The 946 eruption of Paektu Mountain, a stratovolcano on the border of North Korea and China also known as Changbaishan,[1] occurred in late 946 CE.

Therefore, the timing of this eruption was one of the most intensely studied subject in the volcanology of Paektu Mountain, before its final settlement in the late 946 CE.

Further constraints on the date were obtained when the major 774-775 CE carbon-14 spike (Miyake event) was identified in one of the tree stumps felled by the eruption.

The comenditic and trachytic volcanic glass shards with chemical fingerprints associated with the Millennium eruption were located in the Greenland ice core, and the position corresponds to a date of 946–947 CE.

Another similar but later record from the Goryeosa (History of Goryeo) describes, at the palace in Kaesŏng, of a loud disturbance: In the first year of the reign of Emperor Jeongjong (946 CE), heaven's drums sounded.

In addition, the Heungboksa Temple History (Annals of Kōfukuji) recorded a particularly interesting observation in Nara, Japan:[11] On 3 November 946 CE, evening, white ash fell gently like snow.

[10][14] The first phase began with a Plinian eruption that produced widely dispersed comenditic tephra followed by unwelded pyroclastic flows and surges.

After a hiatus of unknown duration, the second phase produced trachytic agglutinates and welded pyroclastic flow and surge deposits.

The first phase began with a stable Plinian eruption column which was estimated to have reached a height of 30–40 km[7] and produced a widely dispersed layer of light coloured pumice fallout.

[7] Based on the historical records of falling white ash in Nara, it is suggested that the first phase may have started on 2 November 946 CE.

Bodies of magma often become trapped in the crystals during crystallisation forming melt inclusions, which are analysed to determine the original volatile concentration.

The remaining amount of the volatile dissolved in the melt is established by analysing the matrix glass – the magma quenched on eruption.

[7] The fluorine and chlorine contents of MI and matrix glasses cover a similar range, suggesting the melts were probably not saturated in either element, and loss of these volatile phases could be negligible.