Researchers at Kobe University say a large magma reservoir beneath Japan’s Kikai caldera appears to be filling again with new molten material, according to ScienceDaily.
Kikai is a mostly submerged volcano south of Japan that produced the largest known eruption of the Holocene about 7,300 years ago. That eruption emptied so much magma that the ground above the reservoir collapsed, forming the caldera now seen there.
To study the underground system, the team worked with the Japan Agency for Marine-Earth Science and Technology and used seismic surveys across the caldera. Their results, published in Communications Earth & Environment, showed a magma-rich zone beneath the part of Kikai linked to the ancient eruption.
According to Kobe University geophysicist Nobukazu Seama, the size and location of the reservoir suggest it is the same system that fed the earlier giant eruption. But chemical evidence from a lava dome that has been growing for about 3,900 years indicates the current magma supply is newer than the magma released long ago.
The researchers say the findings support a model in which fresh magma gradually re-enters and rebuilds reservoirs beneath giant calderas after major eruptions. They note the work could help scientists better understand other large caldera systems, including Yellowstone and Toba, but they stress the discovery does not mean Kikai is about to erupt.
