Major U.S. City Could Be Struck by Volcano That Hasn’t Erupted in 800 Years

Scientists have reported seeing signs of a chance for the volcano to erupt at any given time. As many people visit dormant volcanoes, they and nearby residents should be wary of it as they could get caught up in the crossfire. 

With a dormant volcano, people assume this means that it is never going to erupt. This isn’t true. Even a dormant volcano is still at risk of erupting — it just hasn’t erupted in a long time. 

This is the case for Mount Etna and Mount Stromboli, both volcanoes in Italy. They erupted in 2024 and caused travel chaos and turmoil for locals. Flights were canceled for people trying to get to and from the area, leaving thousands of passengers stranded.

It sits very close to some cities and houses but hasn’t had any major eruptions in around 4,000 years. Residents who live near the volcano thought they were safe until recent updates changed this. 

While the latest eruption happened 800 years ago, there is also evidence of an eruption 1,150 years ago. A 2010 research paper found ash in deposits in Sitka Sound. The authors wrote that a similar eruption would “pose significant risk to local population centers.”

The indigenous people, the Tlingit, lived near the mountain and called it L’ux, which means “flash” or “blinking.” They likely discovered the mountain while it was smoking or erupting.

The Alaska Volcano Observatory has raised the threat level of the volcano erupting, and it plans to install several seismic instruments on Mount Edgecumbe.

Hikers have even reported seeing gas bubbling from the ground near Mount Edgecumbe. Satellite radar measurements have also shown the ground around the volcano bulging upward.

Moving magma can either force its way along the cracks or become an expanding pool of melt at depth. Both of these processes cause minor earthquakes and give scientists reason to believe that something could be happening. 

The city of Sitka is about 15 miles away from the sleeping volcano. While improbable, Sitka risks being the nearest city to a possible eruption. “It does have some signs of unrest,” said Hannah Dietterich, a research geophysicist for the U.S. Geological Survey at the Alaska Volcano Observatory.

Even if humans do not report earthquakes, seismometers can easily pick these up and report the findings back to the scientists. The scientists can then record the data and try to decipher if or when the volcano will erupt. 

While this is good news, there is still a slight risk of an eruption. In the meantime, the new instruments the Alaska Volcano Observatory installed will keep track of any activity that poses a greater risk. All in all, it is still unlikely that Mount Edgecumbe will erupt any time soon.

After the small earthquakes in 2022, experts reviewed satellite radar measurements dating back to 2014. The researchers concluded that the ground near the mountain was bulging outward at a faster rate than any other volcano in Alaska. The growth has slowed down since 2022.

Scientists are using accurate ground sensors, which means they will see changes in the ground hour by hour. Solely relying on satellite measurements would mean waiting for days or weeks to see any changes in the ground. The seismic instruments installed near the volcano can detect earthquakes smaller than magnitude 1.

“Often, the earthquakes you get at a volcano aren’t usually the ones that anyone feels. When we have more seismometers on a volcano, we’re able to see any movement of fluid or magma, or even faulting – structural things that can produce very, very small earthquakes,” said Dietterich.

There are four seismic stations and four sites to measure how the ground is deforming as the magma moves deeper into the ground. “There’s signs that there is magma that’s come into the system very deep. We’re talking six miles below the volcano. And so we want to be sure to be monitoring it as best we can,” said Dietterich.

Scientists also investigated reports of gas bubbling from the ground near the volcano. The researchers took samples of the gas and submitted them for review. They looked for signs that the gas was associated with the magma. Perhaps the gas would indicate how far below the surface the magma was.

Dietterich and her team were searching for a volcanic signature in the gas samples. If they found a signature, it could have been a sign of a path between the surface and the magma 20 feet underground. However, Dietterich said: “It looks like there’s no strong evidence for a volcanic signature to any of the gasses.”

He placed some tires around the volcano and set them on fire, which caused black smoke to rise to the top of the volcano, making it look like it was close to eruption. Thankfully, it was just a prank, and the volcano didn’t actually erupt. 

It’s even got volcanologists worried, with some saying Mount Rainier keeps them up at night with the worry of what might happen to the residents and areas surrounding the volcano. 

They have said that the seismometers can pick up any changes in movement pretty quickly, so residents could get to safety very quickly before any eruptions or destruction would happen. 

Throughout the last twenty years, many volcanoes have had magma rising from them. While in some cases, the volcanoes have erupted, in the majority of cases, they have remained dormant, and scientists are hoping this will put people’s minds at ease.

The instruments leave potential for research opportunities. Edgecumbe is the easternmost monitored volcano in Alaska. It is also near a transform fault. Dietterich said that our knowledge of volcanoes that sit along transform faults is limited.

Alaska’s most active volcanoes are generally west of Anchorage. These volcanoes sit where the Pacific tectonic plate slides beneath the North American plate in a subduction zone. Dietterich said there is the possibility of geology work on Edgecumbe, but none has been scheduled yet.