LAUSR

Lusi is a sediment‐hosted geothermal system relentlessly erupting since May 2006 in the East Java back‐arc sedimentary basin. Lusi provides the unprecedented opportunity to study the development of the early phases of a new‐born piercement structure and its impact on society. In order to investigate the shallow plumbing system of this large‐scale eruption, we deployed a pool of 25 IRIS V‐Fullwavers to conduct a 3D deep electrical resistivity tomography extending over ∼15 km2 around the eruption site. The inverted data reveal the structure of the subsided area hosting the region where a mix of groundwater, mud breccia, hydrocarbons and boiling hydrothermal fluids are stored. Our investigation also points out the link between a well‐developed fault system and the upwelling of the deep‐seated fluids that initiated, and still drive, the development of the new‐born Lusi eruption.