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Pecora, Emilio
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Pecora, Emilio
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emilio.pecora@ingv.it
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- PublicationOpen AccessLa rete di telerilevamento video dell’Etna(2002-04-24)
; ;Pecora, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia78 125 - PublicationRestrictedThe exceptional activity and growth of the Southeast Crater, Mount Etna (Italy), between 1996 and 2001(2006)
; ; ; ; ;Behncke, B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Neri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Pecora, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Zanon, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; Between 1971 and 2001, the Southeast Crater was the most productive of the four summit craters of Mount Etna, with activity that can be compared, on a global scale, to the opening phases of the Pu‘u ‘Ō‘ō-Kūpaianaha eruption of Kīlauea volcano, Hawai‘i. The period of highest eruptive rate was between 1996 and 2001, when near-continuous activity occurred in five phases. These were characterized by a wide range of eruptive styles and intensities from quiet, non-explosive lava emission to brief, violent lava-fountaining episodes. Much of the cone growth occurred during these fountaining episodes, totaling 105 events. Many showed complex dynamics such as different eruptive styles at multiple vents, and resulted in the growth of minor edifices on the flanks of the Southeast Crater cone. Small pyroclastic flows were produced during some of the eruptive episodes, when oblique tephra jets showered the steep flanks of the cone with hot bombs and scoriae. Fluctuations in the eruptive style and eruption rates were controlled by a complex interplay between changes in the conduit geometry (including the growth of a shallow magma reservoir under the Southeast Crater), magma supply rates, and flank instability. During this period, volume calculations were made with the aid of GIS and image analysis of video footage obtained by a monitoring telecamera. Between 1996 and 2001, the bulk volume of the cone increased by ~36×106 m3, giving a total (1971– 2001) volume of ~72×106 m3. At the same time, the cone gained ~105 m in height, reaching an elevation of about 3,300 m. The total DRE volume of the 1996–2001 products was ~90×106m3. This mostly comprised lava flows (72×106 m3) erupted at the summit and onto the flanks of the cone. These values indicate that the productivity of the Southeast Crater increased fourfold during 1996–2001 with respect to the previous 25 years, coinciding with a general increase in the eruptive output rates and eruption intensity at Etna. This phase of intense summit activity has been followed, since the summer of 2001, by a period of increased structural instability of the volcano, marked by a series of important flank eruptions.283 41 - PublicationOpen AccessApplicazioni delle telecamere termiche Flir A 40 M e Flir 320 M al monitoraggio di Stromboli e dell’Etna(2004)
; ; ;Pecora, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Biale, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; 150 176 - PublicationOpen AccessMisura di alcuni parametri fisici dell’attività esplosiva dell’Etna durante l’eruzione 2002-2003 mediante l’utilizzo di una telecamera infrarosso(2006)
; ;Pecora, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia109 133 - PublicationOpen AccessMonitoraggio video dei vulcani attivi siciliani(2002-09-06)
; ; ;Pecora, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Coltelli, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; 72 171 - PublicationOpen AccessDynamics of low energy explosive activity at Stromboli volcano (Aeolian Islands, Italy)(2007-07-02)
; ; ; ;Zanon, V.; University of the Azores; University of the Azores, Ponta Delgada ;Neri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Pecora, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; Twenty low-energy (0.0077 0.625 kgs-1) explosions from the Northeast Crater of Stromboli Volcano, recorded by a thermal camera, were studied in detail to better understand their dynamics. Each single burst consists of three different jets of different material which come one after another: at first, cold vapour flashes above the crater, expands and then disappears within 0.6 s after the onset of the explosion, at a velocity of 40-113 ms-1. This air shock wave is immediately followed by the expansion of a jet of hot magmatic gas, at a velocity of 35-75 ms-1. Colder coarse tephra (bombs and scoriae) appear about 1.6-2 s after the onset of explosion, moving at a reduced velocity (28-60 ms-1). Further on, some of these data were utilized to calibrate a set of flow simulation in a 220-260-m-long conduit, which validates the model of slug flow for these kinds of eruptions. Finally, coupling all the collected data with the stratigraphy of the volcano, we hypothesized that a physical barrier might be responsible for the formation of slugs of gas and their ascent toward the surface at regular intervals. This barrier acts as a siphon and seems to be generated by the displacement of the upper conduit due to summit instability. This model justifies the ~constant interval between explosions, the insensitivity of this behavior to the occurrence of effusive episodes and highly explosive events, as well as the generation of fairly constant petrochemical characteristics of the magma which is commonly erupted, with time.127 149 - PublicationOpen AccessAborted eruptions at Mt. Etna (Italy) in spring 2007 unveiled by an integrated study of gas emission and volcanic tremor(Geophysical Research Abstracts, 2012-04-22)
; ; ; ; ; ; ; ;Falsaperla, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Behncke, B.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Giammanco, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Neri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Langer, H.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Pecora, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Salerno, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; ; ; In spring 2007, a sequence of paroxysmal episodes took place at the Southeast Crater of Mt. Etna, Italy. Eruptive activity, characterised by Strombolian explosions, lava fountains, emission of lava flows and tephra, were all associated with an outstanding increase in the amplitude of volcanic tremor. In periods of quiescence between the eruptive episodes, recurring phases of seismic unrest were observed in forms of small temporary enhancements of the volcanic tremor amplitude, even though none of them culminated in eruptive activity. Here, we present the results of an integrated geophysical and geochemical data analysis encompassing records of volcanic tremor, thermal data, plume SO2 flux and radon over two months.We conclude that between February and April 2007, magma triggered repeated episodes of gas pulses and rock fracturing, but failed to reach the surface. Our multidisciplinary study allowed us to unveil these ‘aborted’ eruptions by investigating the long-temporal evolution of gas measurements along with seismic radiation. Short-term changes were additionally highlighted using a method of pattern classification based on Kohonen Maps and Fuzzy Clustering applied to volcanic tremor and radon data.329 79 - PublicationOpen AccessLong-term gas observations track the early unrest phases of open-vent basaltic volcanoes(2021-04-26)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ; ; ;; ; At open-vent basaltic volcanoes, resolving the activity escalation that heralds larger, potentially harmful eruptions is challenged by the persistent mild ordinary activity, which often masks the precursory unrest signals related to heightened magma transport from depth. Gas (SO2 and CO2) fluxes at surface are controlled by rate of magma transport and degassing within the magma plumbing system, and thus constitute key parameters to infer deep magma budget and dynamics. Here, we use several year-long (2014-present) gas observations at Etna and Stromboli volcanoes, in Sicily, to provide new evidence for the utility of long-term instrumental gas monitoring in real-time detecting the early phase of unrest prior eruption, and for characterizing syn-eruptive dynamics. To this aim, we use information from a gas monitoring network of permanent ultraviolet (UV) cameras and automatic Multi-Gas instruments that, combined with geophysical observations, allow characterizing changes in degassing and eruptive dynamics at high temporal/spatial resolution. Our results show that the paroxysmal (lava fountaining) explosions that periodically interrupted persistent open-vent activity on Etna (during 2014-2020) were accompanied by systematic, repetitive SO2 emission patterns prior, during, and after eruptions. These allow us identifying the characteristic pre- syn- and post- eruptive degassing regimes, and to establish thresholds in the SO2 flux record that mark phases of unrest. On Stromboli, the much improved temporal/spatial resolution of UV cameras allows resolving the escalation of regular strombolian activity, and its concentration toward its North-east crater, that heralds onset of effusive eruptions. During effusive eruption, although magma level drops in the conduit and explosive summit activity ceases, UV camera observations can still detect explosive gas bursts deep in the conduit while no infrasonic activity is detected. Combining the UV camera-derived SO2 fluxes with CO2/SO2 ratio records measured by the Multi-Gas, the CO2 flux can be inferred. We find that such CO2 flux time-series can allow tracking degassing of deeply stored mafic magma months before Stromboli"s eruptions. We finally show that remotely sensed gas emission and thermal activity can be combined together to characterize the dynamics of shallow magmatic system prior to and during unrest, ultimately helping to define timing of magma re-charging events driving the eruptions.43 6 - PublicationOpen AccessFlank Instability Phenomena of the Sciara Del Fuoco at Stromboli Volcano, Italy: Recent Evidence From a Multidisciplinary Study(2005-12-05)
; ; ; ; ; ;Falsaperla, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Neri, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Pecora, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Spampinato, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia ;Langer, H.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Catania, Catania, Italia; ; ; ; The Sciara del Fuoco (SDF) at Stromboli volcano, located in the western side of the homonymous island, is a deep scar prone to phenomena of flank instability, such as rockfalls and flowing debris. By 30 December, 2002, landslides associated with tsunami waves affected both the sub aerial and submarine part of SDF two days after the onset of a new episode of lava emission. Recently, continuous monitoring as well as frequent structural field survey of SDF have provided an unprecedented opportunity for analyzing similar instability phenomena. Our study combines different data types in a complementary manner by merging geo-structural observations with visual images (taken by a video-cameras surveillance network and vertical air-photos) and seismic records. The goal of this research is to characterize this landslide-prone area for hazard mitigation purposes. The different data types are used to assess how and where SDF morphology changed in the time span from 2002 to 2004. The landslide phenomena of 30 December 2002 deeply eroded the SDF, creating a depression that in some points reached depths of several tens of meters. Afterwards, a reshape process began, through other minor erosive episodes and the deposition of lavas, which were erupted contemporaneously within a part of the collapsed/eroded zone, until the end of the eruption (21 July 2003). The effusion of lavas contributed to fill the depression, stabilizing a wide portion (more than 50 percent) of it and approaching a new gravitational equilibrium. Instead, in the zone of the landslides not reached by the lavas, erosive phenomena have continued to the present day, as evident from the progressive regression of the erosive rim, which has approached the crater zone. These phenomena yielded several rockfalls and flowing debris. Comparative video images and seismic records analysis provides an opportunity to detect the onset of these sliding episodes in time and space, and evaluate the mechanisms of motion. Additionally, this analysis allows us to document numerous explosion quakes and Strombolian explosions conducive to shaking instability. This evidence would result from external (quantity, quality, and position of the potential sliding material) as well as internal changes (location and energy of the seismo-volcanic source) in the volcano.122 135 - PublicationOpen AccessOn-line image analysis of explosive activity captured by surveillance cameras allows major eruptive events forecasting(2003-07-14)
; ; ; ; ;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 ;Pecora, E.; ; ; The use of stationary remote cameras for visual monitoring of the eruptive activity was implemented in the monitoring system of Etna and Stromboli volcanoes since 1993 and 1994 respectively. Camera records of eruptive activity became the major information source for describing eruptive phenomena occurred at Etna and Stromboli in the last years. However, the main goal of the continuous visual monitoring of active basaltic volcanoes is to analyze eruptive activity images in search of precursors of the paroxysmal events that suddenly interrupt the persistent mild strombolian activity. Stromboli represent the perfect test site for this investigation because its typical activity consists of intermittent mild explosions lasting a few seconds, which take place at different vents and at variable intervals. 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 the craters, endangering the numerous tourists that watch the spectacular activity from the volcano's summit located about two hundreds meters from the active vents. Using image analysis we identified any change of the explosive activity trend that preceded a particular eruptive event, like paroxysmal explosions, fire fountains and lava flows. The analysis include the counting of the explosions occurred at the different craters and the parameterization in classes of intensity for each explosion on the base of tephra dispersion and kinetics energy. From September 2001 an on-line image analyzer called VAMOS (Volcanic Activity MOnitoring System) operates detection and classification of explosive events in quasi real-time. The system has automatically recorded and analyzed the change in the energetic trend that preceded 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 and landslide forming eruption.106 112