 It last had an eruption in 1963-64 and before that it was a hundred years. So a number of these volcanoes have long repose intervals and we get a better idea of their behaviour if they erupt more frequently. Sometimes the magma can rise but that need not necessarily lead to an eruption. And there have been some wonderful cases where things have just stalled. For example in the case of Raubowl on the island of New Britain in Papua New Guinea there was a major seismic crisis just like the one occurring below Agong in 1981. And many people thought well this is about to erupt but everything stalled, everything calmed down. But then 13 years later in 1994 with not that much precursor activity the thing blew up and the ash column reached the stratosphere, it had a significant local effect. The town of Raubowl was evacuated and is officially not being re-occupied. So you can get different times of how long it takes between a seismic crisis and an eruption and it can take a long period of time between. In the case of Agong it has progressed to the point where Fragmental Rock ash is coming out of the top of the volcano. That's bad news for people in Bali because now it looks like the magmatic system has fractured its way up towards the surface and once that takes place you can get a runaway effect that a small eruptions of the type that are occurring now could lead to a much bigger one in the order of days to weeks. But it may calm down again, everything become quite tranquil and the people would be safe to go back to where they were living. For more videos and articles like our Facebook page