The magma reservoir of the largest volcanic eruption of the Holocene is refilling. This Kobe University insight on the Kikai caldera in Japan allows us to understand giant caldera volcanoes like Yellowstone or Toba more generally and gets us closer to predicting their behavior, too.

Some volcanoes erupt so violently, ejecting more magma than could cover all of Central Park 12 km deep, that all that's left is just a wide and rather shallow crater, a so-called "caldera." Examples of such supervolcanoes are the Yellowstone caldera, the Toba caldera and the mostly underwater Kikai caldera in Japan, which last erupted 7,300 years ago in what was the largest volcano eruption in the current geological epoch, the Holocene.

It is known that these volcanoes can and do reerupt but very little is known about the processes that lead up to an eruption and are therefore ill-equipped to make predictions.

"We must understand how such large quantities of magma can accumulate to understand how giant caldera eruptions occur," says Kobe University geophysicist Seama Nobukazu.