Washington’s notorious volcano is best known for its ‘cataclysmic’ 1980 eruption, which brought devastation and destruction that stretched on for miles, and visible ash fall nearly 1,000 miles away. Scientists say it's recharging - but there's no sign yet of imminent eruption

Scientists say Mount St Helens is RECHARGING

Since mid-April, small earthquakes have been cropping up deep beneath Mount St Helens at ‘relatively high rates,’ bringing roughly one tremor every few hours.

In the last 30 days, scientists have located 55 seismic events in the vicinity, and say there may be well over 100 earthquakes linked to the swarm so far.

The activity falls in line with magma recharge thought to be underway since 2008.

But, don’t start panicking just yet – for now, scientists say there’s no sign of ‘imminent eruptive activity.’

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Washington’s notorious volcano is best known for its ‘cataclysmic’ 1980 eruption, which brought devastation and destruction that stretched on for miles, and visible ash fall nearly 1,000 miles away. Scientists say it's recharging - but there's no sign yet of imminent eruption

Washington’s notorious volcano is best known for its ‘cataclysmic’ 1980 eruption, which brought devastation and destruction that stretched on for miles, and visible ash fall nearly 1,000 miles away. Scientists say it's recharging - but there's no sign yet of imminent eruption

Washington’s notorious volcano is best known for its ‘cataclysmic’ 1980 eruption, which brought devastation and destruction that stretched on for miles, and visible ash fall nearly 1,000 miles away. Scientists say it’s recharging – but there’s no sign yet of imminent eruption

THE NEW SWARM

Scientists first began detecting small earthquakes beneath Mount St Helens on April 21.

But, they estimate the ‘uptick’ started as early as April 16, and was definitely underway by the 18th.

The largest so far was a magnitude 1.3, and most have occurred between sea level and 3 mi (5 km) below sea level (approximately 2-7 km below the surface), according to USGS.

The activity mirrors swarms that occurred this past November and almost exactly a year ago in March-May, which brought low-magnitude earthquakes at a rate of about 1-2 quakes per hour.

Scientists with the Cascades Volcano Observatory (CVO) and the Pacific Northwest Seismic Network (PNSN) first detected the earthquakes on April 21, according to the USGS.

Deep snow this past winter left the monitoring sites buried, and knocked out telemetry and power.

But, once everything had been restored to nearly full capacity, the network immediately began picking up signs of small earthquakes at a rate of one quake every few hours.

The scientists have found ‘good evidence’ to suggest this swarm began as early as April 16, and was definitely underway by the 18th.

The largest so far was a magnitude 1.3, and most have occurred between sea level and 3 mi (5 km) below sea level (approximately 2-7 km below the surface), according to USGS.

So far, though, scientists have not detected any deformation or gas signals.

In the last 30 days, scientists have located 55 seismic events in the vicinity, and say there may be well over 100 earthquakes linked to the swarm so far (shown above). The activity falls in line with magma recharge thought to be underway since 2008

In the last 30 days, scientists have located 55 seismic events in the vicinity, and say there may be well over 100 earthquakes linked to the swarm so far (shown above). The activity falls in line with magma recharge thought to be underway since 2008

In the last 30 days, scientists have located 55 seismic events in the vicinity, and say there may be well over 100 earthquakes linked to the swarm so far (shown above). The activity falls in line with magma recharge thought to be underway since 2008

Washington’s notorious volcano is best known for its ‘cataclysmic’ 1980 eruption, which brought devastation and destruction that stretched on for miles, and visible ash fall nearly 1,000 miles away.

The event has come to be known as one of the ‘deadliest eruptions in US history’.

It reawakened in 2004, spewing steam and ash up to 10,000 feet into the air.

This activity continued until January 2008, and five months later, scientists concluded Mount St. Helens had gone to sleep.

THE ‘CATACLYSMIC’ ERUPTION OF MOUNT ST HELENS, 1980

On May 18, 1980, Mount St. Helens in southwest Washington erupted.

The cataclysmic event killed 57 people and blasted more than 1,300 feet off the top of the mountain.

The eruption was trigged by a magnitude 5+ earthquake, which was accompanied by a debris avalanche.

This abruptly removed the pressure at the top of the volcano, allowing hot water to quickly become steam, expanding ‘explosively,’ according to USGS.

On May 18, 1980, Mount St. Helens in southwest Washington erupted. The cataclysmic event killed 57 people and blasted more than 1,300 feet off the top of the mountain. The aftermath can be seen above

On May 18, 1980, Mount St. Helens in southwest Washington erupted. The cataclysmic event killed 57 people and blasted more than 1,300 feet off the top of the mountain. The aftermath can be seen above

On May 18, 1980, Mount St. Helens in southwest Washington erupted. The cataclysmic event killed 57 people and blasted more than 1,300 feet off the top of the mountain. The aftermath can be seen above

A wave of decreasing pressure travelled down the volcano to the magma reservoir lying below.

The magma then began to rise and bubble, creating a massive eruption which lasted for nine hours.

The debris avalanche travelled westward as far as 14 miles down the North Fork Toutle River valley, with a total volume equal to 1 million Olympic swimming pools.

And, the lateral blast devastated the surrounding area nearly 19 miles west to east, and 12.5 miles to the north.

Pictured, photographers record ash one week following the eruption at Mount St Helens

Pictured, photographers record ash one week following the eruption at Mount St Helens

A woman shows the ashes left behind by the deadly 1980 eruption

A woman shows the ashes left behind by the deadly 1980 eruption

The eruption was trigged by a magnitude 5+ earthquake, which was accompanied by a debris avalanche. Scenes from the aftermath are pictured

In less than 15 minutes after the blast of hot material began, an eruption cloud had reached a height of more than 15 miles.

Roughly 520 million tons of ash were blown across the United States, causing complete darkness in Spokane, Washington – 250 miles away from the volcano.

The cloud circled the Earth in 15 days.

The earthquakes detected this year at Mount St Helens are thought to be tied to the recharge in the magmatic system, which was first detected in 2008.

And, the activity mirrors swarms that occurred this past November and almost exactly a year ago in March-May, which brought low-magnitude earthquakes at a rate of about 1-2 quakes per hour.

Still, the researchers say the current activity does not indicate that the volcano is readying for another deadly eruption anytime soon.

Mount St. Helens is located in Skamania County, Washington. Roughly 520 million tons of ash were blown across the United States when it erupted in 1980, causing complete darkness in Spokane, Washington – 250 miles away from the volcano

Mount St. Helens is located in Skamania County, Washington. Roughly 520 million tons of ash were blown across the United States when it erupted in 1980, causing complete darkness in Spokane, Washington – 250 miles away from the volcano

Mount St. Helens is located in Skamania County, Washington. Roughly 520 million tons of ash were blown across the United States when it erupted in 1980, causing complete darkness in Spokane, Washington – 250 miles away from the volcano

‘There are several reasons why it is very unlikely that this swarm is a precursor to imminent eruptive activity at Mount St. Helens – it is similar to the ones in the past that did not lead to surface activity,’ the USGS explains.

‘It consists of very small earthquakes occurring at relatively low rates; there are no other geophysical indicators (deformation, tilt, gas) of unrest.’

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