About 7,300 years ago, the Kikai-Akahoya volcano erupted beneath the sea near Japan. Powerful earthquakes, enormous waves, and thick layers of ash devastated communities. An international research team led by Lund University studied how populations changed after the disaster. The findings challenge the idea that communities either disappeared completely or remained largely unaffected.
In southern Kyushu, the population had already been falling before the eruption, which made an existing decline worse. Northern Kyushu followed a different pattern: its population continued growing despite serious environmental damage. Researchers suggest that people escaping southern areas may have moved north. Some inland survivors may also have moved toward the northern coast, where sea life recovered more quickly and provided food.
The effects reached beyond the areas closest to the volcano. Some distant communities that had been growing stopped growing or lost people afterward. Possible explanations include changes in climate, ash damage to food supplies, and health problems. Rather than showing a single pattern of collapse, the study reveals regional losses, continued growth, and possible movement between communities.
