Skip to main content
Log in

How to turn off a lava lake? A petrological investigation of the 2018 intra-caldera and submarine eruptions of Ambrym volcano

  • Research Article
  • Published:
Bulletin of Volcanology Aims and scope Submit manuscript

Abstract

In December 2018, an unusually large intra- and extra-caldera eruption took place at Ambrym volcano (Vanuatu). The eruption drained the volcano’s five active lava lakes and terminated, at least momentarily, the surface activity that had been ongoing for decades to hundreds of years, sustaining the largest recorded persistent degassing on the planet. Here, we investigate the mechanisms and dynamics of this major eruption. We use major elements and volatiles in olivine and clinopyroxene-hosted melt inclusions, embayments, crystals and matrix glasses together with clinopyroxene geobarometry as well as olivine and clinopyroxene geothermometry and diffusion modelling in crystals and embayments to reconstruct the chronology and timing of the subsurface processes that accompanied the eruption. We find that the eruption began with the meeting, mingling and limited chemical mixing of mostly two magma bodies occupying similar vertical but different horizontal locations in the crust, one corresponding to the main plumbing system at Ambrym that fed the lava lakes and the other corresponding to an older, previously cutoff and more chemically evolved branch of the plumbing system. Within the primitive magma, two texturally distinct components—one microlite rich and one microlite poor—can further be identified. The 2018 eruption hence provides a detailed image of Ambrym’s complex plumbing system. Our diffusion timescales and geobarometric estimates coincide closely with geophysical observations. They point to a reconnection of the evolved magmatic branch with the main system occurring less than 10 h prior to the intra-caldera eruption and a period of 2 days for the subsequent > 30-km lateral magma transport along a deeper dike prior to submarine eruption just off the SE coast of the island with the more primitive magma reaching first followed by mingled magma containing both compositions. Magma ascent rates are estimated at 95 ± 24 m/s in the last ~ 2.5 km of ascent during the intra-caldera eruption and at 80 ± 6 m/s in the last ~ 4 km of ascent during the submarine eruption. Comparison with other lava lake draining eruptions reveals striking similarities both in terms of precursory activity, with lake level rising prior to the eruption in all cases, and in terms of plumbing system organization with the presence of peripheral magma pockets, isolated from the main magmatic system but that can be mobilized and erupted when met by dikes propagating laterally from the main system.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

Similar content being viewed by others

References

Download references

Acknowledgements

This research was conducted as part of the Trail by Fire II – Closing the Ring project (PI: Y. Moussallam) with support from National Geographic (grant number CP-122R-17) the Rolex Awards for Enterprise and the French National Research Institute for Development (IRD). We thank Nordine Bouden and Etienne Deloule of CRPG (France) for their precious guidance during SIMS analysis. We thank Mhammed Benbakkar for ICP-AES analyses and Claire Fonquernie for help with sample preparation. We are grateful for the constructive reviews provided by Nicole Métrich and two anonymous reviewers on an earlier version of this manuscript and to Nicole Métrich for editorial handling.

Funding

M.B. acknowledges support from the French National Research Agency (ANR) for funding the VOLCPLUME project (ANR-15-CE04-0003-01).

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Yves Moussallam.

Additional information

Editorial responsibility: N. Métrich; Deputy Executive Editor: J. Tadeucci

This paper constitutes part of a topical collection: Open-vent volcanoes

Supplementary information

ESM 1

(XLSX 191 kb)

ESM 2

(DOCX 763 kb)

(MP4 336248 kb)

(MP4 32397 kb)

ESM 5

(ZIP 542 mb)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Moussallam, Y., Médard, E., Georgeais, G. et al. How to turn off a lava lake? A petrological investigation of the 2018 intra-caldera and submarine eruptions of Ambrym volcano. Bull Volcanol 83, 36 (2021). https://doi.org/10.1007/s00445-021-01455-2

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: https://doi.org/10.1007/s00445-021-01455-2

Keywords

Navigation