A woman walks as Mount Sinabung spews
© AFP/Muhammad Zulfan Dalimunthe
A woman walks as Mount Sinabung spews smoke into the air in Karo, North Sumatra, on Aug 23.
The Volcanology and Geological Hazard Mitigation Center (PVMBG) has warned the public to avoid Mount Sinabung in Karo regency, North Sumatra, and has evacuated nearby settlements as the volcano spews hot ash.

According to the PVMBG the volcano emitted a burst of hot ash at 12:51 p.m. on Sunday. The ash drifted some 1,500 meters southeast of the crater. It unleashed more ash, which drifted some 2,500 meters southeast, at 8:58 p.m. on the same day.

"We need to be cautious because the lava dome in Mt. Sinabung is growing every day. The condition can lead to a huge flow of hot ash," Mt. Sinabung observation team member Muhammad Nurul Asrori told The Jakarta Post on Monday.

A lava dome, or volcanic dome, is a steep mound that forms as lava reaches the earth's surface. It can gradually expand as additional lava is forced into its interior. The pressure on the interior of the dome can cause a fracture in the solidified outer shell that can allow lava or other volcanic material to escape onto the dome's flanks. If the lava dome grows rapidly, it may collapse, spewing deadly volcanic material.

The PVMBG issued the warning after observing that many residents had remained on the mountain's slopes. The center said the area had become a danger zone and that residents needed to leave, adding that pyroclastic flow could outrun humans.

"Before it happens, it might be best for us to avoid [the volcano] because no one can survive the fast ash clouds flowing from Mt. Sinabung's craters," Asrori added.

Nine residents of Gamber village, Simpang Empat district in Karo regency were killed by volcanic ash when Mt. Sinabung erupted in 2016. The deadly eruption of the volcano in 2014 also claimed 16 lives.

"Residents within 4 to 5 kilometers southeast of Mt. Sinabung have been evacuated and relocated," Karo Disaster and Mitigation Agency (BPBD) acting chair Natanael Perangin-angin told the Post.

"The hot clouds are deadly. That is why we are continuing to coordinate with the Mt. Sinabung observation post regarding the development of volcanic activities," he added.

The latest string of eruptions occurred on Aug. 10 as Mt. Sinabung spewed a 5,000-meter-high column of volcanic ash and smoke from its peak.