Tracking dike propagation leading to the 2018 Kīlauea eruption

Olivier Lengliné,Zacharie Duputel,P.G Okubo

doi:10.1016/j.epsl.2020.116653

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.

Highlights

Lateral dike intrusions are ubiquitous features of basaltic volcanoes (Walker and Sigurdsson, 2000)
We focus on the dike intrusion of May 2018 that propagated in the Middle East Rift Zone (MERZ) of Kılauea volcano (Fig. 1)
We track the dike intrusion that led to the 2018 Kılauea eruption in the Lower East Rift Zone (LERZ)

Summary

Introduction

Lateral dike intrusions are ubiquitous features of basaltic volcanoes (Walker and Sigurdsson, 2000). For example at Piton de la Fournaise volcano, magma tracked by earthquake locations and geodetic signals, is first transferred vertically before propagating into the rift zones where eruptive vents are formed (e.g, Smittarello et al, 2019; Duputel et al, 2019) This last stage of lateral magma migration before eruptions is of interest in order to assess the location of the future eruptive site. Earthquake migration speed is usually high at the beginning of the intrusion and decays with time before stopping This behavior is generally interpreted as the consequence of the decrease in the driving pressure resulting from the progressive drainage of the feeding magma reservoir (Rivalta, 2010).

Results

Discussion

Conclusion