Surtsey: The Island That Rose From the Sea in 1963 and Is Still Off-Limits

At a quarter past seven on the morning of November 14, 1963, the cook on the Icelandic fishing boat Ísleifur II saw a column of dark smoke rising from the sea to the southwest. The captain guessed that another boat was on fire and turned to help. There was no boat. The crew found black clouds of ash and steam blasting straight up out of the water off Iceland’s Westman Islands. A volcano had reached the surface of the North Atlantic.

Within days there was an island. Within four years it covered more than two and a half square kilometers and rose 174 meters above the waves. Iceland named it Surtsey, after Surtr, the fire giant of Norse myth, and then did something unusual with it. Before the eruption had even finished, the government declared the new island a nature reserve and closed it to almost everyone. More than six decades later, that is still the rule. Only a handful of scientists may set foot on Surtsey, and they have to arrive clean.

The result is one of the longest experiments in natural history: a piece of brand-new land, born sterile, left alone, and watched as seeds, insects, birds and seals arrived by themselves. What the researchers have learned is not quite what anyone predicted in 1963.

A fire under the sea

Surtsey sits about 32 kilometers off the south coast of Iceland, on the Vestmannaeyjar volcanic system, a field of small submarine vents that has been building islands off this coast for thousands of years. Iceland straddles the Mid-Atlantic Ridge, where the North American and Eurasian plates pull apart, and the Westman Islands sit on the southern end of one of its active volcanic zones.

The eruption started 130 meters below the sea surface, probably a few days before anyone saw it. A seismograph at Kirkjubæjarklaustur, on the mainland, picked up small tremors between November 6 and 8, and people in the coastal village of Vík noticed a smell of hydrogen sulfide in the air on November 13. That same day a fishing boat working the area measured the sea at about 2.4 degrees Celsius warmer than normal. Nobody connected the clues until the cook on the Ísleifur II looked up.

By late that morning the ash column was climbing high into the sky. The eruption came from three vents lined up along a fissure running northeast to southwest, and by afternoon their plumes had merged into one. After a few days the pile of black cinders had broken the surface and grown into a ridge more than 500 meters long and 45 meters high. By November 24 it measured about 900 by 650 meters.

What made the eruption so violent was water. When hot basalt magma meets cold seawater, the water flashes to steam and shatters the molten rock into fine ash and cinders. Each pulse threw dark jets of debris skyward, and the main steam and ash cloud climbed as high as 10 kilometers. Volcanic bombs were hurled up to a kilometer from the vent. The Icelandic geologist Sigurður Þórarinsson, who studied the island closely from its first days, described this style of shallow-water eruption so thoroughly that volcanologists now call it a Surtseyan eruption, after the island itself.

Surtsey quickly became a celebrity. Scientists from Iceland and abroad came to study it, and the press arrived too. On December 6, 1963, three journalists from the French magazine Paris Match landed on the hot black beach. They stayed for about 15 minutes before violent explosions persuaded them to leave, and they joked afterward that they had claimed the island for France. Iceland did not take the claim seriously.

How a pile of ash became an island

Islands made of loose volcanic cinders do not usually last. The waves of the North Atlantic are among the most powerful on Earth, and they can scour away a heap of loose ash in months. That is exactly what happened to the volcano’s younger siblings. On December 28, 1963, a second vent opened under the sea to the northeast. It built a ridge about 100 meters high on the sea floor, which was named Surtla, but it never reached the surface. In May 1965 another vent formed a small island just off Surtsey’s north shore, called Syrtlingur, or Little Surtsey. It was washed away in early June, reappeared on June 14, and kept erupting until early October. Three weeks later, on October 24, 1965, the waves had taken it.

A third island rose less than a kilometer southwest of Surtsey in December 1965 and was named Jólnir, after jól, the Icelandic word for Christmas. Over the next eight months it appeared and disappeared several times as volcanic growth and wave erosion took turns winning, and at its peak it stood about 70 meters high. Its eruption ended on August 8, 1966, and by October that year Jólnir was gone.

Surtsey survived because of a change in the way it erupted. By early 1964 the island had grown big enough to keep seawater away from the main vent, and the explosive blasts of ash gave way to fountains and rivers of lava. Starting in April 1964, lava flows spread over much of the southern half of the island and hardened into a thick cap of solid basalt. That armor is the reason Surtsey is still on the map.

The last phase began on August 19, 1966, with fresh lava pouring from new vents. The activity slowly weakened, and on June 5, 1967, three and a half years after the cook spotted the smoke, the eruption ended. In total the volcano had produced about a cubic kilometer of lava and tephra. At its largest, the island covered about 2.7 square kilometers.

An island closed while it was still being born

Biologists understood from the start what an opportunity Surtsey offered. Most studies of how life colonizes new ground begin on land that has already been disturbed by people, or that sits next to ground full of seeds and soil. Surtsey was surrounded by open ocean, sterilized by heat, and completely new. If people could be kept off it, it would show how plants and animals find their own way to an empty island.

So in 1965, while lava was still flowing, Iceland declared Surtsey a protected nature reserve. Research there is coordinated by the Surtsey Research Society, and landing requires a permit, granted only for scientific work. Going ashore and diving in the protected waters around the island are forbidden to everyone else. The only way most people can see Surtsey up close is from a small plane or a boat passing at a distance. In 2008, UNESCO added Surtsey to the World Heritage List, describing it as a pristine natural laboratory free from human interference since its birth.

The rules for scientists are strict. Visitors check their clothes, boots and bags for seeds before landing. There is a small prefabricated hut with a few bunks and solar panels, a weather station and a webcam installed in 2009, and the foundation of an old lighthouse. That is almost the entire human footprint on the island.

Almost. Not every intrusion was planned. According to the island’s history, some boys from Heimaey once rowed over and planted potatoes, which were dug up when they were discovered. Another time, a tomato plant sprouted on Surtsey from human waste left by a visitor, and it was promptly destroyed. A new island turns out to be a very good place to see exactly how careless people can be.

Surtsey shares that strange status with a short list of other places, from the cave paintings of Lascaux, which France closed to the public in the very same year the island was born, to the Pacific islands you really cannot visit. What sets Surtsey apart is that it was protected before it had even finished forming, so people never had the chance to change it.

The first arrivals

The colonists came almost at once. Bacteria, molds and insects were blown or carried in within the first months. In the spring of 1965, during the eruption, scientists found the first vascular plant growing on the north shore: sea rocket, a seashore plant whose seeds can travel by sea. Mosses turned up in 1967, and the first lichens were found on the lava in 1970.

For the first two decades, the plant life grew slowly. Seeds arrived by sea, on the wind and in the guts and feathers of birds, but the island was a harsh place to germinate. Sand, gravel and lava hold almost no water and no nitrogen. Sea sandwort, a tough, low-growing beach plant, did best. It spread over the sandy parts of the island and is still one of its most common plants.

Seabirds were the first to make Surtsey a home. Fulmars and black guillemots were nesting on the cliffs by about 1970. They used the island as a place to raise chicks, not as a feeding ground, so their effect on the bare land was small. Grey seals began hauling out on the beaches and started breeding there in 1983.

The gulls that changed everything

The turning point came in the mid-1980s. Around 1985, gulls began to nest on the southern part of the island in large numbers: lesser black-backed gulls, herring gulls and great black-backed gulls. Unlike the cliff-nesting seabirds, gulls collect food over a wide area and bring it back to their nests, and they drop droppings, food scraps and seeds wherever they settle.

The effect was dramatic. Within the gull colony, the bare sand and lava turned green. Nitrogen from the birds fertilized the ground, grasses and herbs took hold, and soil started to form. Insects, spiders and other invertebrates followed the plants. A study of a single grass tussock in 1974 had already found 663 invertebrates living in it; by the 1990s the colony area held a much richer community. Earthworms were found in 1993 and slugs in 1998. The first willow bush was recorded in 1998.

Surtsey has spent six decades answering it, one seed at a time.

Land birds came after the plants. Snow buntings became the first land birds to breed on Surtsey in 1996. Puffins, the mascot of the Westman Islands, were found nesting in 2004. Greylag geese started breeding in 2002 and ravens a few years later. By 2004, scientists had recorded 89 bird species on the island and 335 species of invertebrates.

The plant count kept rising for decades. By 2022, botanists had recorded 78 species of vascular plants on Surtsey since the eruption. Not all of them stayed. About 63 were still living there in 2022, and only around 40 of those had established lasting populations. The rest arrived, grew for a season or a few years, and died out. Recent surveys have found the number of species at a plateau, and in some years falling, as the gull colony and the soil it built settle into a steadier state.

That boom-and-bust pattern is one of the island’s main lessons. Colonizing new ground is less like a steady march than a series of trials, most of which fail. Island biologists had predicted something like it in theory. Surtsey gave them a real island where they could count the arrivals and departures year after year.

The island is shrinking, and turning to stone

Surtsey is losing ground. The waves have taken away a large slice of the southeast side, and the island has lost about half of its original area. It covered roughly 1.3 square kilometers in 2012, and its highest point had dropped to about 155 meters. The island loses about one hectare a year, and its surface is slowly sinking as the volcanic pile settles.

It will not disappear any time soon, though. Most of what has washed away was loose tephra. What is left is mainly protected by the hard lava cap, and something remarkable has been happening inside the island too. Hot water circulating through the loose ash has turned much of it into a hard rock called palagonite tuff, which resists erosion far better. On Surtsey this process, which normally takes much longer, happened within a few decades because the inside of the island stayed hot. The neighboring islands of the Westman group, which formed the same way thousands of years ago, offer a preview of the future: small, steep-sided tuff islands that waves have whittled down but not removed. Estimates of Surtsey’s remaining life run to centuries.

In 2017, an international team drilled into the island to watch that process from inside. The project, called SUSTAIN and supported by the International Continental Scientific Drilling Program, drilled three holes in August and September 2017, one of them angled at 35 degrees to a length of 354 meters, beside a hole drilled in 1979. Temperatures in the boreholes reached more than 120 degrees Celsius. It was a much shallower cousin of Project Mohole, the 1960s attempt to drill through the ocean floor to the Earth’s mantle, but aimed at a question that turned out to have a surprising link to ancient Rome.

Cores from Surtsey, starting with the one drilled in 1979, showed that the hot seawater inside the island had grown a mineral called aluminous tobermorite, the same rare crystal that helps bind Roman marine concrete. In a 2017 study of ancient Roman harbor structures, the geologist Marie Jackson and her colleagues found tobermorite in the Roman mortar with compositions nearly identical to the crystals in Surtsey’s young tuff, and argued that both formed through similar low-temperature reactions between volcanic ash and seawater. Roman builders, who mixed volcanic ash with lime and set it in the sea, had in effect harnessed a process that Surtsey was carrying out on its own. Researchers hope that understanding it better could help make more durable, lower-carbon concrete.

Ten years later, next door

Surtsey was not the end of the story for the Westman Islands. Ten years later, on January 23, 1973, a fissure opened on the edge of the town on Heimaey, the largest and only inhabited island in the group, a short boat ride to the northeast. Almost all of the roughly 5,300 residents were evacuated by boat that night. Over the following months a new volcano, Eldfell, destroyed or buried several hundred buildings and threatened to close the harbor that was the town’s economic lifeline. Crews pumped seawater onto the advancing lava for months, and the harbor survived. In Iceland, the lessons from Surtsey and Eldfell are part of the same story of living in a restless volcanic country, the one that also produced the Laki eruption of 1783.

Watching from a distance

Most people will only ever see Surtsey from the deck of a boat out of Heimaey, from a sightseeing flight, or on the webcam. That is the point. The island is valuable because it has been left alone, and every boot on it is a small risk to the experiment. Among the closed islands of the world, a place like Ball’s Pyramid, the sea stack where the tree lobster survived, is protected because of what it has kept; Surtsey is protected because of what it might still become.

After more than 60 years, the island that rose out of the sea in front of a fishing crew has soil, grass, nesting puffins, seal pups on its beaches and earthworms in its ground. Its scientists still land a few times a year, count what has arrived and what has gone, and leave as carefully as they came. Somewhere in their notebooks is the answer to a question as old as the first oceanic islands: how does an empty piece of rock become a living place? Surtsey has spent six decades answering it, one seed at a time.

Further reading