The largest active volcano in Washington state has been rocked by a series of earthquakes, putting experts on high alert.
Mount Adams is a 12,000-foot-tall stratovolcano located in south-central Washington, about 55 miles southwest of the city of Yakima.
This volcano is considered a ‘high threat’ due to its ability to trigger landslides, debris avalanches and mudflow that can travel up to 50 miles per hour down the slope, which would put thousands of people at risk.
Although this volcano hasn’t erupted for about 1,000 years, ‘it will assuredly erupt again,’ US Geological Survey (USGS) experts say.
But it’s impossible to say exactly when it will blow, which is why scientists have established monitoring stations around Mount Adams to track its seismic activity.
Between September and October last year, these monitors detected nine earthquakes ranging from magnitude 0.9 to 2.0 around the volcano.
Mount Adams typically only experiences one earthquake every two to three years, according to the USGS.
While increased seismic activity can be a sign that a volcano is about to blow, experts have stressed that this series of tremors appears to be ‘normal background activity’ and does not mean an eruption from Mount Adams is imminent.
Mount Adams, the largest active volcano in Washington state, was rocked by a series of nine earthquakes between September and October last year
But the biggest threat to people living near this volcano isn’t an explosive eruption.
It’s actually avalanches, landslides and lahars, or muddy flows of rock, ash and ice that ‘surge downstream like rapidly flowing concrete’ and can occur during eruptive or non-eruptive periods, according to the USGS.
‘The ice-capped summit conceals large volumes of hydrothermally weakened rock, and future landslides of this weakened rock could generate far-traveled lahars,’ USGS officials wrote.
In light of the recent earthquakes, scientists have installed three additional monitoring stations around the volcano to keep a closer eye on it.
‘We went up and worked with the forest service to put three additional temporary stations in,’ Holly Weiss-Racine, the outreach coordinator for the Cascades Volcano Observatory (CVO), told KGW8.
‘They are solar powered, so they’ll be able to tell us when there is an earthquake,’ she added.
These additional stations will help scientists at CVO and the Pacific Northwest Seismic Network (PNSN) investigate the size, location and depth of the quakes, according to the USGS.
‘This will improve our ability to locate smaller earthquakes with more certainty and assist in understanding the cause of these earthquakes. The results of our findings will determine if any additional actions are needed,’ USGS officials wrote in a statement.
The biggest threats to people living near this volcano are avalanches, landslides and lahars, or muddy flows of rock, ash and ice that ‘surge downstream like rapidly flowing concrete’ and can occur during eruptive or non-eruptive periods, according to the USGS
Since October, the seismic activity around Mount Adams has died down significantly. But researchers will still watch the volcano closely to see if it picks back up again.
In addition to helping scientists assess Mount Adams’ likelihood of erupting, the new monitors will also help them answer longstanding questions about this volcano, Weiss-Racine said.
‘We don’t have a lot of background information on Mount Adams, we’ve been monitoring the mount for the last 42 years, but the volcano has been in existence for hundreds of thousands of years,’ she said.
For example, these monitors should help researchers determine how active Mount Adams really is.
In some cases, earthquakes near volcanoes can trigger eruptions.
But this only occurs if the quake is large (greater than magnitude 6) and the volcano is already poised to erupt.
When those conditions are met, the quake could cause dissolved gases to come out of the magma similarly to a shaken soda bottle, which increases the pressure inside the volcano and may lead to an eruption.
But these nine quakes were far too small to trigger an eruption.
Mount Adams formed roughly 520,000 years ago. It’s located roughly 70 miles northeast of Vancouver, Washington and Portland, Oregon.
Even through Mount Adams is considered a ‘high threat’ volcano, it hasn’t erupted for thousands of years.
Scientists estimated that its most recent eruption occurred sometime between 3,800 and 7,600 years ago.
And throughout its history, Mount Adams has mainly produced effusive eruptions, which are different from explosive eruptions in that they do not send lava, gas and ash shooting into the sky, but rather form slow-moving lava flows that creep down the volcano’s sides.
