The volcano billowed smoke and ash from smaller eruptions last week, local media reported, but the new series of eruptions on the country's southern island of Kyushu was a significant increase of potentially dangerous activity, Japan's Meteorological Agency said in an Associated Press report.
The smoke forced the Kagoshima Airport to cancel all flights after 3 p.m. local time, an airport announcement read. The airport is about a 20-mile drive from the base of the volcano. It operates about 80 flights per day, the wire service reported.
A thick film of soot covered cars in Kirishima city at the base of the volcano, about 4,660 feet tall. People wore surgical masks and covered their mouths with towels, the AP reported. Others used umbrellas to shield themselves from the settling ash. Lava continued to simmer inside the crater, and the meteorological agency warned about the risk of dense volcanic rocks hurling through the air.
As of Tuesday, entry was restricted for the immediate area around the volcano, the AP reported. The volcano is among 110 active volcanoes in Japan, a prominent contribution to the Ring of Fire. The ring - a tracing of volatile tectonic plate activity in an arc from southern Chile up to Alaska and Japan and tapering off at New Zealand - is home to 90 percent of the world's earthquakes.
Officials cautioned people near Shinmoedake about the possibility of deadly pyroclastic flows. The flows are made up of lava blocks, pumice, ash and superheated volcanic gas that barrels down a volcano's slope to vaporize essentially anything in its path, resembling something like a tumbling avalanche that trades snow for piping-hot debris.
Volcanoes in Japan have been deadly in recent years. An eruption of Mount Ontake in 2014 killed about 60 people, many of them hikers, raising questions about the role of early warnings when activity such as escalating gas release is often a sign of an imminent eruption.
In January, an eruption at central Japan's Mount Kusatsu-Shirane killed a training soldier and injured 11 people in the resulting ash cloud.
The Shinmoedake volcano, which erupted in a similar fashion in 2011, might be recognizable for spy thriller fans. The 1967 James Bond film "You Only Live Twice" featured the volcano in its climatic scene involving the infiltration of a secret lair concealed deep within.
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