bytes
    Format: application/pdf
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  • 7
    Publication Date: 2017-04-04
    Description: The Colli Albani are a Quaternary volcanic complex located about 15 km SE of Rome, comprised in an area of latitudes 41.6-41.9 N and longitudes 12.5-12.9 E. It has recently developed particular interest in the geophysical community for some peculiar characteristics imputable to a residual volcanic activity. In the framework of a project financed by the Department of the Civil Protection devoted to the study of the Colli Albani deformations, we have recently realized a bathymetric survey of the Albano lake and an airborne laser scanner survey of the Albano and Nemi craters. The present work is composed by two phases. In a first phase the accuracy of the DEM achieved by the laser scanner is verified through a comparison with a GPS kinematic survey. In particular, our aim is to test if the use of DEM in different formats, TIN or Grid, could lead to meaningful differences in terms of accuracy and precision. In a second phase of the work, we merged the LIDAR and bathymetric data with the purpose to achieve a complete digital terrain model of the area that could allow in the next future geo-morphological analyses of the whole volcanic structure.
    Description: Published
    Description: open
    Keywords: LASER SCANNER ; COLLI ALBANI ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 8
    Publication Date: 2017-04-04
    Description: We have analyzed the recent seismicity of Mt. Vesuvius, with particular emphasis on the period 1999-2012. Since 1972 continuous observations with electromagnetic seismometers allowed the compilation of a detailed earthquake catalogue for the station OVO. Furthermore since 1999 another, more complete, catalogue for the station BKE, closer to the crater, is available. The Gutenberg-Richter distribution of magnitudes shows a temporal decrease of the b-value since 1985, with current values close to 1.0. The temporal pattern of the strain release shows a non-stationary behavior with periods of increased release rates (as in 1989-1990, 1995-1996 and 1999-2000). The spatial distribution of the seismicity consists in two main seismogenic volumes, one with hypocenters clustered below the Mt. Vesuvius crater at depths mostly between 1-6 km, and another with hypocenters clustered within the Gran Cono volcanic edifice, with depths above the sea level. We compare the statistical properties of the seismicity occurring within these two volumes and their spatial and temporal patterns. Moreover we analyze the statistical distribution of focal mechanisms for each volume. Our results point to gravity-induced stresses as the source of the shallow seismicity and of a combined effect of crustal heterogeneities, regional stress and hydrothermal dynamics for the deeper seismicity. Finally we discuss possible future developments of the seismic monitoring system in the light of the past and current seismicity.
    Description: Published
    Description: S0442
    Description: 2V. Dinamiche di unrest e scenari pre-eruttivi
    Description: JCR Journal
    Description: open
    Keywords: Mt. Vesuvius ; seismological monitoring ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 9
    Publication Date: 2017-04-04
    Description: Campi Flegrei caldera is located in a very densely populated area. Half of the city of Naples lies within the caldera rims with about 350000 people living on this active volcano. For this reason the surveillance of this volcano requires advanced monitoring techniques in order to forecast even minor eruptions. The area was interested in the period 1982-84 by an unrest crisis with more than 16000 earthquakes and about 2m of ground uplift...
    Description: INGV;Sezione di Napoli,Osservatorio Vesuviano
    Description: Published
    Description: Tenerife, Canary Islands, Spain
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: open
    Keywords: Recent Seismicity ; Campi Flegrei Caldera ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Abstract
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  • 10
    Publication Date: 2017-04-04
    Description: Landslides along the Sciara del Fuoco flank of Stromboli volcano are generally accompanied by c1istinctive seismic signals which can be used for srudying this phenomenon. These signals are characterìzed by a spectral content with higher frequencies and a wider band than the typical explosion quakes and volcanic tremor signals which are continuously recorded at Stromboli. Furthermore their amplirude envelope usually shows a cigar-like shape. These two fearures make the detection of such signals quite easy. The detection of landslides at Stromboli has shown to be an important shortterm precursor of effusive eruptions. Before the Feb. 27th 2007 eruption, the opening of the effusive vents was preceded by few hours oI increased occurrence of landslide signals (Martini et al., 2007). Furthermore since the Sciara del Fuoco has shown significant instabilities during the 2002-2003 eruption, the automatic detection of landslide signals is an important monitoring tool for notifying variations in the stability of this flank. We propose a technique based on a Multi Layer Perceptron (MLP) neural network which has shown excellent performances. The network is composed of two layer of neurons, the hidden and the output. The hidden layer is composed of 4 neurons while the output layer is composed by a single neuron whose output value ranges between Oand 1, with values higher than a given threshold (e.g. 0.5) meaning positive detection. The continuous seismic signals are analysed using moving windows of 24 s, with an overlap of 12 s. For each of these windows the neural output is computed. The waveforms of each time window are parametrized using both their spectrogram and their amplirude envelope. The spectrogram is described using the Linear Preclictive Cocling (L'PC) technique which allows to represent the spectral content using a limited number of coefficients. The whole signal is c1ivided into 8 sub-windows of 5.12 s length, with an overlapping of 2.56 s. For each sub-window we compute 6 LPC coefficients, so each spectrogram is described by only 48 coefficients. The amplirude envelope is defined by computing the c1ifference between the maximum and minimum value over 1 s sub-windows obtaining 24 coefficients. In conclusion we use an input vector composed of 72 elements (48+24). This vector has shown to be an efficient and compact representation of the raw signal (composed of 1200 samples) (Esposito et al. 2006). The dataset used for determining the network parameters is composed of 537 signals, c1ivided in two classes: 267 landslide signals and 270 other signals (explosions and tremor). The classification of these signals has been performed by analysts. The training is carried out using subsets of 5/8 of the total dataset. The testing subsets are composed by the remaining 3/8. The network has shown a performance of about 98.7%. This value is an average over 6 random permutations of the dataset. A preliminary real-rime automatic system has already been implemented. This system performs continuous analysis of the seismic signals, publishing them on internal web pages. It allows a detection of the landslides and a comparison with the past activity on arbitrary rime intervals.
    Description: Published
    Description: Nicolosi (Catania)
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 3.1. Fisica dei terremoti
    Description: 3.6. Fisica del vulcanismo
    Description: open
    Keywords: Automatic detection ; landslides ; Stromboli ; neural network analysis ; seismic signals ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.06. Seismic methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.06. Seismology::04.06.10. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Conference paper
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