By STACY LIBERATORE, U.S. SCIENCE & TECHNOLOGY EDITOR
An earthquake was detected just miles north of an Alaskan volcano showing signs of unrest and potential eruption.
The US Geological Survey reported a magnitude 4.6 quake near Petersville, about 86 miles from Mount Spurr.
The Alaska Earthquake Center said: ‘We have reviewed a M4.6 earthquake that occurred at 10:38 a.m. local time, 52.4 miles deep and 34 miles north of Skwentna.’
‘This event was felt throughout Anchorage and the Matanuska-Susitna region,’ the center added. Anchorage sites are located more than 100 miles from the epicenter.
The USGS has received nearly 200 reports of shaking from the sparsely populated area.
Mount Spurr is currently under an ‘Advisory’ due to low-level unrest, with occasional small earthquakes detected beneath the volcano.
A 2021 study published in Nature found that most volcanoes, especially those already showing signs of unrest like Mount Spurr, can be triggered to erupt by nearby earthquakes.
The study notes that this is more likely when factors such as magma pressure and underground gas buildup are already present.
An earthquake was detected just miles north of an Alaskan volcano that is set to erupt. The US Geological Survey detected a 4.6 magnitude quake in Petersville, about 48 miles from Mount Spurr. Pictured is the volcano’s last eruption in 1992
Mount Spurr is currently under an ‘Advisory’ due to low-level unrest, with occasional small earthquakes detected beneath the volcano. The volcano was under ‘Watch’ in March when scientists expected it to erupt at any moment
The USGS detected the earthquake 52 miles below the surface, and at this depth, the quake tends to spread energy more widely.
However, the shaking may feel less violent at the surface unless the magnitude is large.
Melissa Palmer posted on Facebook: ‘[I] felt it in Anchorage (Airport Heights).’
Others reported movement in Anchorage’s Sand Lake neighborhood and north of Healy.
The region around Petersville, Alaska, is influenced by the Broad Pass thrust fault, a southeast-vergent thrust fault that formed a wedge-top basin called the Peters Hills basin.
The Broad Pass thrust fault is considered active and could potentially generate earthquakes in the magnitude 7.6 to 7.8 range, posing a potential seismic hazard.
Anchorage is home to nearly 300,000 people who have been keeping a close eye on Mount Spurr since March, when scientists warned an eruption was imminent.
The Alaska Volcano Observatory (AVO) issued the latest update on Tuesday, saying: ‘Low-level unrest continues at Mount Spurr with occasional, small earthquakes occurring beneath the volcano.
Wednesday’s earthquake was felt in Anchorage, which sits more than 100 miles from the epicenter
‘Nothing was observed in partly cloudy to clear satellite images over the past day. Clear webcam views of Mount Spurr’s summit crater showed minor vapor emissions.
AVO also noted that ‘fluctuations in unrest are common at volcanoes and eruptive activity remains possible, but unlikely.’
The agency explained that there were periods when unrest at Mount Spurr slowed in 1992 before its eruptions.
However, these periods were not sustained, and seismic activity fluctuated leading up to the eruptive events.
When the volcano was under a ‘Watch, ‘ it began releasing elevated levels of gas from its summit and a side vent that last erupted in 1992.
During that month, Matt Haney, scientist-in-charge at the AVO, told DailyMail.com that the eruption would most likely occur at the Crater Peak side vent, and ‘it would be explosive.
This event would spew multiple plumes of ash rising as high as 50,000 feet into the air, Haney said.
Each ash-producing explosive episode would last three to four hours, and the resulting cloud could blanket the city of Anchorage and other nearby communities in a thick layer of dust.
The eruption would also produce destructive mudslides and avalanches of volcanic debris racing down the volcano’s side at over 200 miles per hour. ‘Fortunately, there are no communities in that radius that would be affected,’ Haney said.
This article was originally published by a www.dailymail.co.uk . Read the Original article here. .