Magma accumulating again beneath Japan’s supervolcano

An international team of researchers has discovered that the magma chamber beneath the Kikai Caldera in Japan is refilling, according to a study published in Communications Earth (ComEarth).

The Kikai Caldera formed around 7,300 years ago during one of the most powerful Holocene eruptions. To assess its current state, scientists conducted an underwater seismic survey using acoustic equipment and seafloor seismometers.

Analysis revealed a large magma-rich zone. Its chemical composition differs from the material ejected in the ancient eruption, indicating the influx of fresh molten rock from deep within the Earth. Further evidence comes from a lava dome forming in the caldera’s centre over the past 3,900 years.

“We must understand how such large quantities of magma can accumulate to understand how giant caldera eruptions occur,” said geophysicist Seama Nobukazu.

Researchers believe similar processes occur beneath other supervolcanoes, including Yellowstone and Toba, meaning these systems could become active again in the future. The findings will help improve eruption forecasting and monitoring of key volcanic reservoir activity.