Mount Etna

Mount Etna is the tallest active volcano in Europe, rising approximately 3,357 metres above the eastern coast of Sicily, Italy. It is one of the most active volcanoes in the world: Etna has erupted thousands of times throughout history and is currently erupting on most days of the year. Yet despite the constant activity, approximately 900,000 people live in the area around it, growing famous wines, olives and pistachios in the unusually fertile volcanic soil. Etna has been a UNESCO World Heritage Site since 2013 and is one of the most-studied volcanoes on Earth.

• Height3,357 mTallest active volcano in Europe
• TypeStratovolcano with active cone
• LocationSicily, ItalyEastern coast
• AgeApproximately 500,000 years
• People nearbyApproximately 900,000Including the city of Catania
• Frequency of eruptionsNearly constantSmall eruptions almost every day

Why Etna is always active

Etna sits in an unusual geological setting: a complex collision zone between the African and Eurasian plates, with a deep fault system that constantly feeds magma to the surface. Unlike many volcanoes that build up pressure for centuries between eruptions, Etna releases its energy in many small frequent eruptions rather than rare catastrophic ones. This makes it relatively safe to live near, although it is far from harmless.

Etna throughout history

Etna has been an important presence in human history for thousands of years.

• Ancient Greeks believed Etna was the forge of Hephaestus, the god of fire and metalwork.
• Ancient Romans thought it housed the workshop of Vulcan (their version of Hephaestus), giving us the word "volcano".
• 122 BC: A large eruption darkened the sky over Sicily and damaged buildings in nearby Catania.
• 1669: A major eruption sent a lava flow that destroyed parts of Catania, killing approximately 20,000 people and reaching the sea.
• 1928: A lava flow destroyed the village of Mascali in just a few days.
• 1992: A major eruption was diverted by carefully designed earth barriers and explosive charges (one of the few successful attempts to redirect a lava flow).
• 2002 to 2003: Multiple eruptions caused ash falls as far away as Libya.
• 2021: A series of paroxysmal eruptions raised the height of the volcano by 30 metres in just a few months.

Living with the volcano

People have lived on and around Mount Etna for over 4,000 years, despite the obvious risks. The reason is simple: the soil is extraordinarily fertile. Volcanic ash and weathered lava produce some of the best agricultural soils in the world, rich in minerals that plants need. Famous local products include:

• Etna wines: Sicilian wines from the volcano's lower slopes have become hugely popular in recent decades. The mineral-rich soil and high altitude produce distinctive wines.
• Olive oil: Etna's olive groves are some of the most productive in Italy.
• Pistachios: the Bronte region on Etna's western slope is famous for producing some of the world's finest pistachios.
• Honey: Etna's wild flowers feed bees that produce distinctive local honey.

Fact Mount Etna is one of the few volcanoes in the world that has been deliberately diverted. In 1992, when a major lava flow threatened the town of Zafferana Etnea, Italian authorities used controlled explosions to break through the side of the lava channel and redirect the flow into an empty valley. The operation worked, saving the town. It remains one of the few successful attempts to control a volcanic eruption.

The four summit craters

Etna has four summit craters that have all been active in recent years.

• Voragine (formed 1945)
• Bocca Nuova ("new mouth", formed 1968)
• North-east Crater (formed 1911): the highest point of the volcano.
• South-east Crater (formed 1971): currently the most active, producing the spectacular eruptions of recent years.

Plus many smaller side vents that open up during particular eruptions and then go quiet for years.

Did you know? Tourists can take cable cars and jeep tours partway up Etna, even during periods of active eruption. The volcano is so frequently active that the local authorities have well-established procedures for moving visitors out of danger when necessary. Skiing is also popular on Etna in winter: it is the only place in the world where you can ski on the slopes of an active volcano with a beach a short drive below.

Deeper dive: why volcanic soil is so fertile

One of the most surprising things about living on a volcano is how productive the land can be. Some of the world's richest farmland sits in the shadow of active volcanoes: the rice paddies of Java, the coffee plantations of Costa Rica, the wine vineyards of Etna and Vesuvius, the vegetable gardens of Hawaii. Why?

The answer is in the chemistry of volcanic rocks. Volcanic ash and weathered lava contain a wide range of minerals that plants need: phosphorus, potassium, magnesium, calcium, iron, sulphur and many trace elements. Most ordinary soils get these nutrients only slowly from weathering bedrock, and farming gradually depletes them. Volcanic eruptions, by contrast, dump huge fresh quantities of minerals onto the surface in one go.

Volcanic soils also have several other useful properties.

• They drain well because volcanic particles are porous, with good air spaces for plant roots.
• They hold water better than sandy soils.
• They warm up quickly in spring because dark volcanic ash absorbs sunlight.
• They renew themselves with each new eruption, while non-volcanic farmland slowly loses fertility over centuries.

This is one of the reasons human populations have stuck so close to volcanoes throughout history despite the dangers. The land near a volcano supports more people per square kilometre than equivalent non-volcanic land, generation after generation. The price is the occasional catastrophic eruption, but most people throughout history have decided the trade-off is worth it. Modern populations of Naples (around Vesuvius), Jakarta (between several Indonesian volcanoes) and Tokyo (within sight of Fuji) continue the long tradition.

For more, see types of volcano and Mount Vesuvius.