Paper No. 11
Presentation Time: 3:45 PM
THE LUSI ERUPTION WAS NOT CAUSED BY AN EARTHQUAKE
The Lusi mud eruption in East Java, Indonesia has displaced tens of thousands of people with economic costs that exceed $4 billion USD to date. Consequently, understanding the cause and future of the eruption are important. There has been considerable debate as to whether the eruption was triggered by the MW 6.3 Yogyakarta earthquake, which struck two days prior to the eruption, or by drilling operations at a gas exploration well (BJP-1) ~200 m from the ~700 m lineament, along which mud first erupted. A recent letter by Lupi et al. (Nature Geoscience, 2013) argues for an earthquake trigger, invoking the presence of a seismically fast structure that amplifies seismic shaking in the mud source region. The absence of an eruption during larger and closer earthquakes reveals that an earthquake trigger is unlikely. Furthermore, the high seismic velocities, central to the model of Lupi et al. , are impossibly high and are primarily artifacts associated with steel casing installed in the well where the velocities were measured. Finally, the stress changes caused by drilling operations greatly exceeded those produced by the earthquake. Assuming no major changes in plumbing, we conclude by using satellite InSAR to reveal the evolution of surface deformation caused by the eruption and predict a 10 fold decrease in discharge in the next 5 years.[CC1]
[CC1]I think it is stronger to end the sentence and the abstract not on an assumption