Cleanup work in areas surrounding Mount Aso began Thursday, a day after an eruption at the volcano caused pyroclastic flows for the first time since 2016.

A street-sweeping truck cleared away ash in the town of Takamori, Kumamoto Prefecture, with workers expected to collect several dozen tons of volcanic debris in a day, according to town authorities.

The eruption from Mount Aso's No. 1 Nakadake crater sent a column of ash about 3,500 meters into the air. The volcanic alert level for the mountain was raised to 3 on a scale of 5, with entry to areas within 2 kilometers of the crater restricted.

"Living here, the risk of being affected by volcanic ash is unavoidable. I want to clean up the roads so that they can be used with peace of mind," said Toru Iwashita, a senior official from Takamori which is located just south of the volcano.

There were 16 climbers on the volcano at the time of the eruption, but all walked off the mountain uninjured. In order for other climbers to be aware of the situation, the city of Aso set up a temporary office at the foot of the volcano.

Kumamoto Gov. Ikuo Kabashima said after visiting Takamori and the city of Aso that while "the vicinity of the crater is off-limits, unrestricted areas are not dangerous to visit."

Despite this, he expressed concern about the eruption's possible impact on tourism and farming in the prefecture.

However, on Thursday, high school students visiting on a field trip from Osaka were unperturbed as they watched smoke billowing from the volcano from an area outside of the no-go zone.

According to an investigation by the Meteorological Agency, evidence of pyroclastic flows was observed 1.6 km north of the Nakadake crater's center and 1 km to the west.