Mount St Helens warning: Molten rock rising
Scientists are now closely watching the volcano to make sure they are prepared in case the same happens again.
Amazon Prime’s “Mega Disaster: It’s Happened Before, It Will Happen Again” series revealed how a team of volcanists monitor the ticking time bomb.
Rick LaHusen, from the United States Geological Survey (USGS), detailed how they use an instrument known as the “Spider” to keep an eye on volcanic activity.
He said in 2006: “It’s a stainless steel superstructure that looks like a daddy-long-legs.
“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.”
However, Dr LaHusen’s analysis of the data provided a chilling revelation.
He added: “What is really phenomenal is how much rock is still coming out of the ground.