When the North Korean mountain erupted in 946, it was more powerful than the one that buried Pompeii
Straddling the border between China and North Korea, Mount Baekdu holds immense symbolic significance for the people on the Korean Peninsula -- so much so that it graces the lyrics of both Koreas' national anthems.
Revered as the mythical birthplace of the Korean people, the 2,744-meter-tall mountain is steeped in legends and myths. One of them even features a mysterious creature dwelling in Heaven Lake, the vast crater lake on the mountaintop, akin to the Scotland's legendary Loch Ness monster.
But perhaps the real monster isn't in the lake -- it's the mountain itself. Beneath its legendary peak lies a massive powder keg: An active volcano that some fear could unleash catastrophic destruction.
Sleeping giant
A doomsday scenario circulating primarily on social media -- and capturing the attention of some politicians here -- paints Mount Baekdu as building up power for a massive outburst in near future.
And when it does erupt, it will be the day South Korea, despite being outside the direct impact zone, grinds to a halt. Stocks will crash, massive power blackouts will shut down factories, and road and air traffic will be suspended. The air will become toxic, the scenario goes, and the climate will be altered for years, disrupting agricultural output.
Just last year, speculation ran wild that that day would come in 2025, a century after the last alleged eruption in 1925. It became such a hot topic that it even made its way into a parliamentary hearing in October last year, when a lawmaker grilled the Korea Meteorological Administration chief about the chances of an imminent eruption.
The KMO’s formal stance was that an eruption next year is unlikely, given the stable condition reported for Mount Baekdu.
To understand the source of Koreans' fears, one needs to look at the volcano’s fiery past.
According to scientists, Mount Baekdu first erupted around 5 million years ago, spewing lava flows that formed the foundation of the mountain we see today. It has erupted sporadically since then, with some blasts far more powerful than others.
The most dreadful eruption known to have occurred was in 946. Known as the "Millennium Eruption," it is considered one of the largest volcanic eruptions in the past 5,000 years, earning a Volcanic Explosivity Index rating of 6. To put that into perspective, the infamous eruption of Mount Vesuvius in AD 79 that buried the ancient city of Pompeii in volcanic ash was a VEI 5.
Volcanoes erupt when underground magma chambers fill with molten rock until the pressure becomes too great to contain. It can take centuries or even millennia for these chambers to refill after each eruption, which explains the irregular activity of many volcanoes.
The Korean weather agency’s website displays records of Mount Baekdu’s volcanic activity by century from the 900s to the 1900s, revealing that not a single century has passed without some notable activity, whether an eruption, rumbling, or smoke. In the 1900s, there were two events, in 1903 and 1925.
The Smithsonian Institution's Global Volcanism Program database lists only six potential eruptions of Mount Baekdu since 1413, with the latest research suggesting that just three events -- in 1413, 1668, and 1903 -- are considered likely to be actual eruptions based on available evidence. All of these were minor rumblings that caused little damage.
If anything, the data suggests that the magma chambers powering Mount Baekdu's mega-eruptions fill up at a much slower rate, likely taking millennia. Prior to the Millennium Eruption, the volcano's last mega-size outburst is thought to have occurred at least 4,000 years earlier and possibly up to 50,000 years ago.
One challenge in assessing the risks posed by Mount Baekdu has been the lack of access to information. With a big chunk of the mountain sitting in North Korean territory, South Korean scientists haven't had much chance to study it firsthand. Most data comes from the Chinese side, and the two countries haven't teamed up for many joint research projects.
Jeong Hyun-sook, the director of the KMA’s Earthquake and Volcano Bureau, said during last year’s parliamentary audit, “We are monitoring Mount Baekdu using satellites,” in addition to analyzing the Chinese data.
According to the official, seismic data collected by Chinese scientists since 1999 indicate that while Mount Baekdu experienced a flare-up in the early 2000s, it has generally been stable since 2006.
The what-ifs
Make no mistake, Mount Baekdu is an active volcano. While a massive eruption may be unlikely anytime soon, it's bound to happen eventually. So what might that look like?
A repeat of a mega-eruption, like the one that occurred in 946, would unleash deadly avalanches of hot gas and debris down the mountainside, decimating all life in the area with little warning. It's pyroclastic flows could reach as far as 100 kilometers away, putting cities like Samjiyon squarely in the danger zone.
The nearly 2 billion tons of water in its crater lake, which would come into contact with the lava, could exacerbate the situation, leading to deadly effects such as steam explosions, lahars, or volcanic tsunamis, ultimately making the eruption even more devastating.
South Korea is outside the direct impact zone, with Seoul located approximately 500 kilometers from Mount Baekdu.
If the eruption occurs when the region’s prevailing westerly winds are strong enough, typically during the winter months, most of the airborne ash will be blown toward the East Sea and Japan, just as it was during the Millennium Eruption.
Historical records also support this scenario. The History of Goryeo, an extensive chronicle of the Goryeo Dynasty compiled during the succeeding Joseon era, only briefly mentions “a thunderous sound across the sky" about the 946 event and says nothing about ashfall or other climate disruption. In contrast, Japanese sources from the time describe extensive snow-like ash.
Overall, despite its enormous scale, the climate impact of the Millennium Eruption is thought to have been relatively muted -- a puzzle that has long mystified scientists.
A new study published in October shed light on this mystery. A team of Seoul National University researchers, led by professor Ahn Jin-ho, found that the volcanic sulfur didn't reach high enough into the atmosphere to trigger severe global cooling, and that the sulfur compounds degraded faster compared to other major eruptions. Their analysis also revealed that the eruption unfolded in two phases over 1-2 months, potentially spreading out its effects.
Still, it's always better to be forewarned even if the risks seem remote, which is why experts continue to call for increased monitoring and cross-border research efforts to better understand this sleeping giant.
