The massive Yellowstone supervolcano, whose eruption might one day end all life on Earth, isn’t overdue for its next “scheduled” eruption but it will definitely explode with a violence not seen in 640,000 years.

And when it does, humans will be among the first species to go extinct during the planet-killing Armageddon.

There still is speculation this seething supervolcano at the Yellowstone National Park in Wyoming is mathematically overdue for another horrific eruption that will render most of the United States uninhabitable.

The Yellowstone supervolcano is the world's largest and most dangerous volcano. Its caldera spans 40 km x 60 km (25 miles x 37 miles) and was formed after its last cataclysmic eruption 640,000 years ago. Its two other monstrous eruptions occurred two million and 1.3 million years ago.

The United States Geological Survey (USGS) estimates the chance of Yellowstone exploding in the coming centuries is very low. It’s a view shared by Dr. Jamie Farrell, Assistant Research Professor, Department of Geology and Geophysics at the University of Utah.

Dr. Farrell led a team back in 2013 that made the frightening discovery, the size of the huge magma reservoir below the caldera far exceeded previous estimates.

"We found it (the magma reservoir) to be about two-and-a-half times larger than we thought,” said Dr. Farrell. "That's not to say it's getting any bigger, it’s just that our ability to see it is getting better.

A realist, Dr. Farrell knows Yellowstone must again erupt but it likely won’t be within this century.

"We believe it will erupt again someday, but we have no idea when,” he pointed out. “What we're seeing now agrees with the geological data that we have about past eruptions. And that means there's the potential for the same type of eruption that we've seen in the past."

He knows some people say the Yellowstone volcano is overdue to erupt, but there's no evidence it’s overdue.

“We can't say when the next eruption is going to happen,” he pointed out. “However, I think we'll have anywhere from weeks to months of warning that magma is moving up into the shallow crust and (that) something is going on.”

When Yellowstone does erupt, it will hurl more than 240 cubic miles of magma across Montana, Idaho, and Wyoming. The eruption will also trigger catastrophic climate effects worldwide.

The supervolcano will erupt lava into the sky for thousands of feet and dump a layer of volcanic ash 10 feet deep up to 1,000 miles away. Most of the U.S. will be covered by a thick layer of ash that will kill almost all plant life. Scientists estimate two-thirds of the U.S. will become immediately uninhabitable

Some experts believe the next Yellowstone eruption will be a planet-killing cataclysm that will wipe-out practically all life on Earth.

Tourists Watch Old faithful in Yellowstone National Park
Tourists Watch Old faithful in Yellowstone National Park. Wikimedia Commons