Friday marks five years since Japan's deadliest postwar volcanic disaster occurred. Mount Ontake in central Japan erupted on September 27, 2014, leaving 58 people dead and five others unaccounted for.
Officials in the village of Otaki in Nagano Prefecture are holding a memorial service to mark the occasion. The village sits at the foot of the mountain.
People are being urged to stay away from Mount Asama in central Japan following a minor eruption at the volcano on Wednesday night.
The eruption occurred shortly after 10 p.m. at the mountain, which straddles Nagano and Gunma prefectures, prompting the Meteorological Agency to raise the volcanic alert level from 1 to 3, on a scale of 5.
Japan's Meteorological Agency says at least 21 volcanoes across the country are at risk of erupting at craters other than those that are being closely monitored.
The agency surveyed volcanoes after Mount Kusatsu-Shirane in Gunma Prefecture north of Tokyo erupted unexpectedly last year on January 23rd. One Self-Defense Force member died and 11 people were injured.
Plants are covering the peak of Mount Oyama on Miyakejima island south of Tokyo for the first time since the volcano erupted in July 2000.
"The amount of volcanic gases has significantly declined since last year, likely allowing plants to grow rapidly around the summit," said Hiroyoshi Higuchi, a professor emeritus of the University of Tokyo, who has been studying the ecosystem of the island each year since the eruption.