A magnitude 4.6 earthquake has struck just miles from Mount Spurr, the restless Alaskan volcano already on scientists’ radar, intensifying concerns that an eruption could be on the horizon.
The U.S. Geological Survey recorded the quake at 10:38 a.m. local time near Petersville, roughly 86 miles from Mount Spurr and 34 miles north of Skwentna. Shaking was felt across Anchorage and the Mat-Su Valley, with the Alaska Earthquake Center pinpointing its depth at 52.4 miles.
Mount Spurr has sat under an “Advisory” alert for months due to persistent low-level seismic rumblings, punctuated by occasional small quakes beneath its summit. In March, activity spiked enough for the Alaska Volcano Observatory to briefly raise its alert level to “Watch,” warning an eruption could happen at any moment.
Scientific studies — including research published in Nature — reveal that earthquakes in close proximity can tip a restless volcano into eruption, especially when magma pressure and underground gas levels are already high. Both conditions are present at Mount Spurr today.
“Fluctuations in unrest are common at volcanoes,” the Alaska Volcano Observatory noted, “and eruptive activity remains possible, though unlikely.” Still, experts caution that the volcano’s 1992 eruption followed a similar cycle of pauses and surges.
If Mount Spurr does blow, Crater Peak — one of its side vents — is the most likely source. An explosion there could hurl ash clouds 50,000 feet into the air, smother Anchorage in volcanic debris, and unleash dangerous mudflows and avalanches.
Compounding the threat, the nearby Broad Pass Thrust Fault is active and capable of producing massive quakes up to magnitude 7.8, adding yet another layer of seismic risk to the region.
For now, Mount Spurr remains under close watch. Authorities urge Alaskans to monitor updates from USGS and the Alaska Volcano Observatory as this volatile situation unfolds.