The new, sudden eruption of Mount Etna, which began at dawn on July 30, officially ended on August 1st. It was an eruption that had started like many others… increased tremors, paroxysm with lava fountains… but which had an “anomalous” ending, though not entirely new: a fracture in Valle del Leone. Given the low altitude (around 2,700 meters) where the new fracture opened, we can also consider this a lateral eruption, even though there was never any danger to the remote urban centers. But why, over the last two years, has Etna repeatedly opened lateral vents in this fragile area, north of the summit crater system, known as Valle del Leone? With the help of two volcanologists from Catania, we try to understand.

Valley of the Lion: a high-resonant name for a fragile area

We’ve written about this valley before, which is actually a collapsed caldera that reminds us that Mount Etna was once very different and much higher. Does it have to do with real lions? No, there were no lions on Etna, so this desert of black rock that opens to the north, between the summit craters, Monte Nero delle Concazze and Pizzi Deneri, owes its high-resonant and proud name only to a corruption of the Sicilian dialect (the word “vadduni,” meaning “great valley,” was Italianized to “vallone,” and from there to “val leone”, the valley of the lion).

And in fact, there’s nothing strong or proud about this valley. On the contrary, it’s one of the most fragile and precarious areas of the volcano’s structure. Here, the crust seems to suffer greatly from the internal pushing of the magma and especially from fault movements, like those that for centuries have tended to split Etna in two, between east and west. As Dr. Boris Behncke of the INGV Institute in Catania explains: “These fractures open at the foot of the craters along lines of structural weakness typical of Etna—as demonstrated by the fracturing of past years, from 1928 to 1989. That area is possibly still affected by the consequences of the 2018 earthquake, the most recent, which, however, accentuated the sliding of the eastern slope of the volcano.”

If you want to visit the Valle del Leone and the many fractures and lava flows that have affected it, you can find useful information in this article on our blog: https://www.go-etna.com/blog/the-valley-of-the-lion/ .

The latest eruption in the Valle del Leone

At dawn on July 30, Etna began to show signs of agitation with degassing and lava fountains from the Voragine crater. The same crater produced (source: INGV) “a lava flow that poured into the northeast crater and an ash emission that spread in a southwesterly direction. Finally, ash fallout was reported in the Monte Denza area.”

In addition to this initial panorama, on the evening of July 30th, an effusive fracture occurred in the Valle del Leone area. The INGV also states: “in the upper Valle del Leone sector, at an altitude of approximately 2,700 m above sea level, effusive activity continued throughout the night and reached an estimated altitude of around 1,700-1,750 m above sea level, upstream of Rocca Capra, in the Valle del Bove.” The flow continued to flow weakly until the morning of August 1st, when it was completely stopped. Therefore, at this time, the eruption can be declared over, barring any “aftershocks” and surprises typical of the eruptive style of this large Sicilian volcano.

The disappointment of tourists who could only witness the event from afar, save for a lucky few who were already at altitude when the first eruption struck (see photos by Go Etna staff), was compounded by the constant wonder of enthusiasts and the sigh of relief of locals who, for a moment, feared a different and more extensive development of the lava flow.

So what’s happening on Etna?

Dr. Marco Neri explains, reminding us that “Etna doesn’t open fractures randomly. There are at least three main sectors where magma intrusions occur most frequently, and these zones are called Volcanic Rifts. Specifically, we have a Northeast Rift, a West Rift, and the Southern Rift. The vast majority of Etna’s lateral eruptions follow one of these structural trends, and sometimes even two simultaneously! The reason for explaining these rifts would be a long discussion. However, it must be kept in mind that the deformation of the eastern flank of the apparatus, which causes this sector to “slide” (an improper but figuratively effective term) toward the Ionian Sea, produces some separation zones between the unstable and stable blocks that show on the surface as tectonic faults (such as the Fleri fault, see the 2018 earthquake), and these zones, rising upward, coincide with part of the volcanic rifts.”

So, when fractures open in the Valle del Leone, it’s precisely because in this area the Northeast Rift is at its peak, it is an alternative escape route for magma when it wants—or must—escape from the volcano’s central conduits. So these fractures in these areas aren’t “random” occurrences, but rather “recurrences”, because where the ground is already fragile due to the presence of previous fractures, magma finds its way more easily through the rocks, toward the surface.

Let’s prepare for the spectacle with great caution

As always, we don’t know if it’s all over or if Etna is just taking a break before resuming its show.

Etna’s eruptive spectacle during the summer is one of the most fascinating and evocative natural events in Europe. The continent’s highest active volcano knows how to attract tourists, and it does so with enviable finesse and punctuality. This season, the contrast between the dark blue sky and the brilliant red lava creates a breathtaking scene, attracting photographers, hikers, and volcanology enthusiasts from around the world. Despite the event’s allure, it is essential to respect the authorities’ instructions and maintain a safe distance from areas affected by eruptive activity. Etna’s eruptions have shaped the landscape, making the soil particularly fertile and favoring the cultivation of vineyards, citrus groves, and fruit orchards. For the residents of the surrounding areas, the volcano is both a precious resource and a presence to be carefully monitored because, as mentioned, that same fertile soil is sometimes very fragile and ready to break, giving rise to lateral eruptions… spectacular, yes, but not always safe.

Witnessing a summer eruption of Etna is an unforgettable experience, where the power of the Earth manifests itself in all its magnificence. It is a spectacle that inspires wonder, respect, and awareness of the incredible dynamism of our planet.