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The story behind Gunnuhver

Gunnuhver is an area of mud pools and steam vents located on the Reykjanes peninsula. It forms part of the Reykjanes UNESCO Global Geopark, giving it a protected status that recognises the importance of its landscapes. To understand Gunnuhver, we’ll learn how its geology is embellished with a tale from Icelandic folklore, making this a fascinating place for tourists to visit. Let’s uncover the story behind Gunnuhver.

What makes Gunnuhver special?

Iceland has many geothermal areas, some of which can be found on the Reykjanes peninsula.One of them, for instance, is Seltún, a colourful place with striking geology. Half an hour’s drive to the south west, Gunnuhver is another stand out. One of its unique selling points is that it’s home to the country’s largest mud pool.

Now, mud pools and mud volcanoes are not an uncommon sight around the world. There’s something quite mesmerising about the way hot mud plops and burps, luring people to far-flung destinations such as New Zealand, the USA and Azerbaijan.

But this huge mud pool, which measures an impressive 20 metres in diameter, is unusual, even by Icelandic standards. Normally, geothermal springs are of the freshwater kind. Here, instead, thanks to the area’s proximity to the ocean, the groundwater is actually formed solely of sea water. So Gunnuhver is particularly special on two counts.

Explaining geothermal areas like Gunnuhver

Heat beneath the earth’s surface, such as that caused by hot rocks or subterranean magma build-up, leads to geothermal activity. You’ll be alerted to its presence through distinctive landforms, such as mud pots and steam vents known as fumaroles. The amount and scale of this geothermal activity changes over time; hot springs and mud pots can be created or destroyed. For instance, the amount of activity in and around Gunnuhver increased in 2006.

But what causes such activity and why is there so much of it in Iceland? High temperature geothermal areas in Iceland are connected to its active volcanic systems. The presence of volcanoes in Iceland is down to its location where two tectonic plates meet. The North American and the Eurasian plates are pulling apart here, on the mid-Atlantic Ridge which runs diagonally across the country, including through Reykjanes.

Mud pots and hot springs are formed in very similar ways. The main difference is the volume of water that’s present – less at mud pots and more at hot springs. The geothermal activity means that the gases present, coupled with water that is sufficiently acidic to turn the ground into liquid clay, cause an accumulation of hot mud.

Incidentally, similar processes to this are also what leads to the formation of geysers. This is where superheated water is ejected and thrown high into the air as a jet of boiling water and steam. You’ll see this happen in the Haukadalur valley at Geysir – part of the famous Golden Circle route – though not at Gunnuhver.

These geothermally-related landforms will continue to be present as long as the source of heat remains. The geothermal water also contains high concentrations of dissolved chemicals. Some of the most common include sulphur, silica, and calcium carbonate, which is why if you visit areas like Gunnuhver, you’ll smell a whiff of rotten eggs in the air. It’s also common to see these deposits spattered on the ground; sulphur has a pale yellow colour, for instance.

Where are the best viewing places?

As with any natural landform, gaining a little height can be really useful in getting a better look. Here’s no exception. Close to Gunnuhver, it’s possible to walk up a wooden boardwalkand look down over the geothermal spring. You’ll get a clear sense of the geology up here, as the contrast between the verdant surroundings and bare rock is impossible to miss.

Alternatively, wander up Kísilhól, which is a nearby sinter mound whose name means ”silica hill”. Gaining this increased elevation is well worth the effort as you take in a landscape characterised by steaming indentations and rocky cones from which rivulets of water trickle downhill. One thing that will stand out is how this is an area that is changing before our very eyes – it’s hard not to be in awe of nature when she’s working so hard right in front of you.

Gunnuhver’s history

Iceland’s otherworldly landscapes have long been a source of fascination, both for locals and for foreigners. It’s believed that an Icelander called Eggert Ólafsson was the first person to record his thoughts and observations about geothermal areas like Gunnuhver in writing when he documented the place in the 18th century.

Eggert Ólafsson was born the son of a farmer but studied at the University of Copenhagen before returning to Iceland. He was a prolific author, but one of his most famous works is Reise Igiennem Island (Travels in Iceland) which records his findings following a lengthy trip he made across the country between 1752 and 1757.

Even to an Icelander, back then coming face to face with a landscape such as this must have been a mind-blowing thing. Think about how incredible we find it today, with the findings of scientific research to help us understand it and the resources of the internet to prepare us for a visit. A trip to Gunnuhver in the past must have been something else!

A folk tale explains the presence of a ghost

By far the most popular tale about Gunnuhver isn’t a history book, however, it is a folk story that has been passed down over the centuries by word of mouth. It concerns a former resident of Reykjanes called Gudrun Önundardottir, Gunna for short. At the turn of the 18th century, she lived near to where Keflavik Airport is today.

Gunna didn’t own her house, but rented it from a lawyer called Vilhjálmur Jónsson. One day, so the story goes, she didn’t have enough money to pay the rent. Another version of the story says she was a thief that had stolen from her neighbours. Regardless, her landlord wasn’t sympathetic to her plight and needed her to pay.

But Gunna couldn’t do so and protested as much. In place of cash, Jónsson took her cooking pot instead. It was probably the only thing of value that she had. Angry at losing such a precious object, Gunna flew into a rage and cursed him. That wasn’t all: she also placed a curse over the area itself, turning the land into a barren and infertile place. She was one angry woman!

Not long afterwards, Gunna died. During her funeral, the pallbearers who carried her coffin were puzzled that it felt surprisingly light. The fearful locals were even more confused when they claimed to have heard a voice saying: "No need deep to dig. No plans long to lie."Events took another strange turn when Vilhjálmur Jónsson was found dead.

Tongues started to wag – perhaps Gunna was a witch, they speculated. Surely these events couldn’t be a coincidence. In the absence of any credible explanation, people were seriously spooked. No one wanted to be the next victim. It was time to take drastic action and so they called for a pastor by the name of Eirikur. Perhaps the power of religion could lift the curse and they could all get on with their lives.

The folklore story explains Eirikur’s madcap idea. He was going to set a trap for Gunna’s ghost and to do so he had brought with him a ball of yarn. His plan was that he would unravel the string and use it to lure Gunna to a nearby hot spring. If you believe such stories, you won’t be surprised to hear that it worked.

You’ll often be told that the spirit fell into the boiling water where it met a steamy fate. An alternative version of events states that she couldn’t somehow let go of the rope, and instead paces endlessly around the rim of the mud pot. Regardless, unable to get out, the ghost of Gunna remains there today, giving the place its name: Gunnuhver.

Is it a true story? There might be some basis in fact for some of it. A woman named Gudrun Önundardottir is mentioned on a census return from the period. In the past, events that couldn’t be explained, even if they were coincidences, were blamed on witchcraft and such tales are commonplace. Our knowledge of geothermal and tectonic processes was very sketchy back then. No one really understood the science behind it and much of what was known was little more than descriptions made by interested observers.

Even now, some people have vivid imaginations. At Gunnuhver, they fancy that they can hear the sound of her falling, while others claim to have seen a shadowy figure running along its edge. The steam seems to hang here, no matter what the weather is doing. Perhaps it’s hiding Gunna’s ghost. Maybe it’s the work of the wind, but who wants to take that chance?

See it for yourself

As our understanding of scientific processes has increased, our desire to see geothermal landscapes such as Gunnuhver is stronger than ever. Its combination of geology, history and folklore make this one of Reykjanes’ most intriguing visitor destinations and one that never disappoints.

Is it safe to visit Gunnuhver? Yes. Nature is awesome and powerful – but should never be underestimated. The geothermal processes that are taking place at Gunnuhver need to be respected. Stick to the marked paths at all times. The water and mud here is incredibly hot and temperatures of more than 300°C (572°F) have been recorded. So while it’s safe to watchfrom a distance, it’s not a place to bathe or even stick your hand in.

But whatever you do, make sure you visit, as this is one natural landscape you won’t want to miss while you’re passing through the Reykjanes peninsula.