The Geological Agency raised Sinabung from Level II to Level III after detecting a significant increase in volcanic activity. The agency says the eruption was still ongoing when its special report was issued and warns that a larger eruption remains possible.
Sinabung eruption sends ash 3,500 meters above summit
The eruption started at 10:17 a.m. and ash continued emerging from the summit more than an hour later. The plume was moving east and southeast, putting nearby areas in the path of the ash.
https://www.antaranews.com/berita/5718481/gunung-sinabung-erupsi-kolom-abu-menjangkau-3500-meter
85 volcanic earthquakes recorded before eruption
This is probably the strongest escalation signal. In the period immediately before the eruption, monitoring recorded 85 volcanic earthquakes, followed by the eruption with a seismic amplitude reaching 120 mm.
Ash blankets nearby areas and authorities distribute masks
Ash reached nearby areas including Berastagi, while authorities distributed protective masks. There were no immediate reports of casualties or flight disruptions, but residents and tourists were told to stay away from areas within 6 kilometers of the summit.
https://apnews.com/article/8cf0866bfa87e126919da2d134bfcba5