About 7,300 years ago, an undersea volcano off the coast of southern Japan blew apart with almost no warning, and the foragers of the Jomon period living nearby faced what Cambridge University Press describes as the largest volcanic eruption of the Holocene, the geological epoch that began after the last Ice Age. A new international study finds that their fates diverged sharply: populations fell where land became uninhabitable, yet grew in other places where survivors may have gone.
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The research, published Oct. 14, 2026 in the journal Science Advances and led from Lund University in Sweden, challenges two older and simpler pictures of the event, one in which the Jomon of the region were wiped out and one in which local communities mostly carried on as before.
Kikai-Akahoya and the Jomon foragers
The eruption is known as Kikai-Akahoya. Researchers at Kanazawa University describe it as the largest catastrophic eruption of the last 30,000 years of Earth’s history, and a newer 2024 study cited there indicates it was bigger than previously thought. A Cambridge University Press blog post on the research programme studying it adds that the event brought earthquakes, tsunamis reaching up to 30 meters, and pyroclastic flows that destroyed vegetation, and that a thick ash layer, a “disaster horizon,” remains visible across Kyushu, Japan’s southwesternmost main island.
Peter Jordan, professor of archaeology at Lund University and the senior author, said in the university’s release that the eruption “must have been devastating, exploding out of the sea bed with little warning”. Enrico Crema, the lead author and a professor at Cambridge University, put the human cost bluntly: “The disaster caused major loss of life.”
Where Jomon populations fell and where they grew
The study, titled “Divergent Demographic Responses to the Kikai-Akahoya Volcanic Catastrophe in Mid-Holocene Japan”, sorts the response into regions. In southern Kyushu, the closest area, Jomon populations were already declining before the eruption, and the landscape was sparsely populated and visited mainly by highly mobile groups. Populations also declined in areas where ecosystems suffered and land became uninhabitable.
Northern Kyushu told a different story. Population growth there continued through the disaster and its aftermath, despite lasting ecosystem damage. The authors suggest the increase may reflect refugees moving out of the worst-hit areas, which is why the evidence supports refugees only as a possibility rather than a documented migration. Crema said survivors migrated, formed new social relations and developed new economies.
Inland communities appear to have shifted toward the northern coastlines, where marine ecosystems recovered quickly. Growth in those places may have been driven by exploiting abundant marine resources. The study frames that coastal pull as the likely route by which inland survivors rebuilt their lives.
Farther away, the pattern reversed. In distant parts of Japan, populations had been growing before the eruption but stagnated or declined afterward. The release lists possible causes, including short-term climate change, tooth attrition in deer and boar from grazing on ash-covered land, and other volcanic impacts on health. The finding means that even places far from the blast could feel its effects, whatever the mechanism turned out to be.
Earlier evidence from Tanegashima and the CALDERA programme
The new study builds on a body of field research. According to the Cambridge blog, early Japanese archaeologists proposed an apocalypse model in which Jomon foragers abruptly collapsed and Kyushu became a long-term cultural wasteland. Pottery research by Mitsuhiro Kuwahata and colleagues suggests small populations survived in protected pockets near the epicenter, and other work indicates large Jomon villages had already disappeared centuries before the eruption, with communities cycling between settled villages and more mobile ways of life in step with climate shifts such as the 8.2 kiloyear cooling interval. That background matters because it shows the region was not a thriving, densely settled landscape that vanished overnight, and it fits the new finding that southern Kyushu was already in decline.
On Tanegashima Island, the eruption killed people, and the island was resettled from the mainland only after several centuries, with the newcomers changing their subsistence strategies because of lasting ecosystem damage; two of the sites studied there are Ichijin-Nagasakibana, dated to roughly 6900 to 6500 calibrated years before present, and Sankakuyama. Junzo Uchiyama of Kanazawa University and Jordan lead a Nordic-Japanese research programme called CALDERA, which won the Antiquity journal’s Ben Cullen Prize in 2024 for its pilot study of human responses to the eruption.
Jordan said the findings deepen understanding of how societies cope with sudden shocks and catastrophes. For archaeologists, the lesson is that a single disaster can produce collapse, survival and growth at once, depending on distance, ecology and the choices of the people involved, a pattern the authors summarize in the name of their study as divergent rather than uniform. The result also gives researchers a template for reading other prehistoric catastrophes, where the temptation is to assume a single outcome for everyone in the region. Careful regional comparison of population trends can show who lost, who gained and who simply moved on.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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