Unrest continues at Mount Spurr, the closest active volcano to Alaska’s population centers, and scientists at the Alaska Volcano Observatory are still watching for a possible eruption.
Starting in the spring of 2024, the researchers noticed an increase in small earthquakes at the volcano, which sits on the west side of Cook Inlet about 75 miles from Anchorage. Spurr was also growing outward, and a lake had formed in its summit crater.
The Alaska Volcano Observatory raised its code for Spurr to yellow, or "advisory" status, in October.
Since then, the elevated seismic activity at Spurr has continued, said Matt Haney, the observatory’s scientist in charge.
“We locate, these days, up to 100 earthquakes per week or even more at the volcano,” Haney said Tuesday.
The earthquakes remain small, but there’ve been many more than usual since October. Over the same time period, the observatory has also measured the volcano inflating, like a balloon, by about two and a half inches, Haney said.
Still, at this point, Spurr could go either way, with equal chances that it erupts or doesn’t, Haney said. Longer, sustained shaking, called volcanic tremors, would tip the odds more in favor of an eruption, he said.
“Volcanic tremor is a continuous shaking of the ground that can go on for minutes or tens of minutes or even perhaps an hour,” Haney said.
That would likely bump Spurr’s status from yellow to orange, or “watch,” status, Haney said.
Observatory staff are watching Spurr around the clock and conducting occasional flights over the volcano to test the gases coming out of its vents. So far, Haney said, they have not seen elevated levels of sulphur, which would be another indication that an eruption is coming.
Meanwhile, public attention on Spurr has only grown since October, Haney said.
“I think this has caught people's attention that here we are, you know, 2025, and we're seeing now another episode of unrest at Anchorage’s closest volcano," Haney said. “And so this is a reminder of how it is in Alaska.”
