Interactions of magmatic intrusions with the multiyear flank instability at Anak Krakatau volcano, Indonesia: Insights from InSAR and analogue modeling

Abstract Volcano flank collapses have been documented at ocean islands worldwide and are capable of triggering devastating tsunamis, but little is known about the precursory processes deformation changes prior to failure. This makes 22 December 2018 collapse Anak Krakatau in Indonesia a key event geosciences. Here, we provide direct insight into final collapse. We analyzed interferometric synthetic aperture radar (InSAR) data from 2014 studied link between trend intrusion occurrence through analogue modeling. found that was already moving least 4 yr collapse, consistent with slow décollement slip. Movement rates averaged ~27 cm/yr, they underwent two accelerations coinciding distinct events January/February 2017 June 2018. Analogue models suggest these occurred by (re)activation fault linked short episode magma intrusion. During intrusion, observed change internal faults, where outward-directed accelerated while inward faults became partially blocked. These observations unstable oceanic flanks do not disintegrate abruptly, their preceded observable deformations can be new intrusions.