The University of Kobe confirmed that the Kikai caldera, located south of the island of Kyūshū, is accumulating new magma in its volcanic reservoir. The study, published in Communications Earth & Environment, reveals that this supervolcano —responsible for the most powerful eruption of the Holocene about 7,300 years ago— is in an active process of recharging.
The seismic and chemical analyses demonstrated that the present magma is more recent than that expelled in the Akahoya eruption, indicating a continuous injection of fresh material at depths between 2.5 and 6 km.
Importance of the magmatic system
The Kikai supervolcano is considered one of the most dangerous on the planet. Its study provides key information:
- Active recharge: confirms that the system is not inactive and evolves after the great Holocene eruption.
- Natural laboratory: allows understanding how the magma chambers of supervolcanoes fill, improving eruption prediction in systems like Yellowstone (USA) or Toba (Indonesia).
- Volume of magma: the mapped reservoir is massive and shows a continuous injection from deep sources.
- Geological evolution: evidence that giant calderas can reuse the same surface chamber in multiple eruptive cycles over millennia.
Potential risks
Although the recharge does not imply an immediate eruption, scientists warn of possible risk scenarios:
- Large-scale eruption (VEI-7): similar to Akahoya, which expelled more than 130 km³ of material.
- Devastating tsunamis: due to its underwater location, an eruption could affect the coasts of Japan, Korea, and China.
- Pyroclastic flows: capable of reaching more than 150 km away, with catastrophic consequences.
- Global climatic impact: the release of ashes and aerosols would alter regional and international climate.
- Minor eruptions: the lava dome on Satsuma Iwo-jima island maintains constant activity with ash emissions.
Historical and scientific context
The last major eruption of Kikai, known as Akahoya, occurred about 7,300 years ago and is considered the most powerful of the Holocene. It expelled more than 130 km³ of material, altering the climate and devastating large areas of the Japanese archipelago.
Today, constant monitoring through seismic waves and geochemical analyses allows for a better understanding of the volcano’s internal dynamics and anticipation of risks. For specialists, studying Kikai is essential for designing prevention and safety strategies in a densely populated region.
The Kikai supervolcano reminds us that large-scale geological systems remain active for millennia. Although there are no signs of an imminent eruption, its magmatic recharge is a scientific and regional alert: any future event would have devastating consequences for Japan and a global impact on the climate.
