The deep subsurface structure beneath Lusi and the adjacent volcanic chain inferred from local travel-time tomography

Since 2006, the Lusi mud eruption is ongoing in the northeast of Java Island, Indonesia. We perform a 3D seismic tomography of the area surrounding Lusi and the adjacent Arjuno-Welirang volcanic complex using P wave arrivals of 797 local earthquakes recorded on 31 seismic stations for two years between 2015 and 2016. Resolution tests show that we can reasonably well constrain the subsurface velocity structure beneath Lusi down to a depth of 20 km. The results of our tomography reveal that Lusi has a shallow plumbing system that is interconnected with the neighboring Penanggungan volcano. Their joint system reaches down to a depth of 20 km. The Arjuno-Welirang volcanic complex has its own deep-rooted plumbing system that might be connected to Penanggungan volcano and Lusi along the Watukosek Fault zone. The connection of Lusi with this large reservoir volume elucidates the longevity of the Lusi eruption. (C) 2020 The Authors. Published by Elsevier B.V.