This is fascinating.
A giant lava bubble is expanding at Kikai volcano, a supervolcano just 31 miles south of Japan’s main island of Kyushu.
More than 31 cubic kilometers (7.4 cubic miles) of lava have shoved the seabed up around 2,000 feet, creating a giant dome with a diameter of about six miles.
The rising dome, with its peak is now less than 100 feet (30 m) below the ocean’s surface, is estimated to contain a much more immense volume of lava than theYellowstone or Long Valley calderas.
The area also contains active hydrothermal springs and dense streams of gas bubbling up from the sea bed.
“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 new study published inNature Scientific Reports.
Dr. Tatsumi thinks the chances of a supereruption in thewithin the next 100 years are only about 1 percent. But when that eruption comes, it could eject nearly 10 cubic miles of magma, enough to cover almost all of Japan in ash nearly eight inches thick, he found.
Researchers say such an eruption could kill some 100 million people who live within its fallout zone, which includes the cities of Nagasaki, Hiroshima and Osaka.
Such an eruption would also have a serious effect on global climate. Temperatures would plunge and crops would fail.
Kikai has exploded catastrophically before. Japanese volcanologists have found evidence of an eruption of 500 cubic kilometres (120 cubic miles!) of magma some 7,300 years ago (the Akahoya eruption), another about 95,000 years ago, and yet another about 140,000 years ago.
Via Robert