VOLCANO ALERTS: You want to talk 'catastrophic climate change'?

Yellowstone Caldera

At least two potential super-volcanos have the attention of scientists worldwide because of the devastation any of them – two in the U.S. and one in Japan – could wreak on the planet, killing tens of millions and ravaging global economies.

Saturday's rumblings at the Yellowstone Caldera in America's most famous national park caught the attention of seismologists over the weekend because of its cataclysmic potential. Scientists warn that a major eruption of the Wyoming volcano would kill an estimated 87,000 people immediately and render two-thirds of the U.S. uninhabitable because of an ash cloud that would spark rapid climate change.

If that scenario sounds apocalyptically scary, consider the other volcano being watched worldwide off the shore of Japan. Just last week, Japanese scientists were warning an eruption at the Kikai Caldera, about 50 miles south of Japan's main island, could kill 100 million people and set off catastrophic global climate change that would make the world forget about "global warming" scares.

Kikai Caldera

The Japanese lava dome was recently discovered in an underwater volcano. It is growing in size and was formed, scientists believe, following what is known as the Akahoya super-eruption that may have wiped out the ancient Jomon culture that inhabited the southern Japanese island of Kyushu at the time.

"Although the probability of a gigantic caldera eruption hitting the Japanese archipelago is 1 percent in the next 100 years, it is estimated that the death toll could rise to approximately 100 million in the worst-case scenario," said professor Yoshiyuki Tatsumi, head of the Kobe Ocean-Bottom Exploration Center and a magma specialist.

Super-eruptions are rare but devastating events that can have global impacts due to volcanic ash and chemicals obscuring the sun and triggering a "volcanic winters."

Researchers who made the discovery said there was a slim chance a super-eruption could occur at the site, releasing over 10 cubic miles of magma in one burst.

On a series of three survey voyages conducted last year Tatsumi and his team explored the bottom of Kikai Caldera, a crater that forms when a volcano collapses following eruption. The lava dome rises 600 meters above the seabed.

Lava is magma that has reached the surface when a volcano erupts. Magma is molten rock below the earth's crust. Analysis of rocks from the dome revealed it was formed by solidifying lava – the result of a far smaller eruption that has taken place since Akahoya.

The results of this research were published in the journal Scientific Reports, and Tatsumi is planning another voyage to the site next month to confirm the findings. The team plans to use underwater robots to unravel the processes that resulted in the volcano's formation and use seismic and electromagnetic methods to determine the existence of a sizeable accumulation of magma.

Meanwhile, in Yellowstone, scientists say a massive eruption could be 6,000 times more powerful that Washington state's Mount St. Helens in 1980, which killed 57 people an deposited ash in 11 different states and five Canadian provinces.

If the volcano explodes, a climate shift could ensue as the volcano would spew massive amounts of sulphur dioxide into the atmosphere, which can form a sulphur aerosol that reflects and absorbs sunlight.

If all that is not enough to worry about, there are three more volcanos in California alone that are have threat levels listed as "very high" – Mount Shasta, Lassen Volcanic Center and Long Valley Volcanic Region. Three more are listed at "high threat" levels – Clear Lake Volcanic Field, Medicine Lake Volcano and Salton Buttes.

In 2005, a national team led by John Ewert, a volcanologist with the U.S. Geological Survey's Cascades Volcano Observatory, established a system for deciding which of the United States' 169 young volcanoes are the most dangerous and most in need of monitoring. In the "Framework for a National Volcano Early Warning System," Ewert's team identified 57 priority volcanoes in the U.S.