On receiving a new alert on the eruption in North Sumatra, 30,000 people to evacuated the region for the second time this week.
The Sep 3 eruption accounted for the third one this week following the first one on Sunday, Aug 29 and Monday, Aug 30.
The tremor from the latest eruption is said to be the strongest so far and was reportedly felt five miles away. Besides this, the entire Mount Sinabung shook for a span of five minutes.
The mushroom-shaped plume of smoke that emerged from the eruption has limited visibility in the region and led to the cancellation of domestic flights.
According to the Indonesia's volcano alert centre, the eruption is still on.
"It's still going off, even now. You can't see it because of the heavy fog around the crater but, according to our seismic recorder, there are still small eruptions," Surono, the head of the alert centre, is quoted as saying.
While scientists were caught off guard, there are fears that these eruptions could lead to more destructive explosion in the near future.
However, there is a possibility that the Mount Sinabung, which last erupted in 1600, will go back to sleep once it lets off some steam.