08-07-2025
Magma could further activate volcano in southwestern Japan
Experts in Japan have found that ash spewing from an erupting volcano in the country's southwest since last month contains an increasing volume of substances derived from fresh magma.
Authorities are urging people to beware of falling volcanic rocks and pyroclastic flows around the crater as magma may be building up.
Mount Shinmoedake in the Kirishima mountain range straddles the prefectures of Kagoshima and Miyazaki. It erupted on June 22 for the first time since 2018.
Eruptions are continuing. The volcano blew an ash plume over 5,000 meters above its crater. It is also releasing 2,100 to 4,000 tons of sulfur dioxide contained in volcanic gas per day.
Researchers in the National Institute of Advanced Industrial Science and Technology analyzed the ash from last Wednesday's eruption and detected several percent of substances that came from new magma. They said only a fraction of such substances were observed at the start of the eruption.
The Japan Meteorological Agency suggests that the recent trend could be driven by underground magma activity.
Usui Yuji, an analyst in the agency's volcanology department, said the recent events are not close to steam eruptions, but they cannot be called magma eruptions either. He said they appear to be something in-between.
He warned that if the volcano shifts to full-scale magma eruptions, large amounts of ash could be spewed and lava could flow down.
Usui said the agency has already specified an alert zone in the event of a magma eruption, and asked people to stay away from the area.
Agency officials are warning that large volcanic rocks may fall within about a 3-kilometer radius from the crater, and that pyroclastic flows could travel within about a 2-kilometer radius.
They are also urging people to beware of pressure waves caused by an explosive eruption that could break window panes.
