Mount Aso alert raised to level two; recovery of Taiwanese victims' helicopter delayed

Japan's Fukuoka District Meteorological Observatory has elevated the volcanic alert level for Mount Aso in Kumamoto Prefecture to level two, citing a significant increase in "volcanic tremors."

This heightened alert has led to the postponement of a planned operation to recover a crashed helicopter and the remains of three Taiwanese victims from the volcano's first crater. The recovery, initially scheduled for June 22, is now delayed due to the increased volcanic activity.

The observatory noted that the amplitude of "volcanic tremors" has been consistently large since around 9 a.m. local time, indicating escalating volcanic activity. Furthermore, daily sulfur dioxide emissions have risen from 900 tons to 1,700 tons, prompting concerns about potential eruptions.

Authorities have warned of the possibility of large volcanic bombs and pyroclastic flows within a 1-kilometer radius of the Naka-dake crater. The alert level was previously raised to two in July 2025 and later lowered back to one. Mount Aso last erupted in October 2021.