Lusi Mud Eruption Research Articles

Lusi mud eruption triggered by geometric focusing of seismic waves

The Lusi mud eruption in Indonesia has been ongoing since 2006. Numerical simulations show that a parabolic-shaped layer in the rock surrounding the site of the Lusi eruption could have amplified and focussed incoming seismic energy from an earthquake, which then triggered the mud eruption.

Evolution and future of the Lusi mud eruption inferred from ground deformation

AbstractThe ongoing eruption of the Lusi mud volcano in East Java, Indonesia offers the unprecedented opportunity to study a large eruption from its beginning to its eventual end. We use new observations of ground deformation obtained from multitemporal interferometric analysis of L‐band synthetic aperture radar data to show that Lusi will stop erupting much sooner than previously anticipated. Using principal component analysis, we find that the rate of ground deformation, and by implication, pressure in the mud source region, has been decaying exponentially with an e‐folding time scale of 2.1 ± 0.4 years. We anticipate that discharge will decrease to 10% of the present rate in 5 years.

A prediction of the longevity of the Lusi mud eruption, Indonesia

A mud eruption, nicknamed Lusi, began near Sidoarjo, East Java, in May 2006. It has discharged ∼ 10 4–10 5 m 3/day of mud ever since. In order to understand the nature of the eruption and its potential longevity, we develop a model for the coupled evolution of the mud source and ascent of mud through a conduit to the surface. The ascent of the mud is driven by overpressure in the mud source and by the exsolution and expansion of dissolved gasses. We assume that erupted fluids originate in the mud source region. Mobilization of the mud is caused by elastic stresses induced by mud evacuation from the subsurface. We perform Monte Carlo simulations to explore model outcomes while perturbing the unknown material properties of the mud and surrounding medium. Using our preferred model, we calculate a 50% chance of the eruption lasting < 41 yrs and a 33% chance that it lasts > 84 yrs. Eruptions often end with the formation of a caldera, but longer eruptions are less likely to form a caldera. Model predictions can be refined with additional, but currently unavailable constraints: more precise estimates of mud discharge, the yielding behavior of the materials in the subsurface, total gas content in the mud source, and identification of any erupted fluids that do not originate in the mud source.

Subsidence associated with the LUSI mud eruption, East Java, investigated by SAR interferometry

A mud volcano LUSI initiated its eruption on 29 May 2006, adjacent to a hydrocarbon exploration well in East Java. Ground subsidence in the vicinity of the LUSI eruptive vent was well recorded by a Synthetic Aperture Radar (SAR) PALSAR onboard the Japanese ALOS satellite. We apply an Interferometric SAR (InSAR) technique on ten PALSAR data scenes, acquired between 19 May 2006 and 21 May 2007, in order to obtain continuous maps of ground displacements around LUSI. Although the displacements in the area closest to the eruptive vent (spatial extension of about 1.5 km) are not detectable because of the erupted mud, all the processed interferograms indicate subsidence in an ellipsoidal area of approximately 4 km (north–south) × 3 km (east–west), centered at the main eruptive vent. In particular, interferograms spanning the first four months until 4 Oct. 2006 and the subsequent 46 days between 4 Oct. 2006 and 19 Nov. 2006 show at least about 70 cm and 80 cm of displacements away from the satellite, respectively. Possible causes of the subsidence, i.e., 1) loading effect of the erupted mud, 2) creation of a cylindrical mud conduit, and 3) pressure decrease and depletion of materials at depth, are investigated. The effects of the first two causes are found to be insufficient to explain the total amount of subsidence observed in the first six months. The third possibility is quantitatively examined using a boundary element approach by modeling the source of deformation as a deflating oblate spheroid. The spheroid is estimated to lie at depths of a few hundred to a thousand meters. The estimated depths are significantly shallower than determined from analyses of erupted mud samples; the difference is explained by presence of significant amount of inelastic deformation including compaction and downward transfer of material.

Triggering of the Lusi mud eruption: Earthquake versus drilling initiation

ABSTRACTThe Lusi mud volcano in East Java has erupted unabated for almost 2 yr, fl ooding an area of 7 km 2 and displacing more than 25,000 people. Despite its disastrous impact, the mechanism for triggering the Lusi eruption remains highly controversial; two distinct mechanisms have been proposed. One hypothesis suggests that the eruption was triggered by the M w 6.3 earth-quake that struck Yogyakarta (250 km from Lusi) two days before the eruption. However, an examination of static and dynamic stress changes and stress transfer mechanisms indicates that the Yogyakarta earthquake was at least an order of magnitude too small to reactivate faults and open fl uid fl ow pathways under Lusi. An alternate theory suggests that Lusi was triggered by a blowout following drilling problems in the nearby Banjar Panji-1 well. Blowouts result from an inability to control pore fl uid intakes into the borehole and typically occur when the drilling win-dow (fracture pressure minus pore pressure) is approximately zero and when there is insuffi cient protective casing of the well bore. Pore and fracture pressure data from Banjar Panji-1 indicate that the well had a narrow drilling window of only 0–2.3 MPa. Furthermore, two planned casing points were skipped during drilling, resulting in 1742 m of unprotected borehole. The combina-tion of hazardously narrow drilling window and long uncased borehole would have made drill-ing problems in Banjar Panji-1 diffi cult to control, placing the well at high risk of blowing out. Furthermore, well-bore pressures following drilling problems in Banjar Panji-1 reached magni-tudes in excess of the fracture pressure and thus were suffi cient to create fl uid fl ow pathways in the subsurface. Therefore, we suggest that no viable method is known by which the Yogyakarta earthquake could have triggered the mudfl ow and that a blowout in the Banjar Panji-1 well was the most likely mechanism for triggering the Lusi eruption.Keywords: