A volcano that caused the most destruction in US history has began rumbling again.
In May 1980, people sat in open fields and rooftops as rumours spread of an upcoming volcanic eruption.
Small earthquakes were recorded at the site just before the deadly eruption.
Advert
Then, at 8.32 am, the volcano erupted with a magnitude-5 earthquake.
The event was catastrophic. It blew off the volcano’s top, sending a super-heated mix of ash, rock fragments, and gas rushing down its slopes.
Those in the area had nowhere to take cover.
The sky turned dark as ash clouded the atmosphere, and destructive mudflows swept away homes, trucks, and anything else in their path.
Advert
The total avalanche volume equalled the volume of one million Olympic-sized swimming pools.
Now, more than four decades later, the volcano is showing signs of activity again.
Since February 1, 2024, approximately 350 earthquakes have been recorded by the Pacific Northwest Seismic Network.
Advert
95% of these have been less than magnitude 1.0 and are too small to be felt at the surface.
The largest recent quake with a magnitude of 2.0 was recorded on May 31, 2024.
In early June, the number of earthquakes recorded per week reached a peak of 38 events per week, mostly occurring around 4.6 miles below the crater floor.
Of course, people are now fearing that these earthquakes could lead to another massive explosion similar to the 1980s catastrophe that claimed 57 lives and permanently altered the area's ecosystem.
Advert
However, the good news is that the experts are not too concerned.
Similar sequences with even more quakes have happened in the past (1988-1992, 1995-1996, and 1997-1999) without triggering eruptions.
Specialised equipment has detected magma flowing through chambers deep underground, indicating that the volcano is recharging.
Advert
'Short-term increases in earthquake rates are common at Mount St. Helens and are considered part of background seismicity,' said experts at the Cascades Volcano Observatory.
'The last two periods of elevated seismicity (in 2023 and 2024) represent the largest short-term increase in earthquake rates since the last eruption ended in 2008.'
According to the scientists, the quakes are likely caused by pressurisation of the magma transport system, due to new magma entering - a process called 'recharging.'
They continued: 'Magma slowly rises through the lower crust and accumulates in a reservoir about 2.5 to 6 miles (4‒10 km) below sea level.
'Recharge events can occur when magma enters this upper reservoir and increases stresses that lead to earthquakes.'