It's been more than 1,000 years since the last time Mount Paektu erupted– but that last eruption was one of the largest in recorded history. That 9,000-foot volcano, which straddles the border between North Korea and China, has been waking up. And that volcano is responsible for bringing the North Korea and the Western world together for a surprising scientific collaboration.

Mount Paektu's infamous "Millennium eruption" occurred around 946 A.D., the Washington Post reports, and its destruction was legendary.

"It's hard really to imagine the scale, but you're talking about something like 1,000,000 nuclear weapons all going off at the same time in terms of the energy involved," British scientist Clive Oppenheimer told CBS News in 2014.

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A soldier overlooks the crater lake in Mount Paektu, which lies on the border between North Korea and China. (Getty/Raymond Cunningham)

The fear that this could happen again is what has North Korean officials in the midst of an unprecedented call for assistance. The volcano rumbled conspicuously in the early-to-mid 2000s.

Oppenheimer and another British scientist, John Hammond, were the two volcanologists chosen to study Mount Paektu alongside local scientists in 2011. They've been studying the volcano for several years, and their first round of research has finally been published in the journal Science Advances. It's thefirst study that has ever looked into the Earth's crust beneath North Korea.

"The results show that a large region of the crust has been modified by magmatism associated with volcanism and that partial melt is likely to be present throughout a significant portion of the crust," the researchers say in the study. "The region may represent a potential source for magmas erupted in the historical period and possibly associated with the episode of unrest that occurred between 2002 and 2005."

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That partially melted portion of the crust does not signify the impending threat of an eruption, but does call for further study.

“One of the challenges now is to go beyond simply saying there’s magma in the crust, discovering instead how it’s sitting, how much there is and what are the implications,” Hammond told New Scientist. “It’s only when it gets to a certain amount and a certain overpressure that it will erupt.”

Their further research into the volcano could last for as many as 10 years, he said.

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A man uses his shirt to cover his face as he walks through the ash-covered streets of San Andres Cholla, Mexico, Monday April 18, 2016, after the Popocatepetl volcano erupted overnight, spewing ash on nearby towns. Officials there are urging to people to wear masks to avoid inhaling the fine grit that has covered houses and cars. (AP/Pablo Spencer)