Mount Merapi volcano emits smoke as it is seen from Kinahrejo village near Yogyakarta October 26, 2010. Indonesia's Mount Merapi erupted on Tuesday, prompting terrified villagers to flee and join the thousands already evacuated from its slopes. [Xinhua/Reuters]

The frequency of hot ash emissions from Indonesia's Mount Merapi volcano increased as eight times of emissions were recorded until 7:34 pm. on Friday, an official said Saturday.

"The emissions of hot clouds are normal before a new dome of lava forms," head of the Vulcanology Technology Development and Assessment (BPPTK), Subandriyo, said.

Based on data from BPPTK, there were three emissions on Thursday.

The mountain's eruption on Tuesday were marked by hot gas emissions which were a direct blast in nature that would open the mountain's peak so that the possibility of a repeat eruption like the first ones would be small, Antara news agency quoted the official as saying.

He however predicted that hot clouds would continue to come out of the mountain everyday and this would possibly last quite a long time.

"If the choke at the peak has been opened the magma would come out and form a new lava dome. Right now however we are not able to monitor conditions at the peak," he said.

One of the worries is if the building of the lava dome ran fast namely between 100,000 to 200,000 meter cubic per day.

A lava dome which is built quickly will have the potential to fall if it is placed on an unstable position and the fall could go as far as six to seven kilometers away.

He said the danger which still remains after eruptions is lava floods which may happen if rain falls very heavily.

Thirty-three people were killed and dozens of others injured so far because of the hot volcanic ash from the mountain with some 47, 000 people who live around Mount Merapi evacuated.

Mount Merapi, 2,968 meters high, is located in dessely populated Central Java. It last erupted in 2006 killing two people, after an eruption in 1994 left 60 people dead.

More than 1,000 people were killed in its eruption in 1930.

Indonesian archipelago, which lies on the Pacific Ring of Fire with frequent earthquakes and volcano eruptions, has 129 active volcanoes.