About 7,300 years ago, a volcano under the sea erupted near Japan. It caused huge waves and covered the land in ash. Many people died. People in Japan hunted animals and collected wild food then.
A new study shows different changes across Japan. In southern Kyushu, the number of people fell before the eruption and dropped further afterwards. But northern Kyushu continued to grow. People from the south may have moved north. The sea near the northern coast recovered quickly and offered food.
Some places far from the volcano also stopped growing or lost people. The eruption did not destroy every community. Some people found new ways to live after the disaster.
