A lava dome discovered in the Pacific Ocean off southern Japan contains more than 7.5 cubic miles of volcanic magma and could kill as many as 100 million people if it erupts, according to Japanese scientists.. Researchers at the Kobe Ocean Bottom Exploration Centre reported that the lava dome – one of the largest ever discovered in the world – is expanding within the Kikai Caldera, an undersea volcano just over 30 miles from the southern tip of Kyushu, the most southerly of Japan’s main islands.
The dome stands nearly 2,000 feet proud of the seabed and is now a mere 100 feet beneath the surface. It is more than six miles in diameter and occupies a massive hollow within the caldera..
Distortions in the surface of the feature have led researchers to conclude that lava is building up beneath the dome, a suspicion heightened by plumes of superheated water and bubbling around the caldera..
There’s an Absolutely Massive Lava Dome Lurking Underneath Japan – Here’s what that means
An ancient underwater volcano responsible for one of the largest known super-eruptions in history looks to be busy making silent, fiery preparations for its inevitable return.
The Kikai Caldera.. devastated a large swathe of the Japanese archipelago when it spewed upwards of 120 cubic miles of magma during the Akahoya eruption some 7,000 years ago – and scientists have just confirmed evidence of new volcanic activity under the crater..
“The lava dome is chemically different from the super-eruption, suggesting that a new magma supply system had been developed after 7,300 years ago,” In other words, whatever the significance of the lava dome is, this volume of hot, viscous rock – standing some 1,968 feet tall.. isn’t an echo of Akahoya, but something new taking shape under the East China Sea.