The 946 eruption of Paektu Mountain, on the boundaries of China/Korea, was one of the most powerful in recorded history and is classified as a VEI-7 event. The eruption resulted in a brief period of significant climate change in China. The age of eruption has not been well constrained, but a possible date is A.D. 946. The 946 eruption of Paektu Mountain has been dubbed the "Millennium eruption" or the "Tianchi eruption", and erupted about 100–120 km3 (24 to 28.8 cubic miles) tephra. The eruption began with a strong Plinian column, and ended with voluminous pyroclastic flows. An average of 5 cm of Plinian ashfall and coignimbrite ashfall covered about 1.5 million km2 of the Sea of Japan and northern Japan. This ash layer has been named the "Baegdusan-Tomakomai ash"(B-Tm). It probably occurr