Exploding shallow marine volcanoes: how does pumice from the vent differ from pumice making a raft?

  • Exploding shallow marine volcanoes: how does pumice from the vent differ from pumice making a raft?

Study Level

VRES

Supervisors

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Professor Scott Bryan

Overview

More than 21,000 km of submarine volcanoes front subduction zones, many of which lie in shallow water close to inhabited areas. Eruptions at these volcanoes can be explosive and may have significant impacts on nearby communities (as witnessed this year with the January 15 eruption of the Hunga Tonga Hunga hapa’ai volcano in Tonga), or generate pumice rafts that prolong impact at remote locations (as experienced in Japan in late 2021 following the Fukutoku Oka-no-Ba eruption). For the first time, samples of a shallow marine explosive eruption have been collected from the buoyant pumice raft and from the seafloor at the vent of Volcano 0403-091, Tonga.

Research activities

Preliminary data indicate that pumice  deposited on the seafloor around the vent is dense and has variable vesicularity, while pumice that produced the floating raft is low density and highly vesicular. This indicates that pumice material is being sorted by the ocean water on eruption and seafloor pumice and raft pumice do not fully capture or represent the diversity of erupted material in explosive eruptions. The project will substantially utilise Helium pcynometry for density characterisation of pumice samples supported by some textural analysis of the pumice material using optical or scanning electron microscopes. Density analysis will be done using facilities within the Central Analytical Research Facility at QUT.

Outcomes

This project will provide:

  • a much more detailed view of the density and therefore vesicularity characteristics of pumice produced in shallow marine explosive eruptions
  • new constraints on eruption dynamics of shallow marine explosive eruptions and the fate of pumice – to be buoyant and remain afloat or to sink to the seafloor.

Skills and experience

You should have:

  • an earth science background
  • previous research experiences in:
    • igneous petrology
    • volcanology, or
    • having worked on material properties in CARF.

Apply

Contact supervisors for more information:

Professor Scott Bryan