LAUSR

Abstract In May 2018, a major eruption occurred in the lower East Rift Zone of the Kīlauea volcano. The eruption started with the collapse of the Pu'u 'Ō'ō crater followed by a large downrift dike intrusion for more than 20 km in a well instrumented region. This large volcanic event is a rare opportunity to infer the dynamics of magma transfer that is often difficult to capture. In this study, we use seismological records to infer the migration of the dike. We detect, pick and locate more than 6000 earthquakes during the course of the magma intrusion. Using these locations together with near-field seismic amplitudes, we can precisely reconstruct the progression of the dike over time. We show that this migration is consistent with a logarithmic model of dike growth connected to a feeding magma chamber. The decrease of pressure inside the reservoir is also consistent with the dike propagation model derived from our observations. This work encourages real time monitoring of magma intrusions from the combination of seismological data and physical models.