Dozens of mini-earthquakes have rattled Alaska’s Mount Spurr over the past week, sparking fears among scientists that the towering 11,000-foot volcano may be on the verge of a major eruption.
According to the Alaska Volcano Observatory (AVO), at least 30 small quakes, some forming “swarms”, were recorded, indicating rising magma beneath the surface and increased pressure inside the volcano.
Officials warn that if Mount Spurr erupts, the event could be “explosive,” spewing multiple plumes of ash as high as 50,000 feet into the atmosphere. “Each ash-producing explosive episode would last three to four hours,” said Matt Haney, scientist-in-charge at the AVO, according to Daily Mail. “Nearby communities, including Anchorage, would be engulfed in a giant ash cloud”, Haney added.
Anchorage, home to more than 300,000 residents and located just 81 miles from the volcano, has been placed on emergency alert.
On March 20, the city raised its emergency planning level to Level 2, ramping up communication with the public and preparing to activate eruption protocols. Officials have urged residents to stockpile essentials like food, water, pet supplies and protective gear. Many have turned to buying N95 masks, protective goggles, and even respirators for pets.
The recent seismic activity builds on concerns dating back to April 2024, when Mount Spurr began exhibiting signs of unrest. By October 2024, the number of weekly quakes had risen from 30 to 125 and gas emissions from both the summit and a side vent, known as Crater Peak, significantly increased. That vent, notably, was the site of the last eruption in 1992, which blanketed Anchorage in ash and shut down the city’s airport for 20 hours.
In addition to the tremors, scientists have observed elevated emissions of carbon dioxide and sulfur dioxide, a clear signal that magma is heating water and gas deep below the surface — a precursor to eruption, according to Live Science. “This time period of unrest will eventually most likely end in an explosive eruption,” Haney warned.
Experts say if the volcano continues its current trajectory, the next likely sign of imminent eruption would be sustained volcanic tremor, a continuous seismic rumble that could last from minutes to days. “If we see tremor, that will be the next sign that Spurr is further progressing toward an eruption,” said Haney.
Meanwhile, local businesses are adapting. Anchorage pet store AK Bark reported selling more than 500 pairs of protective dog goggles in March, and it has already pre-sold 1,800 dog respirators. Residents have shared videos online of their pets in full ash gear, including goggles, booties, and protective clothing.
Mount Spurr’s summit crater hasn’t erupted in over 5,000 years, but Crater Peak, more active and with easier access to the surface, last erupted three times in 1992 alone. If another eruption does occur, scientists expect it will likely come from Crater Peak again, with a similar impact on Anchorage and nearby areas.
The National Transportation Safety Board and US Geological Survey continue to monitor the volcano closely.
As per Daily Mail, the city has already issued official guidance, especially for pet owners, to prepare for at least two weeks of disruption in case of a major eruption.