About 7,300 years ago, a volcano under the sea exploded near Japan. It caused huge waves and covered land with ash. Many people died. A new study shows different changes across Japan.
In southern Kyushu, the number of people fell. But this change started before the disaster. In northern Kyushu, the number kept growing. Some people may have moved north from the south. Life in the sea returned more quickly near the northern coast. People found food there.
Farther away, some areas also stopped growing or lost people. Ash, changes in the weather, or health problems may help explain this. The disaster did not affect every community in the same way.
