Mount St Helens ‘BACK to life’: How scientists found magma RISING inside volcano
MOUNT St Helens came “back to life” following its devastating eruption almost 40 years ago, it was revealed during a documentary on natural disasters.
Mt St Helens: Scientists reveal volcano's 'extreme activity'
On May 18, 1980, Mount St Helens erupted in the US state of Washington. The event, which measured 5 on the Volcanic Explosively Index, has been declared the most disastrous in modern US history. A huge column of volcanic material rose 80,000ft into the atmosphere and deposited ash in 11 states, killing at least 57 people and causing more than $1billion (£770million) in damage.
However, National Geographic series “Back from the Dead” revealed how Mount St Helens became a concern again after it "suddenly came back to life".
The documentary interviewed Daniel Dzurisin, a leading scientist with the United States Geological Survey, who revealed how his team encountered a scare two years after the eruption.
He said in 2017: “We noticed a crack that had not been there before.
“By the end of the day it was larger – you would realise the ground was moving beneath your feet.
We didn’t know what might come next, whether the lava would continue to grow for several years, or even decades or centuries
“If you stood and looked carefully with a reference point in the background, you could see it move.”
Volcanoes typically erupt when molten rock, known as magma, pushes its way to the surface.
This act creates a series of small earthquakes, fracturing the rock above it, before the main event.
Mr Dzurisin went on to explain how the team set up a time-lapse camera, which showed a dome rising under the increasing pressure of magma below.
Mount St. Helens 'lave dome' rising five metres a day says expert
He continued: “We didn’t know what might come next, whether the lava would continue to grow for several years, or even decades or centuries.
“We didn’t know if there would be explosive eruptions either.
“There was still a tremendous amount of noise.
“Rock falls were constant and 2,000ft above your head you could see where the summit of the volcano used to be.
“We were standing in a crater with a lava dome steaming – it was very exciting.”
It was previously revealed how scientists are now using an instrument known as a “Spider” to keep an eye on any change in activity.
Rick LaHusen, also from the USGS, said in 2016: “We needed a way to get our instruments up there quickly without putting people at risk.
“So we built this stainless steel superstructure that looks like a daddy-long-legs and lets us locate exactly where the signals are.
“This is a GPS antenna which receives timing signals from satellites and lets us locate exactly what is going on inside.
“The signals go into the computer system and then the data comes out at the request from computers back in the office.”