How to pack for sampling Earth’s hottest pockets

When the Fagradalsfjall volcano in Iceland awoke in spring 2021 after 815 years of slumber, the geochemists and petrologists at the University of Iceland knew they wanted a sample. It was a rare opportunity to get their hands on fresh lava that usually stays close to the mantle. But first they needed suitable safety gear and a plan.

Active volcanoes share some general safety hazards with one another, as well as with other fiery environments such as wildfires and burning vents. Yet each site is unique in its specific dangers. There is no international safety manual for eruptions, says Ed Marshall, a geochemist at the University of Iceland. Back in the 1970s, he adds, you would see a “guy in a T-shirt setting up his camp next to a vent of lava and just running in there with a scoop.” On the other end of the spectrum are people wearing aluminum foundry suits. And drones can now replace humans in some scenarios. How to safely sample Earth’s hottest bits comes down to site details and researchers’ goals, according to Marshall and other scientists who have done such adventurous work.

Sometimes you minimize

Fagradalsfjall is a relatively gentle volcano. Unlike an explosive volcano such as Mount Saint Helens, Fagradalsfjall “is kind of a toy volcano,” Marshall says. “It’s the least dangerous type of volcanism you can imagine.” Hiking paths circle the eruption site, and tourists book day trips from Reykjavik to visit it.

Because Fagradalsfjalls’s magma rises from the crust-mantle boundary, its isotopic composition reveals more about mantle chemical variability than lava flows studied previously, Marshall says. So from March to September 2021, when the volcano was active, he and his colleagues collected samples about every other day, and again when it erupted briefly in August 2022. They collected a total of about 130 samples, and they have their safety protocols down.

They first check the webcams, weather, and wind. They find the active lava flows, look at the direction of the volcanic gas plume, and plot their route in and out. “We plan to always stay upwind,” Marshall says. Gases in the plume are the number one danger. Carbon monoxide, sulfur dioxide, and hydrogen sulfide are poisonous, and oxygen levels might be low. The team carries a gas meter, and each person has a gas mask. If the meter alerts or the researchers smell hydrogen sulfide or sulfur dioxide, they put on the masks.

Once at the site, the person who’s doing the sampling suits up and another watches. When you’re wearing gear, Marshall says, it’s hard to be completely aware of things that are happening around you. The person watching, who doesn’t suit up, helps with awareness by staying close enough to assist the sampler but remaining out of danger.

The sampler puts on heavy-duty leather welding gear, open at the back. At Fagradalsfjall, there are no flames or flying lava, so more protection is unnecessary. The scientists just need to be comfortable enough to sample the lava from a little over 1 m away. “If you get to lava where the pole would be insufficient to keep you from getting scorched, then we wouldn’t sample it because it’s too dangerous,” Marshall says.

When standing next to the lava, the sampler must wear the gas mask and a heat helmet over it. Aluminized gloves protect the hands. Samplers use a custom-​made 11 kg pole with a scoop on the end to dig at the cooled surface and scoop the core of the lava flow—Marshall describes the texture as “marshmallowy”—into a bucket of water. The whole process takes about a minute. Water cools the lava so rapidly that it quenches the lava into a black glass, freezing all the chemicals in place and preventing crystallization.

Marshall thinks the researchers’ gear nicely balances safety, cost, and the ability to collect samples. They put on the necessary items and post a watcher to remain attuned to their environment. They prioritize getting in and out quickly. “We don’t spend enough time around the lava that we get heat exhausted,” Marshall says. “If you’re wearing much heavier-duty aluminized foundry suits, you can just hang out by the lava. But then the problem is you’re a turkey wrapped in aluminum foil, and you start cooking. By limiting the amount of time that we’re in front of the lava, we make everything a lot safer. And we need less equipment.”

Sometimes you maximize

In 2013, explorer George Kouronis led a National Geographic expedition to Turkmenistan and became the first person to descend into one of Earth’s most fiery environments: the Darvaza gas crater. Nicknamed Hell’s Gate, it is a 60-by-20-m pit of rocks and sand scattered with fires from natural gas vents that light up the Karakum Desert at night.

Kourounis gathered soil samples at the bottom of the crater for Stefan Green, a microbiologist who joined the expedition to analyze extremophile bacteria from Hell’s Gate. Microbes that prosper in such an extreme environment show how life could survive in extraterrestrial conditions that are hot, dry, and rich in methane.

Kourounis, who had long been drawn to the site, spent 2 years gathering sponsorship, funding, and permission to film his trip into the sinkhole. Adding to the challenge: before arriving, the team knew little more about the crater than what they could glean from a few pictures on the internet.

“How big is it? How deep? How many poisonous gases?” ask Frederick Schuett, owner of One Axe Pursuits, who was in charge of rigging for a safe traverse and descent. “We knew it was burning natural gas, so we’re thinking about methane, carbon dioxide, and carbon monoxide, but we weren’t really sure.” Other unknowns included whether the fires consume all available oxygen and the temperature profile of the crater. Methane tends to burn close to 2,000 °C, while the air between vents could be cooler. Schuett knew that heat exhaustion, with possible dizziness and fainting, could be a problem if Kourounis spent more than 10–15 min at high temperatures.

Given the uncertainty, the group planned for every possible risk. For clean air, Kourounis brought a self-contained breathing apparatus (SCBA), which includes an air tank and mask. To protect himself from flames and to reflect heat, he had a full-body aluminized suit with a helmet and gloves that are designed for working with molten metal. Noncorrosive and lightweight, the aluminum reflects about 95% of infrared heat.

The gear also included a multigas meter and two temperature probes. To enable Kourounis to rappel into the crater, the team procured a custom-​fabricated climbing harness made of Kevlar and ropes of Technora—a strong, Kevlar-like material that resists high heat and abrasion. Schuett also designed a rigging system that could pull Kourounis from the crater even if he passed out.

Once team members arrived at the crater, the heat pattern surprised them. Air flowed in a convection pattern—such that 100 °C air rose at the outer edges, while cooler air fell in the middle. The air above the middle of the crater dropped to 35 °C, cool enough for birds to dip in and out to catch bugs at night. The vents also burned cleaner than they expected, says Schuett. The fire burned off almost all the methane, and the team detected few gases otherwise.

Nevertheless, Kourounis wore all the gear as planned on his two descents to the crater floor. His gear made it possible to safely collect soil samples, but it also got in his way a bit. With the temperature around 50 °C on the crater floor, the suit felt like a “snowsuit on a hot summer day,” he says. He started heating up and felt close to heat exhaustion near the end of his longer trip, which was 17 min. He wore two portable cameras, one of which blocked his vision on one side. His gas alarm alerted, but he couldn’t see whether it detected methane, carbon monoxide, or low oxygen—because of the cumbersome helmet.

In January 2022, Turkmenistan’s president announced that he wants to extinguish the crater, and scientists in the country are coming up with plans to do so. Kourounis has been asked to visit the crater floor again while the vents are still aflame. If he does, he says he’ll still wear an aluminized suit and take an SCBA, “because you don’t want to breathe superheated air, even if it’s totally breathable.” And he’ll bring more equipment to measure gases.

Green says he would want more sampling trips and a more careful sampling strategy—one that tracks wind direction, methane level, and soil depth and moisture. Schuett would like a suit with a better seal on the wrists, ankles, and helmet. Since the 2013 expedition, he has designed such suits and included interior heat sensors to help detect heat exhaustion.

In addition, a few years ago, some engineers in Turkmenistan were lowered to the crater floor using a crane. Kourounis has been offered the use of one if he descends again, and he’s considering whether to go that route.

Sometimes you need a drone

In May 2018, fissures opened on the flanks of Hawaii’s Kilauea Volcano, and lava poured out and down to the sea. The summit then collapsed, and the empty crater left behind deepened from 85 m to 490 m. In July 2019, groundwater began seeping in. “There had never been a water lake at Kilauea in recorded history,” says Patricia Nadeau, a volcanologist with the US Geological Survey (USGS) who specializes in volcanic gases. The lake grew to 49 m deep, filled with over 750 million L of water.

“As a gas scientist, I’m thinking—sulfur dioxide dissolves in water,” Nadeau says. “I was pretty interested in figuring out how to sample the water, to track the gas chemistry.” Yet even though Kilauea is an approachable volcano—safe enough to host a national park on top of it—the crater was now far too steep. No one could walk to the lake to get a sample.

Nadeau and her colleagues talked about hanging a sampler off a helicopter. But using a helicopter was risky because of the potential lack of oxygen at the bottom of the crater, the water’s high temperature (70–80 °C), and the lack of a safe place to land in an emergency. “That’s when the discussion about using a drone came up,” Nadeau says. They had previously used drones, or unmanned aircraft systems (UAS), to track lava flow and measure gas chemistry, but no one at the USGS had used one to collect water at a volcanic lake.

Nadeau and her group asked the park and a Native Hawaiian council for permission to sample—the volcano is a sacred site to indigenous Hawaiians—and she and her colleagues trained to operate the UAS. In October 2019, they stood at the crater rim and piloted a UAS to fly down about a kilometer to the lake and dip a heat-resistant sampling tube into the water. They repeated the sampling in January 2020 and October 2020. But the volcano erupted again in December 2020, before they could sample a fourth time, and the lake boiled away.

Since then, the use of UAS for dangerous and otherwise impossible sampling has increased, at Kilauea and elsewhere. Nadeau’s group flies UAS into concentrated bits of the volcanic gas plume, “which can have hundreds of parts per million of sulfur dioxide,” Nadeau says. “You don’t want to put a person in that.” The crater is so deep and steep sided that all gas measurements of the current eruption need to be taken by drone. After the water lake boiled away in 2020, Kilauea’s summit crater refilled as a lava lake, and some of Nadeau’s colleagues at USGS have discussed the idea of using a drone to pick up bits of lava off the top of it.

“Looking into the future, I think we’ll figure stuff out as questions present themselves,” Nadeau says. “We’ll just make it happen.”

Such optimism and flexibility are necessities for any scientist studying the hottest spots on Earth. Volcanoes, wildfires, and burning vents remake their environments daily, and the people dedicated to sampling them must be similarly nimble. Site details, risks, and goals all influence decisions about the appropriate safety gear for the occasion. Scientists need to be mindful of heat, gases, and weather. If they get close enough, they need protective gear—knowing that the gear itself can limit their awareness. And if they can’t get close enough, maybe a drone can.

Louisa Dalton is a freelance writer based in Virginia who covers chemistry. A version of this story first appeared in ACS Chemical Health & Safety: cenm.ag/safe-sample