One of Earth’s loneliest volcanoes holds an extraordinary secret
Published February 27, 2023
11 min read
When Emma Nicholson peeked into the crater of a remote volcano in the southern Atlantic Ocean, the British volcanologist gazed on a scene no human has seen before. The crater’s walls dropped steeply to the floor below, where, hidden from view, lies a lake of molten lava—one of nature’s rarest phenomena.
Nicholson stood near the crater’s rim atop Mount Michael, an active stratovolcano about a thousand miles north of Antarctica, as a drone transmitted images of a lava pool far below to the hand-held screen in front of her.
“Suddenly, we could see this small lava lake right deep down inside the crater,” Nicholson recalls. “It was certainly not maybe the lava lake that you’d naturally conjure to mind … but it was unmistakably lava close to the surface, feeding the gas plume we were measuring.”
Nicholson, who co-led a National Geographic Society expedition last November that made the first ascent of Mount Michael to confirm the presence of molten lava on the crater floor. That, together with a bevy of field experiments will help advance the growing body of research into volcanic behavior. Scientists are still trying to understand how to read volcano signals and patterns. Which of them could be precursors to an eruption? Can signals of one volcano be applied to other volcanoes? Lava lakes, especially their activity inside volcanic craters, may hold some of those answers.
Unlocking clues to volcanic behavior
Lava lakes are among the planet’s most unusual geological features. Though there are about 1,500 active volcanoes on Earth, Mount Michael is only the eighth lava lake to be discovered. Some are bubbling cauldrons of molten magma, just like volcanoes are often portrayed in the movies. Others are more transitory, changing in depth or draining all-together depending on the pressure conditions within the system.
Typically, after an eruption, lava exposed to the atmosphere will cool into a solid plug of rock, trapping the volcano’s heat and gasses within. For a lava lake to form, Nicholson says, “the balance between heat coming up from within the vent system of the volcano must be perfectly balanced with the rate of cooling to keep the lava in its molten state.”
“They’re really just one phase of what’s called an open vent system,” Nicholson explains, a type of volcano that allows gasses from within the Earth to escape into the atmosphere. Because of that seepage, they’re regarded as less prone to explosive eruptions than closed vent systems—and a boon to volcanologists who are able to analyze the composition of the escaping gas for clues of what’s going on below the surface.
Mount Michael, isolated in the South Sandwich Islands—a British overseas territory— caught the interest of scientists in the late 1990s when a British Antarctic expedition noticed a strange pattern in the plume that regularly emanates from the peak. “The plume, which was unusually dense, was huffing and puffing,” says John Smellie, a British geologist. In 2001, he proposed in an academic paper the possibility of a lava lake in Mount Michael’s crater. In 2019, that possibility was firmed up by a new study using higher resolution satellite imagery. But no one had actually viewed the lake from Mount Michael on Saunders Island.
“The South Sandwich Islands, they’re tough to get to, tough to get ashore, tough to work on,” Smellie says. “You have to have a pretty good reason to go there.”
Crossing the ‘Furious Fifties’
The few hours Nicholson and her team spent on the rim of the crater were the culmination of months of planning and weeks of travel. Although it’s only 2,766 feet above sea level, the modest altitude of Mount Michael belies its extraordinary isolation.
“If you stand on Saunders Island,” says Nicholson, “your closest other humans are on the International Space Station. That’s the definition of remote.”
The team embarked last November from Stanley in the Falkland Islands aboard the Australis, a 75-foot steel-hulled vessel with Ben Wallis at the helm for the grueling 1266-mile passage to Saunders Island.
Just getting there, as Smellie says, may be the greater challenge than climbing the glaciated peak. At the 57th parallel south, Mount Michael sits directly downwind of the Drake Passage, right in the middle of the latitudes known as the “Furious 50s,” notorious to mariners for their unrelenting wind and ferocious storms.
“I’m a lot more traumatized about sailing now than before departure,” quips Joao Lages, a geochemist and volcanologist on the expedition, after enduring near constant seasickness enroute to the island.
Saunders Island is far beyond the reach of existing air support networks and is accessible only by boat. That means the evacuation time for any medical emergency would be seven to ten days—and that’s in good weather.
“What makes the South Sandwich Islands different is they’re outside the fence,” says Wallis, “There’s no one to come help you if you get in trouble.”
An island uninhabited, windblown and freezing
The island was discovered by Captain Cook in 1775, but never inhabited. The members of the expedition are among the first humans to have slept there. “More people have been to the moon than set foot on Saunders Island,” says Kieran Wood, an aerospace engineer and one of the team’s drone pilots. After establishing a basecamp on the windswept island, the team made two separate ascents to the crater’s rim in the span of a week to conduct the first fieldwork on the summit.
Despite the extreme conditions on the summit, which included 45-to-60 mile-per-hour winds and 90 percent humidity in the form of a miserable, thick, frozen fog, the team was able to collect gas, snow, and rock samples and operate drones, thermal cameras, a multi-gas sampling system, and other instruments.
“There was a window of one or two hours where we might expect to have reduced winds, better visibility,” Nicholson says. But to make the most of that window, the team had set out in gale force winds. “The wind was relentless. It was still blowing ash particles and hail in our faces. We could barely see our hand in front of our face,” Nicholson says.
Nicholson considers expeditions like this a crucial step toward a better globalized understanding of volcanoes. Several volcanoes around the world are “well instrumented,” she says, and serve as scientific laboratories. Even in its isolation, Mount Michael served as such a lab, if only for a handful of days. One of the expedition’s goals was to make the most of satellite capabilities, and she thinks Mount Michael filled in many blanks.
“We now have that anchor point in time, (and) now as we have satellite data come in, that anchor point will provide the context for us to interpret that data physically,” she says. “Projects like this tie these observations from space down to what we can measure on the ground, what we can picture and visualize.”
That, in turn, will enable scientists to better read what’s going on in the lava lake, much like reading a pressure gauge when the depth of the lava rises and falls. And that’s just one of Mount Michael’s secrets to be revealed.
“Standing inside the rim of the crater, being able to see just how steep the crater is, it told me straight away that it has had a much more explosive past than what we were seeing right then,” Nicholson says. “This volcano is a force to be reckoned with.”
More details to come on this story later this year on National Geographic Explorer on Disney and in National Geographic Magazine.
The author of 5 books, 3 of which are New York Times bestsellers. I’ve been published in more than 100 newspapers and magazines and am a frequent commentator on NPR.