Mount Sinabung in Karo regency, North Sumatra, was still spewing lava as of Monday afternoon after an eruption on Sunday evening.
Officials warned residents living on the slopes of the mountain to stay alert - especially those within a 3-kilometer radius of the crater - as further eruptions could occur.
Armen Putra, an officer monitoring the mountain, said that activity at Mt. Sinabung was higher than usual in frequency. He said based on the results of observations carried out over recent days, the volcano would likely see another eruption. He said he could not predict the time of the next eruption, but believed it would happen soon.
"The potential for another eruption is still big. We can tell that from the molten lava flows that keep coming out of Mt. Sinabung's crater," he told The Jakarta Post over the phone on Monday.
Mt. Sinabung saw its latest eruption on Sunday at 7:29 p.m. Armen said the eruption was not particularly powerful, but that the volcano discharged hot ash clouds to a distance of 4.5 kilometers to the southeast, toward Sei Bekerah village.
The height of the volcanic ash clouds was not clear because visibility was blocked by haze. However, residents reported that the ash had reached Sukanalu village, around 4.5 kilometers away from Mt. Sinabung.
Mt. Sinabung Eruption Media Center coordinator Jhonson Tarigan said there had been no additional influx of evacuees following the current eruption.
"The number of evacuees was still 12,809 people, or 3,996 families. This is the data of evacuees who have not returned home since the Sinabung eruption last year," he told the Post on Monday.
He said the activity at the evacuation centre remained normal. According to Jhonson, many residents seemed to have a good ability to handle their fear of eruptions as they have been faced with such incidents repeatedly over the past few years.
"The residents have become used to the eruptions of Mt. Sinabung, so they are not afraid anymore.
The government has asked them to stay on guard and wear face masks," he said.
After experiencing no volcanic activity for more than four centuries, Mt. Sinabung erupted in August 2010. Another eruption occurred the following year.
Then, after being dormant for almost two years, the mountain erupted again in September 2013, killing 14 residents and injuring numerous others. Since then, tens of thousands of residents have been displaced.
Ongoing eruptions in the months following the 2013 event not only greatly affected agriculture in the area, but has also threatened tourism, due to uncertainty regarding when volcanic activity would cease.
National Disaster Mitigation Agency (BNPB) spokesman Sutopo Purwo Nugroho said the central government had disbursed financial aid for renting and repairing houses for evacuees who had been displaced since last year's eruption.
He said houses that had been renovated included 258 homes in Sukanalu village, 91 in Selandi Lama village, 205 in Sigarang-garang, 113 in Kebayakan, 152 in Kutarakyat and 100 in Kutagugung.