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Abstract: The mud volcano known as LUSI first erupted in May 2006 in East Java, Indonesia. The eruption has continued for over two years, and potentially will continue for many years to come, impacting an ever larger area. An obvious and significant question is how extensive the impacted area will become in the coming years. The answer is important for planning scenarios for the relocation of people and infrastructure and for managing the environment and economy. To make such a prediction, an understanding of the geological processes controlling the mud volcanic evolution is needed. A three-dimensional simulation model was built to predict the area affected by the mudflow over a ten-year period, with a special focus on the period from December 2007 until June 2010. The primary model inputs are the mud debit rate, the rate of subsidence and the topography. The model prediction was validated at the December 2007 time step by comparing the results with satellite images from the same period. The simulation was found to provide a good approximation for the mud overflow and growth. The results indicate that the mudflow tends to spread to the west and particularly to the east and north from the currently inundated area. The model predicts that in June 2010 the peak of the mud volcano will have risen 26 m above the original ground level, and the maximum subsidence will have been −63 m below the original ground level. The dynamic subsurface condition in the area creates geohazard risks, and these are also discussed in this paper. [Copyright &y& Elsevier]

Abstract: Following the Yogyakarta earthquake on May 27th, 2006, the subsequent eruption of a mud volcano has been closely observed and analyzed by the geological community. The mud volcano, known as LUSI, began erupting near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia. LUSI offers a unique opportunity to study the genesis and development of a mud volcano. For the first time, this paper presents all raw and interpreted drilling data, so any interested party can perform their own assessment. Our study suggests that LUSI mud volcano was a naturally occurring mud volcano in an area prone for its mud volcanism. Pressure analysis done on the Banjarpanji well shows that the pressure exerted at the well is lower than the fracture pressure at the last casing shoe, and suggests that the well was intact and did not suffer an underground blowout. This is further supported by evidence and observation made during drilling (such as circulation was done on an open BOP) and subsequent relief wells (Sonan and temperature log runs). This study offers a different alternative to earlier hypothesis that events at the Banjarpanji well were the trigger for the LUSI mud volcano. More work is needed by the scientific community to study the sequence of events in order to explain and clarify the real trigger of LUSI. [Copyright &y& Elsevier]