Survivors of Japan’s ancient volcanic catastrophe may have found a lifeline along the coast, where communities grew even as more distant populations faltered.
Around 7,300 years ago, the Kikai-Akahoya eruption damaged ecosystems and made parts of Japan uninhabitable for the Jomon people, who lived there by hunting and gathering. Yet some Jomon populations continued to grow through the disaster and its aftermath, while population growth stalled or reversed in more distant areas.
For decades, archaeologists have debated whether the eruption brought an “apocalypse” that abruptly ended all human life closest to its epicenter or whether local populations survived even relatively nearby. A new international study led by Lund University finds that neither total collapse nor simple continuity fully explains what happened.
“This eruption must have been devastating, exploding out of the sea bed with little warning. It battered the Japanese islands with powerful earthquakes and enormous tsunamis, and then blanketed the landscape with meters of volcanic ash,” explains senior author Peter Jordan, professor of archaeology at Lund University.
Northern Kyushu grew through the disaster
The researchers found that populations declined as ecosystems deteriorated and areas became uninhabitable. In southern Kyushu, however, Jomon populations had been shrinking long before the eruption. The disaster struck a region that was already sparsely populated and visited only by highly mobile groups.
Northern Kyushu had a different population history. Its population was growing before the eruption, and that trend continued through the disaster and its aftermath despite extensive, lasting ecosystem damage. The authors suggest that “refugees” moving out of the worst-hit areas immediately after the eruption may have helped sustain that growth.
Survivors from inland areas appear to have moved away and clustered along northern coastlines, where marine ecosystems recovered quickly. New ways of drawing on the sea’s abundant resources may also have accelerated population growth.
“The disaster caused major loss of life. However, survivors migrated, forged new social relations, innovated new kinds of economy, and appear to have found creative ways to exist and later thrive in the new post-disaster conditions,” says lead author Enrico Crema, professor at Cambridge University.
Population declines farther from the eruption
In more distant parts of Japan, populations that had been growing before the eruption stagnated or declined afterward. These far-reaching effects had not previously been identified. They may have been linked to short-term climate change triggered by the eruption or to extreme tooth wear in the deer and boar that Jomon communities relied on for food. The animals may have suffered that dental damage while grazing in ash-covered landscapes. Other volcanic effects on human health and well-being could also have contributed.
For Jordan, the contrasting outcomes demonstrate how complex and unpredictable the aftermath of a major disaster can be.
“This study helps in creating a deeper understanding of the contingent ways in which cultures and societies cope with sudden shocks and catastrophes. Even in the most impossible situations, survivors and communities have choices, however limited: they need to act and make decisions, they need to adjust, collaborate and find new connections and social networks,” he concludes.
Reference: “Divergent demographic responses to the Kikai-Akahoya volcanic catastrophe in mid-Holocene Japan” by Enrico R. Crema, Mitsuhiro Kuwahata, Junzo Uchiyama, Ari Junno, Felix Riede and Peter D. Jordan, 14 October 2026, Science Advances.
DOI: 10.1126/sciadv.aeh7197
This work was supported by the Swedish Research Council (grant no. 2024-00822) (P.D.J.), JSPS KAKENHI (grant nos. JP25K00523) (M.K.), and the European Research Council (grant no. 101224035) (E.R.C. and P.D.J.).
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