Some 7,300 years ago, a supereruption devastated the southern islands of what is now Japan, burying most of the archipelago in thick ash. Known as the Akahoya eruption, the blast was so powerful it caused the volcano’s magma chamber to collapse, leaving a 12-mile wide scar called Kikai Caldera, which is mostly underwater.
Now in a study published Friday, scientists have discovered that a dome of lava lurks beneath the caldera. By studying its magma plumbing, volcanologists could gain insight into the entire caldera system, which could help them better predict when another eruption in the Japanese archipelago might occur.
“The most serious problem that we are worrying about is not an eruption of this lava dome, but the occurrence of the next supereruption,” said Yoshiyuki Tatsumi a volcanologist at Kobe University in Japan and lead author of the study that appeared in the journal Scientific Reports.
Dr. Tatsumi’s previous work has suggested that the chances of a supereruption happening in the Japanese archipelago in the next century are only about 1 percent. But if a volcano in this area erupts, it could eject nearly 10 cubic miles of magma, covering almost all of the country and its 120 million people in nearly eight inches of thick ash, he found.