Date of ancient volcanic eruption finally pinpointed using fossilised tree rings

The Changbaishan eruption, one of the most violent of the last two millennnia, has been dated to within three months of the winter of 946 AD

The fossilised remains of a tree killed more than 1,000 years ago when a volcano blew a four-kilometre-wide hole in the landscape, on the border between China and North Korea, have helped an international team of scientists date one of the most violent eruptions of the last two millennnia to within three months of the winter of 946 AD.

The date matches a vivid description in a chronicle from a temple in Japan, far from any of that country's active volcanoes, and 1,000 kilometres from the Changbaishan volcano. The monks recorded "white ash falling like snow" on 3 November 946AD. Another ancient record from 470km away, close enough to be within the sound of the eruption, said that in that year "the sky rumbled and cried out," and recorded that there was an amnesty - presumably because it was taken as a dire omen - which led to prisoners being freed.