Scientists are keeping a close eye on a giant volcano in Alaska that appears to be ‘moving closer to an eruption.’
On March 7, Mount Spurr, an 11,000-foot-tall stratovolcano that sits 81 miles west of Anchorage, began releasing elevated levels of gas from its summit and a side vent that last erupted in 1992.
These emissions are the latest development in a period of unrest this volcano has been experiencing since April 2024, when it started shuddering with small earthquakes — the first clue that new magma was rising toward the volcano’s vents.
That seismic activity has continued through to today, and with the recent increase in volcanic gas emissions, scientists say Mount Spurr could blow in a matter of ‘weeks or months.’
The eruption would most likely occur at the Crater Peak side vent, and ‘it would be explosive,’ Matt Haney, scientist-in-charge at the Alaska Volcano Observatory (AVO) at US Geological Survey (USGS) told DailyMail.com.
This event would spew multiple plumes of ash rising as high as 50,000 feet into the air, Haney said.
Each ash-producing explosive episode would last three to four hours, and the resulting cloud could blanket the city of Anchorage and other nearby communities in a thick layer of dust.
The eruption would also produce destructive mudslides and avalanches volcanic debris racing down the volcano’s side at over 200 miles per hour, ‘but fortunately, there are not any communities in that radius that would be affected,’ Haney said.
Scientists warn Mount Spurr in Alaska could erupt within the next few weeks or months. It last erupted in 1992 (pictured)
The USGS has the volcano under ‘advisory,’ meaning it ‘is exhibiting signs of elevated unrest.’
‘We have been tracking this for about a year,’ Haney said.
Between April and February, Mount Spurr exhibited three key signs of a forthcoming eruption: increased seismic activity, swelling of the volcano’s surface and snow and ice melt near the summit.
Last month, the AVO said the volcano’s activity was equally as likely to die down as it was to lead to an eruption.
But on March 7, scientists flew over Mount Spurr to measure the gases rising from its two vents. For the first time since the heightened activity began, they detected gas emissions that were ‘above background,’ Haney said.
They flew over again on March 11 to check their measurements, and confirmed that the volcano was producing higher-than-average levels of gas.
‘With the new measurement of gas emissions above backgrounds, that led us to conclude that an eruption like the two recent ones was the most likely scenario,’ Haney said.
Mount Spurr last erupted in 1992 and 1953, and both events were produced by the Crater Peak side vent.
In recent days, Mount Spurr has been releasing elevated levels of gas and has continued to experience an uptick in seismic activity
Mount Spurr is one of 53 volcanoes in Alaska. It sits 81 miles from Anchorage, which is home to 300,000 people
Haney and his colleagues estimate that the volcano’s summit crater hasn’t erupted in the last 5,000 years. So when Mount Spurr blows again, it will most likely be from the side vent, he said.
In June 1992, the Crater Peak flank vent awoke from nearly 40 years of dormancy and erupted after 10 months of elevated seismic activity, according to the USGS.
This event covered the city of Anchorage, home to nearly 300,000 people, in an eighth of an inch of ash.
The skies darkened in the middle of the day due to the enormous cloud of dust and gas, and the city’s airport was forced to shut down for 20 hours.
Crater Peak then erupted two more times, once in August and again in September.
The Municipality of Anchorage reported nearly $2 million in damages, office closures and cleanup costs from the August eruption, according to the National Oceanic and Atmospheric Administration (NOAA).
No one was killed by these events directly. But two heart attacks, one fatal, from shoveling ashfall were reported in Anchorage.
Breathing in ash also poses a health hazards. The tiny particles can work their way deep into the lungs, worsening symptoms for people with respiratory conditions such as asthma or bronchitis.
While all signs point to an eruption in the near future, it’s impossible to say exactly when it will occur.
But if Mount Spurr’s activity continues to ramp up, the next sign of an eruption will be a volcanic tremor, Haney said.
This would be different from the brief, shallow earthquakes this volcano has already been experiencing.
A volcanic tremor is a longer stretch of ongoing shaking that can persist for minutes to days.
It occurs when magma beneath the volcano begins rising toward the surface as the eruption grows imminent.
Back in 1992, Mount Spurr was rocked by a volcanic tremor about three weeks before the June eruption, so this type of seismic activity could signal that the volcano will blow in just a few weeks.
However, other volcanoes have experienced longer periods between a volcanic tremor and an eruption, such as the nearby Mount Readout.
This volcano experienced a volcanic tremors for two months before it finally blew in 2009.
While forecasting an eruption is filled with uncertainty, Haney and his colleagues will continue to closely monitor Mount Spurr to glean a rough idea of when it is most likely to erupt.
