Life and Death on the Lighthouse of the Mediterranean

If you stand at the summit at night, and you turn your flashlight off, all you can see are diamantine flecks shimmering in the dark. In that moment, you are floating, untethered, in an endless inky pool. The inevitable rumblings of the blackened earth beneath your feet eventually remind you that you remain on this planet. And when a jet of incandescent molten rock shoots skyward and illuminates the land like a flare, you feel as if you are staring down a dragon.

For those seeking to experience the raw and almost preternatural power of a volcano, you would be hard-pressed to find a better place than Stromboli, northwest of the toe of Italy’s boot and aptly known as the Lighthouse of the Mediterranean.

Rising a mere 3,000 feet above the waves of the Tyrrhenian Sea, the seemingly diminutive volcanic isle is famed for its near-continuous summit explosions. Most volcanoes spend much of their lifetime in a state of quiescence, but Stromboli bucks that trend. “It’s always active,” said Maurizio Ripepe, a geophysicist at the University of Florence in Italy. “I always say it’s the most reliable thing in Italy. It’s not like the trains.”

Stromboli is also home to a few hundred full-time residents. Their relationship with the volcano is largely cordial. Its regular explosive activity is confined to the summit, and a slope named the Sciara del Fuoco (“Stream of Fire”) harmlessly funnels superheated debris into the sea. The frequent window-rattling booms have become barely noticeable background noise, while its effervescence has proved highly attractive to paying tourists.

But the volcano is capable of acts of utter devastation. Rare but especially fierce blasts have killed people both at the summit and on its slopes. That danger makes Stromboli a resplendent place punctuated with moments of terror. Gaia Squarci, a photographer and videographer who first visited the island when she was 17, said that there is always “a calm, with a tension underneath.”

Everyone has a unique relationship with this paradoxical landscape. Scientists approach Stromboli as detectives. They hope to understand how it works by investigating its various viscera, a task aided by both its hyperactivity and its easy accessibility. “There are not so many volcanoes that you can go up to the summit, you work all day long, then you are only one hour from beer, pizza, good food,” said Dr. Ripepe.

Small explosions rock Stromboli’s summit all the time. Although a safe environment to work in for the most part, scientists are acutely aware that the volcano is capable of unleashing more potent explosions. These blasts, referred to as paroxysms, are considered to be a major threat. If they are powerful enough to dislodge part of the volcano, some can even trigger tsunamis.

Although the volcano has been relatively calm during the past half-century, the last few years have seen a return to violent form. In July 2019, a paroxysm killed a hiker and injured several others. The next month, another shook the island, but fortunately no one died that time. The authorities, fearing further paroxysms, subsequently closed the summit to visitors.

Jacopo Crimi, originally from Milan, was often brought to the island as a child by his parents. Today, he lives there, helping scientists present and share their work with their peers, clients and the general public. He describes living on Stromboli as a bit like being on one of the miniature planets in the universe of “The Little Prince,” the story by Antoine de Saint-Exupéry where the eponymous boy visits a number of lonely worlds.

Mr. Crimi says residents get to know the volcano, and its personality, as if it were a living thing. “It’s strange. It’s like a person,” he said. “You really miss it when you leave here. You feel lost.”

Travelers will always want to visit the island too, because erupting volcanoes provide a spectacle like no other. “We love danger, in some ways. It lets us feel immortal,” Mr. Crimi said. “It brings fear and joy together.”

The human presence makes volcanologists nervous. The volcano is nearly two miles tall, but only the uppermost part is above water. “They’re not living at the base of the volcano,” said Dr. Ripepe. “They’re living at the top of the volcano,” right next to its magmatic maw. No one on the island is far from harm’s way.

The overarching goal of the science of volcanology is to detect warning signs of an eruption, allowing anyone in danger to protect themselves. Volcanoes usually twitch and convulse before an eruption, but some dangerous phenomena give no discernible fanfare. For example, a pressure cooker-like bomb of underground water exploded without warning on New Zealand’s Whakaari/White Island volcano on Dec. 9, 2019, killing 22 visitors.

Stromboli’s eternal effervescence makes it a fantastic natural laboratory to trial attempts at eruption forecasting. Could the island’s own explosions, which happen rather suddenly, be seen coming?

It’s known that many volcanoes inflate when magma rises into them. This doesn’t always mean an eruption is forthcoming, but sometimes it does. Stromboli is no exception.

Devices that measure the changing shape of the volcano have been recording its metamorphosis for two decades. And scientists have noticed Stromboli inflates not at random, but every time the volcano is about to explode.

The inflation in this case appears to happen when the gases dissolved in the ascending magma escape into a lower pressure environment within the volcano’s shallow conduit, the esophagus-like passageway to the surface. Despite the erratic nature of Stromboli, “there is a rule in the chaos,” Dr. Ripepe said.

The scientists’ discovery was published in the journal Nature Communications in March, but an early warning system based on their data has been up and running since October 2019. If the volcano inflates in a way that indicates a paroxysm is coming, an automated alert is sent to the civil authorities and volcanologists, who then activate a series of sirens.

From the moment the signal is detected, everyone has up to 10 minutes to react before the paroxysm arrives. That may be sufficient to save the lives of many, either from the paroxysm itself or any subsequent tsunami. But it’s not a panacea. “If you are at the summit, there is no way to survive,” said Dr. Ripepe. Either the explosion’s shock wave will crush your internal organs, or the hot ash and gas will asphyxiate you. He and his colleagues are now hoping to find other precursors that will give people hours to get to safety.

Deciphering the complex series of grumbles and twitches exhibited by volcanoes in the run up to an eruption is rarely straightforward. But when efforts to identify precursors to volcanic violence are successful, it can provide salvation.

Take La Soufrière, a volcano on the Caribbean island of St. Vincent, as an example. It had been erupting in a calm and harmless manner since last December. But suspicious seismic activity in late March and early April was interpreted by scientists as a sign that something explosive was on its way. They convinced the government to order an evacuation of tens of thousands of people living in the volcano’s shadow on April 8. The very next day, the first in a series of catastrophic blasts rocked La Soufrière. Thanks to that early warning and subsequent exodus, no lives were lost to the volcano’s rage.

No matter what advances are made in eruption forecasting, Stromboli, like all volcanoes, remains capable of surprising everyone. “It’s humbling, the fact that we can get better and better at predicting patterns of behavior, but there will always be a high degree of unpredictability,” said Ms. Squarci.

According to Mr. Crimi, plenty of Stromboli’s longtime residents, including those who rely on tourism for their income, don’t want to engage with volcanologists, as they are seen to challenge the island-wide illusion that the volcano can do no harm.

But for some, the knowledge that the specter of death always exists is a thing of counterintuitive beauty. Scientists can try to comprehend Stromboli, but nothing they will do will alter the volcano’s actions.

“The volcano wrote the chapters of the island’s history,” said Ms. Squarci — and it will be the author of the island’s future, too.