Geologist Yoon Seong-hyo from Pusan National University who has been monitoring Mount Baegdu, a massive stratovolcano located on the border of North Korea and China, said on Sunday, April 12, 2015 ​the volcano is on the verge of erupting.

Mount Baegdu is relatively unknown volcano responsible for one of the largest known eruptions in history.

This eruption took place about 940 CE (VEI 7) and is known as the "millennium eruption" that deposited rhyolitic and trachytic tephra as far away as northern Japan. Measurements of ash deposits in Japan indicate that this was one of the two largest known volcanic eruptions on Earth since that period. It was matched only by the Tambora eruption in Indonesia, in 1815 AD.

This volcano is known as Tianchi or Changbaishan in China and Hakuto-san in Japan. Its Korean names are Baegdu and P'aektu-san.

Mount Baegdu in the Changbai Mountains along the border of China and North Korea in Northeast Asia - April 2003. Image credit: NASA.

Professor Yoon, who has been monitoring the volcano with an electronic distance measurement device (EDM), said the height of caldera has risen 1 cm since July 2014.

"The mountain's height has risen about 10 cm between 2002 and 2005," Yoon added. "It then began to sink in 2009. The shift changed only recently, which is significant." (KoreaTimes)

The temerature from the caldera's geyser had been around 70 °C, but recently rose to 83 °C. The helium concentration rate had also recently jumped from 6.5 times that of the normal atmosphere from 2002 - 2005 to seven times.

"All these signs indicate the magma inside the mountain is moving upward," Yoon said and called for close monitoring.

Lake Tianchi (Sky Lake) occupies the 5-km-wide, 850-m-deep summit caldera of Mount Baekdu. Image credit: Xiang Liu, 1983 (Changchun University).

Geologic summary

Massive Changbaishan stratovolcano, also known as Baitoushan and by the Korean names of Baegdu or P'aektu-san, is a relatively poorly known, but volcanologically significant volcano straddling the China/Korea border.

A 5-km-wide, 850-m-deep summit caldera is filled by scenic Lake Tianchi (Sky Lake). A large Korean-speaking population resides near the volcano on both sides of the border. The 60-km-diameter dominantly trachytic and rhyolitic volcano was constructed over the Changbaishan (Laoheidingzi) shield volcano.

Satellitic cinder cones are aligned along a NNE trend.

One of the world's largest known Holocene explosive eruptions took place here about 1000 CE, depositing rhyolitic and trachytic tephra as far away as northern Japan and forming in part the present caldera. Minor historical eruptions have been recorded since the 15th century. (GVP)

Featured image: Mount Baekdu in April 2003. Credit: NASA