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Cristaldi, Antonio
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Cristaldi, Antonio
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Cristaldi, Antonino
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- PublicationOpen AccessThe 23–24 March 2021 lava fountain at Mt Etna, Italy(2024)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; In 2021, more than 50 paroxysmal episodes occurred at the South-East Crater (SEC) of Mt Etna, Italy. The 23–24 March lava fountain was one of the longest episodes and began with weak Strombolian explosions, gradually transitioning to lava fountaining. The eruption intensity then dropped more slowly than in previous episodes, resulting in pulsating Strombolian explosions dominated by ash emission. Thirty-four tephra samples were used to reconstruct the fallout dispersal and estimate the total erupted mass. Grain size, textural, petrological and geochemical analyses indicate different features and were compared with the gas phase ( SO2 and HCl) in the volcanic plume. By applying stochastic global optimization to simulations of the temporal evolution of the eruption column height and tephra dispersal and deposition, the total erupted mass retrieved (6.76 × 108 kg) matches well the total erupted mass estimation by the ground-based deposit (8.03 ± 2.38 × 108 kg), reducing the column height throughout the episode from 6.44 to 4.5 km above sea level and resulting in a mass eruption rate ranging from 1.96 × 105 to 8.18 × 103 kg/s. The unusual duration of the March episode and the characteristics of the erupted products point to the change in explosive style and magma fragmentation from fountaining to ash emission phases, associated with a slower magma supply inducing a change in magma rheology and a final, prolonged ash generation. Furthermore, this study showed that using observational data and the variation in eruption source parameters for numerical simulations can improve the accuracy of predicting the dispersal plume, thus mitigating the potential impact of longer paroxysmal episodes.177 9 - PublicationOpen AccessCharacterizing high energy explosive eruptions at Stromboli volcano using multidisciplinary data: An example from the 9 January 2005 explosion(2008)
; ; ; ; ;Andronico, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Corsaro, R. A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cristaldi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Polacci, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia; ; ; Stromboli is well known for its persistent, normal explosive activity, consisting of intermittent, mild to moderate, Strombolian explosions that typically occur every 10–20 min. All tephras erupted during this activity usually fall back into the crater terrace, and consist of volatile-poor scoriae fed by Highly Porphyritic (HP) magma. More occasionally, large explosions or “paroxysms” eject a greater quantity of tephra, mainly consisting of HP scoriae and pumice clasts of Low Porphyritic (LP) magma, but also including large lithic blocks. In addition to this activity, between 2004 and 2006 high energy explosions, displaying an intermediate eruptive style between that of normal and paroxysmal explosions in terms of column height, duration and tephra dispersal, were observed to occur at a frequency of one to eight events per year. While many volcanological, geochemical and geophysical studies have focused in the last few years on the two endmembers of activity, i.e. normal or paroxysmal, a detailed investigation on these intermediate types of events has not been carried out yet. Here we report of a study on the 9 January 2005 explosion, one of the high energy explosions during which the main fountaining phase lasted nearly a minute causing ejection of coarse bombs up to a height of 120 m, and of ash and lapilli to N200 m. An accompanying ash plume rose up to 500 m at the end of the explosion. We present a multidisciplinary approach that integrates the results from analysis of live-camera images with compositional and textural characterization of the erupted products. Major element composition of glassy groundmass and 3D views of textures in the erupted scoriae support the hypothesis based on volcanological observations that this explosion falls between normal and paroxysmal activity, for which we use the term “intermediate”. By comparing the video-camera images of the 9 January 2005 explosion with volcanological features of other high energy explosions that occurred at Stromboli between June 2004 and October 2006, we find that three additional events can be considered intermediate explosions, suggesting that this type of activity may be fairly common on this volcano. The results of this study, although preliminary given our limited dataset, clearly indicate that the methodology used here can be successfully applied to better define the range of eruptive styles typifying the normal explosive activity, potentially improving our capability of eruption forecasting and assessing volcanic hazard at Stromboli.199 1268 - PublicationOpen AccessMagma Budget From Lava and Tephra Volumes Erupted During the 25-26 October 2013 Lava Fountain at Mt Etna(2018)
; ; ; ; ; ; ; ; ; ; ; ; ; Determining the volume of the various types of products of a highly frequent active volcano can be very difficult, especially if most of them are deposited on a growing volcanic cone. The New South-East Crater (NSEC) of Mt Etna, Italy, may be considered one of the best case studies because of tens of paroxysmal episodes which it produced in the last few years. On 25-26 October 2013, a lava fountain at the NSEC produced magma jets up to 500 m high, a maximum similar to 8 km high column, a multilobate lava flow field 1.3-1.5 km long, and almost 30 m of growth in height of the NSEC cone. Mapping of explosive and effusive deposits allowed us to calculate the total volume of erupted products, including lava flows, proximal, and distal tephra fallout, and the amount of coarse pyroclastics on the cone. The estimation of the latter products was also confirmed subtracting digital elevation models (DEMs) obtained at different stages of the NSEC growth. Results show that the volume of tephra fallout away from the cone was only <5 % of the total erupted magma, while the total volume of pyroclasts (distal plus proximal fallout) was about a third of the lava volume. Our analysis suggests that, at least for the studied event, three fourth of the involved magma was already partially degassed and thus emitted as lava flows. Hence, the main distinctive character of lava fountains at Etna, i.e., formation of eruption column and propagation of tephra-laden volcanic plumes to tens of km away from the volcano, would not contribute significantly to the final budget of erupted magma of the 25-26 October 2013 eruption. We therefore propose that the same magma dynamics, i.e., similar magma distribution, probably occur also during most of the common lava fountain episodes. Finally, we infer that quantifying the magma budget from lava and tephra volumes erupted during the 25-26 October lava fountain can give new insights into the mechanisms driving the eruptive behavior of Etna during paroxysmal activity from the summit craters, and provide useful indications also in terms of volcanic hazard.1820 33 - PublicationRestrictedAdvances in the Study of Volcanic Ash(2007-06-12)
; ; ; ; ; ; ; ;Taddeucci, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Scarlato, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Andronico, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cristaldi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Buettner, R.; Uni-Wuerzburg ;Zimanowski, B.; Uni-Wuerzburg ;Kueppers, U.; Uni-Azores; ; ; ; ; ;Every month, small-scale explosive volcanic eruptions inject more than a million cubic meters of ash into Earth’s atmosphere [Simkin and Siebert, 2000]. Of all the troubles caused by this relatively mild volcanic activity, ashfall is by far the longest-reaching one, mantling the volcano slopes and surroundings with a slippery, heavy, unhealthy, and snow-like but Sun-resistant cover. Volcanic ash is composed of pyroclasts (fragments generated and emplaced by explosive eruptions) smaller than 2 millimeters, which are easily transported by wind and have a high surface-to-volume ratio. These same features, however, also allow safe collection of the ash away from the volcano. Such pyroclasts bear the signature of the fragmentation and dispersal processes they have experienced during eruption and transport. Thus, volcanic ash provides sample material well suited for studying quasi time correlated eruption dynamics [Taddeucci et al., 2002]. Here we illustrate how current research projects funded by the Italian Department for Civil Protection combine new sampling, analytical, and experimental techniques to maximize the extraction of useful information from basaltic volcanic ash.205 34 - PublicationOpen AccessAutomatic Classification of eruptive events by the VAMOS system(1999-09-14)
; ; ; ; ; ; ;Bertucco, L.; Dipartimento Elettrico, Elettronico e Sistemistico, Università di Catania ;Coltelli, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cristaldi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Mangiagli, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Nunnari, G.; Dipartimento di Ingegneria Elettrica, Elettronica e Informatica dell'Università degli Studi di Catania ;Pecora, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; ; An automatic system named VAMOS (Volcanic Activity MOnitoring System) for monitoring volcanic activity at Mt. Etna and Stromboli volcanoes, is at the present under test at the data collection center at IIV (Istituto Internazionale di Vulcanologia, CNR, Catania). This system allows automatic recognition of volcanic activity by on-line processing of images collected by the surveillance cameras positioned close to the summit crater of two above mentioned volcanoes which are worldwide known to be characterized by a persistent eruptive activity. Based on this automatic system, a new software tool to extract quantitative information from collected images is now under developing. Several tasks have been planned to solve by using this tool such as the automatic classification of recorded events and the computation of relaxed energy based on stereo-vision and thermal images. One of the first result of the undertaken research activity has been the automatic classification of the type of volcanic events and the localization of the eruptive event.183 112 - PublicationRestrictedShifting styles of basaltic explosive activity during the 2002-03 eruption of Mt. Etna, Italy(2009-03-10)
; ; ; ; ;Andronico, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cristaldi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Del Carlo, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italia ;Taddeucci, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; The 2002–03 flank eruption of Etna was characterized by two months of explosive activity that produced copious ash fallout, constituting a major source of hazard and damage over all eastern Sicily. Most of the tephra were erupted from vents at 2750 and 2800 m elevation on the S flank of the volcano, where different eruptive styles alternated. The dominant style of explosive activity consisted of discrete to pulsing magma jets mounted by wide ash plumes, which we refer to as ash-rich jets and plumes. Similarly, ash-rich explosive activity was also briefly observed during the 2001 flank eruption of Etna, but is otherwise fairly uncommon in the recent history of Etna. Here, we describe the features of the 2002–03 explosive activity and compare it with the 2001 eruption in order to characterize ash-rich jets and plumes and their transition with other eruptive styles, including Strombolian and ash explosions, mainly through chemical, componentry and morphology investigations of erupted ash. Past models explain the transition between different styles of basaltic explosive activity only in terms of flow conditions of gas and liquid. Our findings suggest that the abundant presence of a solid phase (microlites) may also control vent degassing and consequent magma fragmentation and eruptive style. In fact, in contrast with the Strombolian or Hawaiian microlite-poor, fluidal, sideromelane clasts, ash-rich jets and plumes produce crystal-rich tachylite clasts with evidence of brittle fragmentation, suggesting that high groundmass crystallinity of the very top part of the magma column may reduce bubble movement while increasing fragmentation efficiency.124 29 - PublicationOpen AccessA new approach for evaluating the strombolian type activity(2003-09-07)
; ; ; ; ; ;Coltelli, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cristaldi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Mangiagli, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Nunnari, G.; Dipartimento di Ingegneria Elettrica, Elettronica e Informatica dell'Università degli Studi di Catania ;Pecora, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; Volcanoes represent one of the most important application fields for risk mitigation techniques (Mc Guire, Kilburn, and Murray, Eds, 1995) due to the ingent damages and casuality. This paper deals with a monitoring system that could be successful used for risk mitigation related to forecast paroxysmal explosions of strombolian type. The typical activity of Stromboli volcano consists of intermittent mid explosions lasting a few seconds, which take place at different vents and at variable intervals, the most common time interval being 10-20 minutes (Chouet, Hamisevicz, and McGetchin, 1974; Blackburn, Wilson, and Sparks, 1976). However the routine activity can be interrupted by more violent paroxysmal explosions, that eject m-sized scoriaceous bombs and lava blocks to a distance of several hundreds of meters from active vents. On average, one or two paroxysmal explosions occurred per year over the past century, buth this statistic may be underestimated in absence of continuous monitoring. For this reason from summer 1996 a remote surveillance camera works on Stromboli recording continuously the volcanic activity. It is located on Pizzo Sopra la Fossa, 100 metres above the crater terrace where are the active vents. Moreover, from September 2001 an on-line image analyzer system referred to as VAMOS (Volcanic Activity MOnitoring System) operates detection and classification of explosive vents in real-time. Using VAMOS it is possible to identify changes in the explosive activity trend that could precede a particular eruptive event, like paroxysmal explosions, fire fountains, lava flows. Since the camera installation up to present, several explosions occurred at the different craters and the parameterization in classes of intensity for each explosion on the base of tephra dispersion and kinetic energy have been made. The analysis include the counting of the explosions occurred at the different craters and the parameterisation in classes of intensity for each explosion on the base of tephra dispersion and, in generic sense, of the kinetic energy released. The plot of dissipated energy by each crater versus time seems to exhibit a cyclic behaviour with max and min explosive activity ranging from a few days to a month. Often the craters show opposite trends so when the activity decreases in a crater, increases in the other. Before every paroxismal explosion recorded, the crater that produced the event decreased and then stopped its activity from a few days to weeks before. The other crater tried to compensate increasing its activity and when it declined the paroxysmal explosion occurred suddenly at the former site (Coltelli, and Cristaldi, 2003). The system has automatically recorded and analysed the change in energetic trend that proceded the 20 October 2001 paroxysmal explosion that killed a woman and the strong explosive activity that preceded the onset of 28 December 2002 lava flow eruption.181 158 - PublicationOpen AccessModeling Eruption Source Parameters by Integrating Field, Ground-Based, and Satellite-Based Measurements: The Case of the 23 February 2013 Etna Paroxysm(2018)
; ; ; ; ; ; ; ; ; ; ;Volcanic plumes from Etna volcano (Italy) are governed by easterly winds driving ash over the Ionian Sea. The limited land tephra deposit makes total grain‐size distribution (TGSD) assessment and its fine ash fraction highly uncertain. On 23 February 2013, a lava fountain produced a ~9‐km‐high column above sea level (a.s.l.). The atypical north‐easterly wind direction dispersed the tephra from Etna to the Puglia region (southern Italy) allowing sampling up to very distal areas. This study uses field measurements to estimate the field‐based TGSD. Very fine ash distribution (particle matter below 10 μm—PM10) is explored parameterizing the field‐TGSD through a bi‐lognormal and bi‐Weibull distribution. However, none of the two latter TGSDs allow simulating any far‐traveling airborne ash up to distal areas. Accounting for the airborne ash retrieved from satellite (Spinning Enhanced Visible and Infrared Imager), we proposed an empirical modification of the field‐based TGSD including very fine ash through a power law decay of the distribution. The input source parameters are inverted by comparing simulations against measurements. Results suggest a column height of ~8.7 km a.s.l., a total erupted mass of ~4.9 × 109 kg, a PM10 content between 0.4 and 1.3 wt%, and an aggregate fraction of ~2 wt% of the fine ash. Aerosol optical depth measurements from the AErosol RObotic NETwork are also used to corroborate the results at ~1,700 km from the source. Integrating numerical models with field, ground‐based, and satellite‐based data aims at providing a better TGSD estimation including very fine ash, crucial for air traffic safety.457 38 - PublicationRestrictedEruption dynamics and tephra dispersal from the 24 November 2006 paroxysm at South-East Crater, Mt Etna, Italy(2014)
; ; ; ; ; ; ;Andronico, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Scollo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Lo Castro, M. D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cristaldi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Lodato, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Taddeucci, J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; ; Between 30 August and 15 December 2006,Mt Etna, Italy, underwent both effusive and explosive activity which took place fromthe South-East Crater, one of its summit craters. Several paroxysmal episodes followed in succession, separated by a fewdays of minor activity and characterised by dissimilar explosive style and intensity. Here, we report one of the most studied and powerful episodes, which started early in the morning on 24 November 2006 and lasted about 13 h. Excellent weather conditions enabled reconstructing in detail the onset and evolution of the eruptive phenomena both by live-camera recordings and direct observations. The explosive activity consisted of powerful Strombolian activity alternating with short periods of lava fountains. A weak volcanic plume rose up to ~2 km above the volcanic vent, followed by tephra fallout which covered the SE and S flanks of Etna. Campaigns allowed collecting about 40 tephra samples and mapping the fallout deposit. The clockwise shifting of the volcanic plume during the eruption caused the different timing of the fallout on the ground, thus widening the dispersal area. Voronoi's method was used to evaluate: i) the total grain-size distribution, indicating that the fallout deposit peaked at 1 ϕ, and, for the first time at Etna, ii) the total componentry distribution, finding thatmost of the particles were lithics, with a low proportion of juvenile vs. lithics (34:65). The total erupted mass was estimated ~1.9 × 108 kg, corresponding to a mass eruption rate of ~5 × 103 kg s−1. Physical parameters and textural features of the erupted products suggest that the 24 November 2006 explosive event may be classified as small-sized in the recent history of Etna, and that the eruptive dynamicwasmainly governed by magma/gas decoupling, which produced relatively fine-grained fallout deposits containing unusual elongated sideromelane ash particles.316 26 - PublicationRestrictedRepresentivity of incompletely sampled fall deposits in estimating eruption source parameters: a test using the 12–13 January 2011 lava fountain deposit from Mt. Etna volcano(2014-09-04)
; ; ; ; ;Andronico, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Scollo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Lo Castro, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Cristaldi, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; The Southeast Crater (SEC) of Mt. Etna, Italy, is renowned for its high activity, mainly long-lived eruptions consisting of sequences of individual paroxysmal episodes which have produced more than 150 eruptive events since 1998. Each episode typically forms eruption columns followed by tephra fallout over distances of up to about 100 km from the vent. One of the last sequences consisted of 25 lava fountaining events, which took place between January 2011 and April 2012 from a pit-vent on the eastern flank of the SEC and built a new scoria cone renamed New Southeast Crater. The first episode on 12–13 January 2011 produced tephra fallout which was unusually dispersed toward to the South extending out over the Mediterranean Sea. The southerly deposition of tephra permitted an extensive survey at distances between ~1 and ~100 km, providing an excellent characterization of the tephra deposit. Here, we document the stratigraphy of the 12–13 January fallout deposit, draw its dispersal, and reconstruct its isopleth map. These data are then used to estimate the main eruption source parameters. The total erupted mass (TEM) was calculated by using four different methodologies which give a mean value of 1.5 ± 0.4 × 108 kg. The mass eruption rate (MER) is 2.5 ± 0.7 × 104 kg/s using eruption duration of 100 min. The total grain-size (TGS) distribution, peaked at −3 phi, ranges between −5 and 5 phi and has a median value of −1.4 phi. Further, for the eruption column height, we obtained respective values of 6.8–13.8 km by using the method of Carey and Sparks (1986) and 3.4 ± 0.3 km by using the methods of Wilson and Walker (1987), Mastin et al. (2009), and Pistolesi et al. (2011) and considering the mean value of MER from the deposit. We also evaluated the uncertainty and reliability of TEM and TGS for scenarios where the proximal and distal samples are not obtainable. This is achieved by only using a sector spanning the downwind distances between 6 and 23 km. This scenario is typical for Etna when the tephra plume is dispersed eastward, i.e., in the prevailing wind direction. Our results show that, if the analyzed deposit has poorer sample coverage than presented in this study, the TEM (3.4 × 107 kg) is 22 % than the TEM obtained from the whole deposit. The lack of the proximal (<6 km) deposit may cause more significant differences in the TGS estimations.121 18