UC Berkeley

The Lusi mud eruption, in East Java, Indonesia, began in May 2006 and continues to the present. Previous analyses of surface deformation data suggested an exponential decay of the pressure in the mud source but did not constrain the location, geometry, and evolution of the possible source(s) of the erupting mud and fluids. To map the surface deformation, we employ multitemporal interferometric synthetic aperture radar and analyze a well-populated L-band data set acquired by the Advanced Land Observing Satellite (ALOS) between May 2006 and April 2011. We then apply a time-dependent inverse modeling scheme. Volume changes occur in two regions beneath Lusi, at 0.3-2.0km and 3.5-4.75km depth. The cumulative volume change within the shallow source is ∼2-3 times larger than that of the deep source. The observation and model suggest that a shallow source plays a key role by supplying the erupting mud, but that additional fluids do ascend from depths >4km on eruptive timescales. Key Points Spatiotemporal map of the surface deformation associated with Lusi mud eruption Time-dependent source model of the Lusi and nearby gas field Revealing the deep and shallow sources of the Lusi and characterizing their relationship.