Kagoshima caldera took 9,000 years to form magma for ancient eruption

A Japanese team said Thursday that it took an estimated 9,000 years for a massive magma chamber to form below the undersea Kikai Caldera in Kagoshima Prefecture before its catastrophic eruption 7,300 years ago.

The team of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and Kobe University analyzed sediments from the eruption extracted from a seabed near the huge caldera, located north of the island of Yakushima, using the deep-sea scientific research vessel Chikyu.

In the eruption, which occurred during Japan's Jomon prehistoric period, pyroclastic flows, or currents of hot gas and volcanic matter, reached Kagoshima's Osumi and Satsuma peninsulas at the southern tip of Kyushu, while volcanic ash traveled all the way to the Tohoku region.