Washington, May 29 : The fastest-growing mud volcano in the world, called Lusi, is collapsing and can even cave down to the depths of more than 140 metres, affecting the surrounding environment, says a new research.
In time with the second anniversary (May 29) of the eruption on the Indonesian island of Java, scientists, based on their findings on Global Positioning System (GPS) and satellite measurements, have cautioned that Lusi's centre is collapsing by up to three metres overnight.
And the research team, from Durham University UK, and the Institute of Technology Bandung, in Indonesia, fears that such sudden collapses may initiate a caldera - a large basin-shaped volcanic depression.
It was on May 29, 2006 that Lusi erupted for the first time in the Porong sub-district of Sidoarjo, near Indonesia's second city of Surabaya, East Java, and now covers seven square kilometres and is 20 metres thick.
Also, in January 2007 Durham University attributed the causes and impact of Lusi, to a manmade eruption, caused by the drilling of a nearby exploratory borehole looking for gas.
Already, 14 people have been killed and 30,000 people have been evacuated from the area. More than 10,000 homes have been destroyed while schools, offices and factories have also been wiped out and a major impact on the wider marine and coastal environment is expected. And the researchers are saying that the subsidence data may help in finding out how much of the local area will be affected by Lusi.
By using GPS and satellite data recorded between June 2006 and September 2007, the researchers showed the area affected by Lusi had subsided by between 0.5 metres and 14.5 metres per year.
Also, they observed that if Lusi erupted continuously for three to 10 years at the constant rates measured during 2007, then the central part of the volcano could subside by between 44 metres and 146 metres - 26 metres longer than a football pitch.
Thus, they have proposed that the subsidence is due to the weight of mud and collapse of rock strata due to the excavation of mud from beneath the surface.
It was also found that while some parts of Sidoarjo are subsiding others are rising suggesting that the Watukosek fault system has been reactivated due to the eruption.
"In the two years since she first erupted Lusi has continued to grow. Our research is fundamental if we are to understand the long-term effects of the mud volcano on the local and wider environment and population," said co-author Professor Richard Davies, of Durham University's Centre for Research into Earth Energy Systems (CeREES).
He added: "Sidoarjo is a populated region and is collapsing as a result of the birth and growth of Lusi. This could continue to have a significant environmental impact on the surrounding area for years to come. If we establish how long the volcano will continue to erupt for then the subsidence data will allow us to assess the area that will ultimately be affected by this disaster. This could have implications for future plans aimed at minimising the volcano's overall impact."
The findings will be published in the journal Environmental Geology.