Mount Semeru in East Java erupted five times on Friday, with the volcano spewing ash as high as 900 meters above its peak.
Mount Semeru Observation Post Officer Liswanto said in a written statement on Friday that the ash column looked white to gray in color and was moving with moderate intensity toward the southwest.
The volcano is still on alert (Level III). The Volcanology and Geological Hazard Mitigation Center (PVMBG) has appealed to residents to refrain from carrying out activities in the southeastern part of the volcano along the Besuk Kobokan River up to a distance of 13 kilometers from its peak.
They have also been asked not to carry out activities within a 500-meter radius of the river bank along Besuk Kobokan.
Residents have also been prohibited from carrying out activities within a 5-kilometer radius of the crater or peak of Mount Semeru because of the risk of injury from stones ejected by the volcano.
They have been asked to remain vigilant against the potential for hot clouds and lava avalanches along river flows or valleys from the peak of Mount Semeru, especially along Besuk Kobokan, Besuk Bang, Besuk Kembar, and Besuk Sat.
Further, they have been asked to be aware of the potential for lava in small rivers that are tributaries of the Besuk Kobokan river.