The Sidoarjo mud flow or Lapindo mud, also informally abbreviated as Lusi, a contraction of Lumpur Sidoarjo (lumpur is the Indonesian word for mud), is a mud volcano in the subdistrict of Porong, Sidoarjo in East Java, Indonesia that has been ongoing since May 2006. The biggest mud volcano in the world was created by the blowout of a natural gas well drilled by PT Lapindo Brantas, although company officials contend that it was caused by a distant earthquake.
Approximately 30,000 m³ (1 million cubic feet) of mud — equivalent to the contents of a dozen Olympic-size swimming pools — are expelled per day. It is expected that the flow will continue for the next 30 years. Although the Sidoarjo mud flow has been contained by levees since November 2008, resultant flooding regularly disrupts local highways and villages. Further breakouts of mud are still possible.
More info : en.wikipedia.org/wiki/Sidoarjo_mud_flow