What made Mount Etna's latest eruption so rare

Hamilton Spectator

2 days ago

MILAN (AP) — Mount Etna, the volcano that towers over eastern Sicily, has again captivated the world with a spectacular show, spewing smoke and high into the sky.
But the defining event of Monday's eruption was the more rare pyroclastic flow from the southwestern crater not visible from a distance.
The volcano is Europe's most active, and the continent's largest. Etna attracts hikers and backpackers to its slopes while less adventurous tourists can take it in from a distance, most stunningly from the Ionian Sea.
Etna's latest eruption caused neither injuries nor evacuations, but sent a group of tourists on its flanks running, as captured by video posted on social media with smoke towering in the background.
Authorities emphasized there was no danger to the population, and the pyroclastic flow — a fast-moving mixture of rock fragments, gas and ash — was limited to about 2 kilometers (more than a mile) and didn't go beyond the Valle del Leone, or Lion Valley, which forms a natural containment area.
Etna has been active recently, and this was the 14th episode since mid-March. The most recent pyroclastic flows with significant reach were recorded on Feb. 10, 2022, Oct. 23, 2021, Dec. 13, 2020 and Feb. 11, 2014, Marco Viccaro, president of Italy's national volcanology association, said Tuesday.
What's happening now?
After a 19-day lull, Etna began to erupt with lively explosive bursts of gas and ash followed by a mild lava flow on the eastern slope followed by a smaller flow to the south.
At around 10 a.m. on Monday, Etna exploded with its first major, violent eruption of the year: lava fountains and a column of ash and gas rose several kilometers, or miles, in the air. The event climaxed around 11:23 a.m. when the pyroclastic flow, triggered when magma mixed with snow, traveled 2 kilometers (more than a mile) to the Valle del Leone within a minute.
By late afternoon, scientists said the event had subsided.
Imposing figure
Etna towers around 3,350 meters (around 11,050 feet) above sea level and is 35 kilometers (22 miles) in diameter, although the volcanic activity has changed the mountain's height over time.
Occasionally, the airport at Catania, eastern Sicily's largest city, has to close down for hours or days, when ash in the air makes flying in the area dangerous. An aviation warning was put in place during the latest event, but the airport wasn't closed.
With Etna's lava flows largely contained to its uninhabited slopes, life goes in towns and villages elsewhere on the mountain. Among the benefits of the volcano: fertile farmland and tourism.
Deadly past
Inspiring ancient Greek legends, Etna has had scores of known eruptions in its history. An eruption in 396 B.C., has been credited with keeping the army of Carthage at bay.
In 1669, in what has been considered the volcano's worst known eruption, lava buried a swath of Catania, about 23 kilometers (15 miles) away and devastated dozens of villages. An eruption in 1928 cut off a rail route circling the mountain's base.