Mount Spurr trembles again: Scientists see 50% eruption risk due to rising Earthquakes

Alaska’s Mount Spurr Shows Signs of Possible Eruption (Image: Alaska

Mount Spurr, a snow-covered volcano in Alaska, may be preparing to erupt. The volcano, located 77 miles (124 kilometres) from Anchorage, has experienced ongoing small earthquakes since April 2024, according to the Alaska Volcano Observatory (AVO). Scientists believe this activity could be caused by magma moving beneath the surface. While the movement may stop without an eruption, experts warn that the volcano could also erupt in the near future.

Matt Haney, the scientist-in-charge at AVO, stated that the number of earthquakes has increased in recent months. "It’s had a higher-than-normal number of earthquakes for many months," Haney said. "But over the past month, that itself increased, and also the location of the earthquakes changed." The seismic activity has shifted from near the summit to a vent called Crater Peak, about 2 miles (3 kilometres) down the slope. This vent last erupted in 1992, producing an ash cloud that reached 65,000 feet (20,000 metres). Scientists estimate a 50% chance of a similar event occurring again.

Possible eruption scenarios

Mount Spurr has shown signs of unrest before without erupting. Between 2004 and 2006, earthquake activity increased but eventually subsided. Haney explained that the most likely outcomes are either an eruption at Crater Peak or the magma movement stopping without an eruption. The least likely scenario is an eruption from the summit crater, which has remained inactive for 5,000 years.

If an eruption does occur, it could release large ash clouds and pyroclastic flows—fast-moving avalanches of hot gas, ash, and rock. Melting ice and snow could also trigger mudflows known as lahars. However, no communities are directly in the path of these hazards.

Potential impact on travel

The biggest concern for residents and travellers is ashfall. During the 1992 eruption, Anchorage’s airport was temporarily closed, and the city was covered in a thin layer of ash. Haney noted that an eruption today could be even more disruptive, as more flights travel through Alaska between North America and Asia.

Scientists are closely monitoring the volcano for further changes. Haney explained that before the 1992 eruption, the earthquakes turned into continuous tremors, a sign of an impending eruption. "If we saw this more long-duration shaking of the volcano in our seismic data, that would be a more clear indication that the unrest is progressing toward a more certain eruption," he said.