10 times the power of Baekdu Mountain's millennium eruption. The monster volcano 'Kikai Caldera' under the sea of Japan. It could cover the entire Korean Peninsula. | Professor Kim Ki-beom, Department of Geology, Pusan National University

Summary

Geology professor Kim Ki-beom explains the structure and risk of the Kikai Caldera, a massive submarine volcano off Japan's Kyushu coast. He details the volcanic cycle, the enormous magma chamber beneath it, and the potential for a VEI 7-8 eruption that could blanket Korea with ash. The discussion covers historical precedents, mechanisms of magma generation, and the specific threats to Korean agriculture, power grids, and aquaculture.

• The Kikai Caldera contains 220 km³ of magma, enough for a VEI 7-8 eruption far larger than Baekdu Mountain's millennium eruption.
• The caldera has rebuilt itself since its last eruption 7,300 years ago and is now at a mature stage in its volcanic cycle.
• Past eruptions from Japanese calderas (e.g., Aira, Kikai) have deposited ash across the entire Korean Peninsula, as evidenced by sediment layers.
• Ashfall from such an eruption would destroy crops, short-circuit high-voltage power lines, disrupt electric trains, and kill marine life through floating pumice.
• The professor distinguishes between frequent small eruptions (like Sakurajima) that relieve pressure and rare caldera-forming mega-eruptions.
• Magma generation is driven by decompression melting and water influx at subduction zones, not direct heating.
• The Nankai Trough region is seismically active and could trigger volcanic eruptions through earthquake-induced gas exsolution.
• Japan's Fuji eruption planning assumes 27 million evacuees, but Kikai's potential is 100 times more powerful.