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Montalto, Placido
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Montalto, Placido
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placido.montalto@ingv.it
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staff
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23489549800
66 results
Now showing 1 - 10 of 66
- PublicationRestrictedVolcanic tremor and long period events at Mt. Etna: Same mechanism at different rates or not?(2022)
; ; ; ; ; ; ; Volcanic tremor and long period (LP) events are typical seismic signals recorded on active volcanoes and are characterized by different durations, longer than minutes and a few seconds - tens of seconds for the former and latter, respectively. As they share the same frequency content, they are often grouped together in the literature and referred to by the unique name of LP seismicity. The common spectral features, together with observations in some volcanoes of individual LP events merging to form volcanic tremor, led to hypotheses that LP events and volcanic tremor share the same source mechanism. However, it is still open to debate whether volcanic tremor can be considered a simple coalescence of LP events or not. In this work, to help answer such a question, we analysed volcanic tremor and LP events recorded at Mt. Etna during the period February 2019–June 2020, characterized by minor eruptive activity, varying from weak ash emission to explosive and effusive eruptions at all the summit craters. Results from spectral, amplitude and location analyses, as well as the different scaling laws explaining the distributions of the duration/number of events versus size, led us to infer that LP events and volcanic tremor at Mt. Etna are not due to a common source mechanism.191 92 - PublicationRestrictedTime-space variation of volcano-seismic events at La Fossa (Vulcano, Aeolian Islands, Italy): new insights into seismic sources in a hydrothermal system(2010)
; ; ; ; ; ; ;Alparone, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cannata, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Gambino, S. ;Gresta, S.; DIpartimento di Scienze Geologiche, Università degli Studi di Catania ;Milluzzo, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Montalto, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ;; ; We investigated the relationship between volcano-seismic events, recorded at La Fossa crater of Vulcano (Aeolian Islands, Italy) during 2004-2006, and the dynamics of the hydrothermal system. During the period of study, three episodes of increasing numbers of volcano-seismic events took place at the same time as geothermal and geochemical anomalies were observed. These geothermal and geochemical anomalies have been interpreted as resulting from an increasing deep magmatic component of the hydrothermal fluids. Three classes of seismic events (long period, high frequency and monochromatic events), characterised by different spectral content and various similarity of the waveforms, have been recognised. These events, clustered mainly below La Fossa crater area at depths of 0.5–1.1 km b.s.l., were space-distributed according to the classes. Based on their features, we can infer that such events at Vulcano are related to two different source mechanisms: (1) fracturing processes of rocks and (2) resonance of cracks (or conduits) filled with hydrothermal fluid. In the light of these source mechanisms, the increase in the number of events, at the same time as geochemical and geothermal anomalies were observed, was interpreted as the result of an increasing magmatic component of the hydrothermal fluids, implying an increase of their flux. Indeed, such variation caused an increase of both the pore pressure within the rocks of the volcanic system and the amount of ascending fluids. Increased pore pressures gave rise to fracturing processes, while the increased fluid flux favoured resonance and vibration processes in cracks and conduits. Finally, a gradual temporal variation of the waveform of the hybrid events (one of the subclasses of long period events) was observed, likely caused by heating and drying of the hydrothermal system.301 32 - PublicationRestrictedOn the time-scale of thermal cycles associated with open-vent degassing(2012-08-08)
; ; ; ; ; ; ;Spampinato, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Oppenheimer, C. ;Cannata, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Montalto, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Salerno, G. G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Calvari, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ;; ; ; Thermal imagery obtained with portable infrared cameras is widely used to track and measure volcanic phenomena. In the case of explosive eruptions, both air and ground-based thermal monitoring have enabled collection of data streams from relatively safe distances. Analysis of these data have enabled the characterisation of different explosive regimes, parameterisation of eruptive plumes, and assessment on the dynamics occurring in the shallow system. Here we explore the suitability of infrared imagers for investigating the short time scale eruptive behaviour of three basaltic volcanoes. We present high-time resolution thermal image data-sets recorded at Etna, Stromboli and Kīlauea volcano. At the time of observations, all three exhibited pulsed degassing. Signal processing of the mean apparent temperature time-series highlights four broad classes of cyclic temperature changes at the three volcanoes based on characteristic time-scales revealed in the periodograms: (1) <15 s, (2) ~20-50 s, (3) ~1-10 min, and (4) 12–90 min. Based on previous studies and integrating time-series results with qualitative visible and thermal observations and, in case of Kīlauea, also with SO2 column amounts in the plume, we hypothesise that short cycles relate mainly to bursting of overpressured gas bubbles at the magma surface, while long cycles might be associated with mechanisms of gas slug formation and ascent, and to the emplacement and drainage of a lava lake. At Kīlauea, slow fluctuations may reflect periodic variations of the lava lake surface level. The data from all three volcanoes reveal superimposition of degassing cycles of different frequencies, suggesting link through common magmatic processes and physical properties.544 23 - PublicationOpen AccessJoint analysis of infrasound and seismic signals by cross wavelet transform: detection of Mt. Etna explosive activity(2013)
; ; ; ;Cannata, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Montalto, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Patanè, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; The prompt detection of explosive volcanic activity is crucial since this kind of activity can release copious amounts of volcanic ash and gases into the atmosphere, causing severe dangers to aviation. In this work, we show how the joint analysis of seismic and infrasonic data by wavelet transform coherence (WTC) can be useful to detect explosive activity, significantly enhancing its recognition that is normally done by video cameras and thermal sensors. Indeed, the efficiency of these sensors can be reduced (or inhibited) in the case of poor visibility due to clouds or gas plumes. In particular, we calculated the root mean square (RMS) of seismic and infrasonic signals recorded at Mt. Etna during 2011. This interval was characterised by several episodes of lava fountains, accompanied by lava effusion, and minor strombolian activities. WTC analysis showed significantly high values of coherence between seismic and infrasonic RMS during explosive activity, with infrasonic and seismic series in phase with each other, hence proving to be sensitive to both weak and strong explosive activity. The WTC capability of automatically detecting explosive activity was compared with the potential of detection methods based on fixed thresholds of seismic and infrasonic RMS. Finally, we also calculated the cross correlation function between seismic and infrasonic signals, which showed that the wave types causing such seismo-acoustic relationship are mainly incident seismic and infrasonic waves, likely with a common source.351 780 - PublicationOpen AccessSviluppo di un software per la detezione e classificazione in near real-time degli eventi sismo-vulcanici(2016-02-22)
; ; ; ; ; ; ; ;Cannata, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Milluzzo, V.; ENI - Angola ;Aliotta, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cassisi, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Gambino, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Montalto, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Prestifilippo, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; ; ; 211 168 - PublicationRestrictedProbability hazard map for future vent opening at Etna volcano (Sicily, Italy).(2014-10-29)
; ; ; ; ; ; ;Alfonso, Brancato; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Mauro, Coltelli; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Placido, Montalto; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Domenico, Patanè; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cristina, Proietti; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Danila, Scandura; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; ; Mount Etna is a composite stratovolcano located along the Ionian coast of eastern Sicily. The frequent occurrence of flank eruptions (at an interval of years), mostly concentrated along the NE, S and W rift zones leads to a high volcanic hazard that, linked with intense urbanization, poses a high volcanic risk. In the framework of the project PON SIGMA (Integrated Cloud-Sensor System for Advanced Multirisk Management), we develop a near real-time computer-assisted analysis and probabilistic evaluations that provides the identification of the areas prone to the highest vent opening hazard. A longterm volcanic hazard assessment, mainly based on the past flank activity of the Mt. Etna volcano, is the basic tool for the evaluation of this risk. Then, a reliable forecast of where an impending eruption will occur is needed. The use of a code such BET_EF (Bayesian Event Tree_Eruption Forecasting) delivers a long-term hazard map, that, if additional data are provided, switches into a short-term future vent opening map. The present application is based on incoming seismic and ground deformation data. Analytic inversion of high frequencies deformation data is performed to find the key parameters of a magmatic source in an elastic, isotropic and homogeneous half-space. Seismic data allow us to set the boundary of the investigated area. The inversion is performed by using the genetic algorithms (GAs) approach, a well-known search technique widely used to solve optimization problems and categorized as global search heuristics (Goldberg, 1989). Hence the magmatic source is located, a forward model is computed to evaluate the deformation field over Mt. Etna surface. Therefore, for each cell, the displacement vector modulus is estimated and the density probability function is calculated. A higher probability value matches with the cells with larger modulus, whereas lower estimate is found where the modulus is close to zero, being the sum of the probability values normalized to one over the investigated area. We modelled the final intrusion of the May 2008 – July 2009 flank eruption at Mt. Etna, whose onset was preceded by an intense seismic swarm and marked by ground deformation recorded at GPS stations. The future vent forecast highlights the area with higher probability, increasing the difference in relative values between that zone and the rest of the volcano edifice. It is worthy notice that a good accordance is evident if the highest probability area is compared with the real vent occurrence.231 19 - PublicationOpen AccessPrototipo di un portale per la distribuzione dei dati dell’Osservatorio Etneo basato sulla piattaforma Zenodo(2022-11-23)
; ; ; ; ; ; ; ; ; 46 66 - PublicationOpen AccessSEISMICOFFICE, UNA SUITE SOFTWARE PER L’ANALISI E LA GESTIONE DEI DATI SISMICI(2013)
; ; ; ; ;Montalto, Placido; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Aliotta, Marco; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cassisi, Carmelo; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cannata, Andrea; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; 182 145 - PublicationOpen AccessSistema di elaborazione automatica dei segnali infrasonici al Monte Etna(2016-02-23)
; ; ; ; ; ; ; ; ;Cannata, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Privitera, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Sciotto, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Scuderi, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Aliotta, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cassisi, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Montalto, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Rapidarda, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; ; ; ; 261 179 - PublicationOpen AccessAdvances in the study of geophysical signals from Mt. Etna volcano.(2009)
; ; ; ; ; ; ;Cannata, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Carbone, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Di Grazia, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Montalto, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Patanè, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Zuccarello, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; ; ; ; ; ; ; ; ;Bean, C. J.; School of Geological Sciences, University College Dublin ;Braiden, A. K.; School of Geological Sciences, University College Dublin ;Lokmer, I.; School of Geological Sciences, University College Dublin ;Martini, F.; School of Geological Sciences, University College Dublin ;O'Brien, G. S.; School of Geological Sciences, University College Dublin,; ; ; ; Long-period seismic signals, including LP events and tremor, observed on many volcanoes worldwide, may play a crucial role in the forecasting of volcanic eruptions as these signals are direct indicators of sub-surface magma dynamics. Their location is widely agreed to be useful for mapping the extension and geometry of the plumbing system and also for quantifying pressure transients caused by resonance or movement of fluids along the conduits. At Mt. Etna detailed investigations on these signals started systematically only after the installation of a broad-band seismic network (since 2003). Thereafter, we present the main results recently obtained on this volcano by analysing tremor, LP and VLP events during two eruptive episodes in the second half of 2007. We also discuss results of cross analysis performed between tremor and gravity sequences acquired simultaneously at Mt. Etna during the 2002-03 eruption and during the December 2005-January 2006 period of quiescence. We detected common anomalies which are indicative of a quasi-closed system, becoming progressively enriched in volatiles. These studies, carried out in the framework of the VOLUME Project, provide new insight into the shallow plumbing system of Etna and grant valuable tools for volcanic hazard forecasting and risk mitigation.227 177