Study finds Indonesian mudflow was triggered by gas drilling

Ars Technica : Since May 2006, mud has been mysteriously erupting on the Indonesian island of Java. Nine years of mudflow have resulted in the displacement of some 39 700 people and $2.7 billion in damages. First thought to have been triggered by the magnitude 6.3 Yogyakarta earthquake, which occurred two days before the eruption started, the Lusi mudflow has now been attributed to natural gas drilling operations in the area. Mark Tingay of the University of Adelaide and colleagues arrived at that conclusion by analyzing gas measurements made in the exploratory well’s borehole just before and just after the earthquake. They detected the presence of hydrogen sulfide gas, which could only have come from the pressurized aquifer that the drilling was tapping into. They say that the puncturing of that aquifer allowed the pressurized water to escape up the borehole, which had no protective steel casing. The thick clay surrounding the borehole fractured and created the mudflow that has plagued the area ever since.