Publication Date:
2021-08-30
Description:
On 13 December 2020, Etna volcano entered a new eruptive phase, giving rise to a number of paroxysmal episodes involving increased Strombolian activity from the summit craters, lava fountains feeding several-km high eruptive columns and ash plumes, as well as lava flows. As of 2 August 2021, 57 such episodes have occurred in 2021, all of them from the New Southeast Crater (NSEC). Each paroxysmal episode lasted a few hours and was sometimes preceded (but more often followed) by lava flow output from the crater rim lasting a few hours. In this paper, we use remote sensing data from the ground and satellite, integrated with ground deformation data recorded by a high precision borehole strainmeter to characterize the 12 March 2021 eruptive episode, which was one of the most powerful (and best recorded) among that occurred since 13 December 2020. We describe the formation and growth of the lava fountains, and the way they feed the eruptive column and the ash plume, using data gathered from the INGV visible and thermal camera monitor- ing network, compared with satellite images. We show the growth of the lava flow field associated with the explosive phase obtained from a fixed thermal monitoring camera. We estimate the erupted volume of pyroclasts from the heights of the lava fountains measured by the cameras, and the erupted lava flow volume from the satellite-derived radiant heat flux. We compare all erupted volumes (pyro- clasts plus lava flows) with the total erupted volume inferred from the volcano deflation recorded by the borehole strainmeter, obtaining a total erupted volume of ~3 × 106 m3 of magma constrained by the strainmeter. This volume comprises ~1.6 × 106 m3 of pyroclasts erupted during the lava fountain and 2.4 × 106 m3 of lava flow, with ~30% of the erupted pyroclasts being remobilized as rootless lava to feed the lava flows. The episode lasted 130 min and resulted in an eruption rate of ~385 m3 s−1 and caused the formation of an ash plume rising from the margins of the lava fountain that rose up to 12.6 km a.s.l. in ~1 h. The maximum elevation of the ash plume was well constrained by an empirical formula that can be used for prompt hazard assessment.
Description:
Funding: This research was funded by the Project FIRST-ForecastIng eRuptive activity at Stromboli volcano: timing, eruptive style, size, intensity, and duration, INGV-Progetto Strategico Dipartimento Vulcani 2019, (Delibera n. 144/2020; Scientific Responsibility: S.C.). The research has moreover benefited from funding provided by the Italian Presidenza del Consiglio dei Ministri—Dipartimento della Protezione Civile (DPC), All. B2-Task 11 “Real-time quantification of Etna’s eruptive activity from fixed thermal cameras and satellite data”. (Scientific Responsibility: G.G.) and Task 9 “Ottimiz- zazione dell’acquisizione dei segnali ad alta precisione degli strainmeter installati in pozzo sull’Etna” (Scientific Responsibility: A.B.). A.B. also benefited from the EC 298H2020-FET OPEN project grant agreement n. 863220 “SiC optical nano-strain-meters for pico-detection in Geosciences” (SiC nano for picoGeo). This paper does not necessarily represent DPC’s official opinions and policies.
Description:
Published
Description:
3052
Description:
6V. Pericolosità vulcanica e contributi alla stima del rischio
Description:
JCR Journal
Keywords:
Etna volcano
;
paroxysmal explosive and effusive episodes
;
volcanic hazard
;
volcano monitoring
;
remote sensing
;
Etna volcano, paroxysmal explosions, volcanic hazard
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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