Small eruption at Hokkaido's Tokachidake volcano — first since 2004

A small eruption occurred Wednesday at Tokachidake, an active volcano on Japan's northern island of Hokkaido, local meteorological authorities announced. It was the first eruption observed at the volcano since February 2004 — about 22 years ago.

According to the Sapporo Regional Meteorological Observatory, the eruption began at around 11:07 a.m. Wednesday, sending black smoke soaring roughly 200 meters into the air.

The eruption was accompanied by about 45 seconds of volcanic tremor. Volcanic tremor refers to continuous low-frequency vibrations generated when magma, volcanic gases or hot water pass through underground conduits beneath a volcano.

The observatory urged people within roughly 1.5 kilometers of the crater to watch for large volcanic rocks ejected during eruptions and to stay away from hazardous areas in accordance with instructions from local authorities.

No large volcanic rocks were reported to have been thrown clear of the crater, and no casualties or property damage have been reported. Authorities said further small eruptions could recur and decided to keep the volcanic alert level at 2, which restricts entry to the area around the crater.

Tokachidake has shown signs of heightened volcanic activity since March, including ground deformation, increased volcanic gas emissions and seismic activity around the crater. In response, the observatory raised the volcanic alert level from 1 — which advises awareness of the active volcano — to 2 in June.