Basaltic volcanic systems are particularly acknowledged for producing predominantly effusive activity, chiefly due to the physical and chemical properties of magmas. However, even basaltic volcanoes can produce explosive activity, which is often characterized by the production of energetic lava fountains. In the recent decades, Mt. Etna has given rise to several sequences of lava fountains, also known locally as paroxysmal eruptions. The last sequence began on December 13, 2020, and ended on February 21, 2022, producing sixty-two paroxysmal episodes from the South East Crater (SEC). Some lava fountains, among those occurred during the 2020-2022 paroxysmal sequence, have reached considerable, although variable, heights and intensities, occurring under largely different wind speeds and producing sometimes eruptive columns rising up to 15 km above sea level (a.s.l.). During such kind of events, several ballistics fell around the summit craters, sometimes reaching touristic areas. The rather frequent activity poses primary questions on how the impact associated with the fallout of these particles can be estimated. In this work, we present field data collected soon after the lava fountain of February 21, 2022. This event produced high lava fountains (>1000 m above the crater edge) and a volcanic plume about 10 km a.s.l. which was directed toward southeast. Several large ballistics fell in the area of the Barbagallo Craters (just southeast of the summit area at around 2900 m a.s.l.), which is one of the most popular touristic areas on Mt. Etna. Hence, we collected several samples and performed laboratory analyses in order to retrieve their size, shape and density. Values obtained, together with the quantitative analysis of lava fountain, have been compared with results acquired through a calculator of ballistic trajectories ejected during explosive eruptions, which is named “Eject! software” (Mastin, 2001) and is free-available to the volcanological community. We have therefore estimated the main eruption conditions occurred during this lava fountain event and compared them with other data obtained by other remote sensors, including weather data and the relative height of the incandescent jet region of the lava fountain (Mereu, L., et al., 2020) during the paroxysmal phase of this eruptive event. A similar approach has been hence applied to other lava fountains of the 2020-22 sequence, which were characterized by different eruptive and meteorological conditions with respect to that of February 21, 2022 and for which the fallout of large clasts was reported. This work is a first step to identify a real-time and free available system capable of assessing the possible impact by fallout during the Mt. Etna lava fountains, in order to mitigate the risk associated with the fallout of large ballistics, especially close to areas densely affected by tourists and hikers.
Trajectories of ballistics and assessment of the hazard in the summit area of Mt. Etna (Italy) related to the 2020-22 sequence of lava fountains
Costa, Giorgio;Viccaro, Marco
2023-01-01
Abstract
Basaltic volcanic systems are particularly acknowledged for producing predominantly effusive activity, chiefly due to the physical and chemical properties of magmas. However, even basaltic volcanoes can produce explosive activity, which is often characterized by the production of energetic lava fountains. In the recent decades, Mt. Etna has given rise to several sequences of lava fountains, also known locally as paroxysmal eruptions. The last sequence began on December 13, 2020, and ended on February 21, 2022, producing sixty-two paroxysmal episodes from the South East Crater (SEC). Some lava fountains, among those occurred during the 2020-2022 paroxysmal sequence, have reached considerable, although variable, heights and intensities, occurring under largely different wind speeds and producing sometimes eruptive columns rising up to 15 km above sea level (a.s.l.). During such kind of events, several ballistics fell around the summit craters, sometimes reaching touristic areas. The rather frequent activity poses primary questions on how the impact associated with the fallout of these particles can be estimated. In this work, we present field data collected soon after the lava fountain of February 21, 2022. This event produced high lava fountains (>1000 m above the crater edge) and a volcanic plume about 10 km a.s.l. which was directed toward southeast. Several large ballistics fell in the area of the Barbagallo Craters (just southeast of the summit area at around 2900 m a.s.l.), which is one of the most popular touristic areas on Mt. Etna. Hence, we collected several samples and performed laboratory analyses in order to retrieve their size, shape and density. Values obtained, together with the quantitative analysis of lava fountain, have been compared with results acquired through a calculator of ballistic trajectories ejected during explosive eruptions, which is named “Eject! software” (Mastin, 2001) and is free-available to the volcanological community. We have therefore estimated the main eruption conditions occurred during this lava fountain event and compared them with other data obtained by other remote sensors, including weather data and the relative height of the incandescent jet region of the lava fountain (Mereu, L., et al., 2020) during the paroxysmal phase of this eruptive event. A similar approach has been hence applied to other lava fountains of the 2020-22 sequence, which were characterized by different eruptive and meteorological conditions with respect to that of February 21, 2022 and for which the fallout of large clasts was reported. This work is a first step to identify a real-time and free available system capable of assessing the possible impact by fallout during the Mt. Etna lava fountains, in order to mitigate the risk associated with the fallout of large ballistics, especially close to areas densely affected by tourists and hikers.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
