Drilling or an earthquake in the Porong subdistrict of East Java province, Indonesia, may have resulted in the Sidoarjo mud flow on May 29, 2006. The mud covered about 440 hectares, (2.73 mi2), and inundated four villages, homes, roads, rice fields, and factories, displacing about 24,000 people and killing 14. The gas exploration company involved was operated by PT Lapindo Brantas and the earthquake that may have triggered the mud volcano was the 6.3 magnitude Yogyakarta earthquake of May 27, 2006. According to geologists who have been monitoring Lusi and the surrounding area, the system is beginning to show signs of catastrophic collapse. It was forecasted that the region could sag the vent and surrounding area by up to in the next decade. In March 2008, the scientists observed drops of up to in one night. Most of the subsidence in the area around the volcano is more gradual, at around per day. A study by a group of Indonesian geo-scientists led by Bambang Istadi predicted the area affected by the mudflow over a ten-year period. More recent studies carried out in 2011 predict that the mud will flow for another 20 years, or even longer. Now named Lusi – a contraction of "Lumpur Sidoarjo", where "lumpur" is the Indonesian word for "mud" – the eruption represent an active hybrid system.