Near-term chances of an eruption at Alaska's Mount Spurr volcano now considered 'extremely low'

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ANCHORAGE, Alaska (AP) — Officials lowered the alert level for a volcano near Alaska’s largest city to normal Wednesday, which they said indicates that Mount Spurr is “quiet” months after showing signs of activity that raised the possibility of an eruption.

Over the past few months, signs of unrest at the 11,070-foot (3,374-meter) volcano near Anchorage have gradually decreased, according to the Alaska Volcano Observatory, which added that no ground deformation has been detected since March. The observatory characterized the near-term chances of an eruption as “extremely low.”

It said small earthquakes continued to occur more frequently than before a period of unrest began in early 2024, and that volcanic gases were still being released. But the center said this is normal for volcanoes where magma has moved upward but has not erupted.

“Minor gas emissions and a slightly higher number of small earthquakes could persist for many months to several years,” the observatory said.

Mount Spurr is one of 53 volcanoes in Alaska that have been active within the last 250 years. The volcano has two main vents: the last known eruption from the summit vent was more than 5,000 years ago, while there were eruptions from the Crater Peak vent in 1953 and 1992, the observatory has said.

In October, the observatory raised its alert status for Mount Spurr from green, or normal, to a yellow advisory status when an increase in seismic activity became pronounced and a ground deformation was spotted in satellite data.

In March, the observatory said it had measured “significantly elevated volcanic gas emissions" from Mount Spurr and said signs indicated an eruption was likely, though not certain, in the weeks or months ahead. That prompted Anchorage's mayor to encourage residents to be prepared in case of an eruption that could produce ashfall in the city. Anchorage is about 80 miles (129 kilometers) from the volcano.

Volcanic ash is angular and sharp and has been used as an industrial abrasive. The powdered rock can cause a jet engine to shut down.