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Inside the Crater: Everything You Need to Know about the Nisyros Volcano

  • December 1, 2018
  • Nisyros
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As you may have seen, Nissia Holidays is adding Nisyros to its portfolio for the 2019 season. We’re all really excited about the addition of this wonderful little island, and we hope you’re equally excited to explore another of Greece’s small, unspoilt islands.

You may also be wondering about the smoking volcano at the heart of Nisyros. Is it safe? How close can you get? We have all the answers…

Here’s everything you need to know about the Nisyros volcano.

The Grumbling Giant

According to the ancient Greeks, the earthquakes and smoking fumaroles of Nisyros were the actions of a grumbling giant. Mythology tells of a war between the Gods and the Titans, and a fight between Poseidon, God of the Sea, and the Titan, Polyvotis.

Poseidon catches Polyvotis near to Kos and, in anger, tears off a chunk of Kos with his trident, flinging it at the giant and trapping him beneath. Since then, Polyvotis has been huffing and puffing and struggling as he tries to break free.

The Scientific Version

Science tells a different story. Nisyros is the result of an underwater volcano that started to emerge from the sea about 150,000 years ago. Magmatic eruptions continued for a further 135,000 years to form the island we see today.

When Neolithic man arrived on Nisyros, c. 6,500 years ago, the violent eruptions of molten rock had ceased. Since then the only eruptions have been hydrothermal.

Hydrothermal eruptions occur when superheated water beneath the earth’s surface experiences a drop in pressure, causing a rapid transformation from liquid to steam. This results in an explosion of water, rock and mud debris. These eruptions are usually limited to the immediate area around the vent, and are the cause of the dramatic craters seen in Nisyros today.

The Craters

Located at the heart of Nisyros, the impressive caldera has a diameter of between three and four kilometres. Formed during the island’s explosive beginnings, there are magnificent views over this vast depression from the villages of Nikia and Emborio. Look out when flying to Rhodes, too – you get great views from the air!

Within the caldera there are a number of craters caused by hydrothermal eruptions, the largest of which have names such as Polyvotis, Alexandros, and Stefanos. One of the more recent craters, Stefanos is the most imposing and the most famous.

Stefanos is between 4,000 and 5,000 years old. Its diameter stretches between 260 and 330 metres, and it has a depth of around 27 metres. This elliptical crater is widely acknowledged as being one of the largest and best-preserved hydrothermal craters in the world.

For visitors to Nisyros, Stefanos is often referred to simply as ‘the volcano’, as it offers visitors a once-in-a-lifetime opportunity to walk within a potentially active volcano.

Visiting the Nisyros Volcano


Stefanos is one of the only active volcanic craters you can walk in anywhere in the world. Scramble down the rocky slope to find yourself in an otherworldly landscape. Holes of steaming, bubbling mud dot the crater floor fringed with neon-yellow, while a sulphuric whiff assails the senses and the heat seeps through the soles of your shoes. These holes are roped off, though you should still watch where you’re walking, but it’s an incredible experience and an opportunity to witness the unique geology of a volcano firsthand.

The last hydrothermal eruption was in 1888, though Polyvotis continues to grumble and groan from beneath the earth. Because it’s still a potentially active volcano, it’s monitored constantly for any unusual activity so it’s as safe as it can be, though as with any natural force there’s an element of risk.

To find out more about the volcano and other volcanoes in Greece, visit the wonderful Volcanological Museum in Nikia. It makes sense to visit here before descending into the crater.

Captivating Energy

The impact of the volcano goes far beyond the caldera and its craters. The crackling volcanic energy manifests throughout the island, with thermal baths just outside Mandraki and a natural sauna in a cave at the entrance to Emborio.

And then there are the colours. Black sand and black volcanic rock juxtapose whitewashed buildings and the deep blue of the Aegean. It’s dramatic and captivating, so it’s little wonder that the island is a magnet for artists with the Sterna Art Project, an annual residency programme for artists, based in Emborio.

Back in August 2016, 15 musicians gathered in the crater of Stefanos by the light of a full moon to improvise a performance inspired by their surroundings. By all accounts it was a mesmerising experience.

If you want to visit Nisyros to walk in a volcanic crater and experience this magnetic volcanic energy for yourself, contact Nissia Holidays or check out our accommodations options.

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