Year 2021 was one of the “busiest years” on Mount Etna in terms of eruptions. A crisis that began in 2020 led Sicily’s great volcano to erupt at an impressive rate for the next 20 months. So, what could be so “mysterious” in a paroxysm of 2021, that is in just one of the many spectacular eruptions that characterized that entire year? We find out together with the INGV-Vulcani blog which was the first to draw attention to this event. An event that could certainly have “escaped” normal people’s eye, but which instead became important in the study of the volcano.
March “on fire”
March 2021 was a month “on fire”, literally. In that period, Etna erupted four or five times in a row, with very short pauses between one event and another. Between March 10th and March 31st, marvelous fire fountains, eruptive columns, lava flows were recorded, with the volcano completely in turmoil and offering almost no pauses. People had definitely “got used” to the show, and also to the annoyances associated with it. Almost no one noticed anything different in the eruption that characterized that end of the month. Yet this particular paroxysm is defined as “anomalous” or “mysterious”.
The paroxysm of March 31-April 1
This paroxysmal event began on March 31st around 11 am and ended the following day late at night, almost at dawn on April 2nd.
What makes it anomalous and mysterious, compared to the many paroxysms that preceded it (and that will follow it), was the long duration, the set of phenomena that occurred and the copious quantity of lava emitted. Long duration because, as a rule, each paroxysm lasted a few hours and then ended. This instead went on for 48 hours without any break. In this period of time it produced a series of phenomena (cracks in the ground, effusive vents, lava fountains) which usually manifested themselves separately. Finally, there was a huge amount of lava emitted from an “ephemeral vent” which normally should emit little or nothing.
Dynamics of the event
The signs of yet another paroxysm were already evident at dawn on March 31, 2021. The activity intensified around 11 am, particularly from the South Eastern peak and from a vent that opened on the southern side of the crater. The small fracture, however, immediately began to emit long rivers of lava which by the evening of the 31st had already reached the edge of the Valle del Bove.
At the same time, new fissures opened on the eastern part of the large crater, also adding to the lava emission from the first vent. During the night, the classic lava fountain typical of these phenomena also joined the “choir”. On the morning of April 1, activity seemed to swarm but settled into degassing and Strombolian explosions. Quoting INGV-Vulcani: < The lava emitted from the vents at the southern base of the South-East Crater has expanded like a fan, feeding the flow already active since the previous morning, towards the Valle del Bove. A second branch, oriented towards south-southeast, ran along the western edge of the Valle del Bove towards the panoramic point known as “Belvedere”; a third flow, directed towards the south-southwest, poured into the saddle between the cones of Monte Barbagallo (2002-2003 eruption) and Monte Frumento Supino >. Everything ended on the night between 1 and 2 April.
After this paroxysm the map of the summit of Etna definitively changed. (THE PHOTOS ARE BY GRAZIA MUSUMECI)