Jakarta, April 6 -- Indonesia has heightened safety measures after Mount Semeru, the highest volcano on Java Island, erupted repeatedly on April 6, raising concerns over potential natural hazards in East Java.

According to Indonesia's Centre for Volcanology and Geological Hazard Mitigation (PVMBG), the eruptions sent columns of ash rising up to 1,100m above the summit. The ash, described as white to grey, drifted southward at moderate intensity.

Observation data showed that the volcano erupted at least seven times from shortly after midnight, with the first recorded at 12:38am local time. The most powerful eruption occurred at 6:51am, when the ash plume reached its peak height of around 1,100m.

Authorities have tightened safety measure...