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Why was Tonga's volcanic eruption so severe, and what could we anticipate next?

The Long Valley supervolcano eruption presents a 'existential threat' to millions of people in the United States.

THE LONG VALLEY CALDERA supervolcano is regarded as one of the most hazardous in the world, with its eruption posing an "existential threat" to millions of people in the United States.

The caldera is located in eastern California, near Mammoth Mountain. It is a gigantic, cauldron-like hollow that arises following an eruption and is one of the planet's biggest depressions. It is up to 3,000 feet deep and is a whopping 20 miles long and 11 miles long.

Bishop Tuff — a welded rock formation that characterises the region — was produced 760,000 years ago when a cataclysmic eruption unleashed plumes of hot ash that subsequently cooled and formed what is now known as the Bishop Tuff.


The incident sent ash eight miles into the sky, with deposits estimated to have landed as far east as Kansas – some 1,538 miles distant.

If Long Valley erupted again, the results would be catastrophic.

Despite this, it receives minimal attention in comparison to other volcanic sites like Yellowstone.

Long Valley may be on the verge of exploding, according to the Science Channel, whose recent volcanic activity was featured in the channel's 2017 programme 'Secrets of the Underground.'

There are worrying signals of volcanic activity.

And there are hints pointing to an impending eruption spread throughout this valley — the location of North America's second greatest explosive volcanic eruption.

Even if a modern-day eruption is not of the same magnitude as prior occurrences, it still poses an "existential threat" to the millions of people who live nearby.

A study in a section of the valley discovered many instances of smoke spewing out from beneath the earth.

InSAR is a remote sensing method that concentrates a beam of radiation on a target, which then bounces back to a sensor on an antenna, providing a precise map of a region.

One of the most concerning regions identified by the research was near Mammoth Lakes, a hamlet in the Sierra Nevada highlands.

On the screen, a strong red blob can be seen directly beneath the earth, where lava is most likely to be deposited.

Something beneath it is pulling it up.

The effort was made to create a pair of sensors and position them exactly above the resurrected dome, with the pipes assisting in detecting any changes in the Earth's magnetic field.

As a result, the scientists were able to assess whether any liquid – hot magma — was boiling away underneath.

The studies proved that there was a vast volume of liquid beneath the domes' surface, indicating that there was volcanic activity.

However, because the activity was decentralised, there was no cause for alarm.

A conclusion found that there is no massive magma chamber beneath. However, there are smaller satellite ones in the neighbourhood."

However, the possibility of an eruption has not been fully eliminated.

A year later, in 2018, evidence of ground deformation in Long Valley was discovered in a research published in the science journal GeoScience World.

The study's lead geologists discovered "ongoing uplift indicating fresh magma may have intruded into the reservoir" since at least 1978.

The uplift might be caused by molten rock flowing beneath the earth or by crystallisation of material deep beneath the ground.

Despite 40 years of research, the occurrence of enormous amounts of melt in Long Valley's magma reservoir remains a mystery.

According to the experts, the Long Valley Caldera reservoir holds "significant melt characteristics," perhaps more than 240 cubic miles (1,000 cubic kilometres).

Around 27% of this melt might be scorching liquid rock.

Long Valley last erupted around 100,000 years ago, according to the United States Geological Survey (USGS).


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