About the project
Subduction zone volcanoes are notoriously dangerous and unpredictable. But did they behave differently when they were young? Here, pre-eruptive magmatic processes and timescales of a rare, young stratovolcano (Bagana, PNG) will be compared to an old stratovolcano (Etna) to explore how eruption size, style and timescales change as volcanoes age.
Volcanoes are fuelled by magmatic plumbing systems that connect the Earth’s mantle with the surface. Most present-day subduction zone volcanoes have mature plumbing systems that grew in size and complexity over long time periods[1], producing eruptions with diverse magma compositions, assembly mechanisms and explosivities. This diversity of eruption styles (effusive/explosive), sizes, and pre-eruptive unrest periods (days/decades) pose fundamental challenges to volcanic risk reduction. By contrast, the plumbing systems of young, immature stratovolcanoes are less complex, resulting in potentially less diverse eruption mechanisms and styles. However, due to their scarcity, young stratovolcanoes remain poorly understood.
This project will overcome this limitation by studying a young, persistently active stratovolcano (Bagana, Papua New Guinea) to catalogue its eruptive history and characterize the dynamics and timescales of magma assembly prior to eruptions. This unique dataset will be compared with a mature reference volcano (Etna, Italy; fieldwork optional) and with published data from other arc volcanoes.
The student will acquire high-resolution chemical maps of fresh volcanic rock samples using correlative multimodal imaging involving SEM, electron microprobe, and laser ablation time-of-flight mass spectrometry. These maps will capture the full complexity of the plumbing systems by combining textural analysis (to constrain magmatic processes[2]) with diffusion chronometry in zoned minerals (to retrieve pre-eruptive magmatic timescales[3]).
This work will give important insights into the evolution of stratovolcanoes and their plumbing systems and test whether their eruptive behaviour becomes more diverse over time. These results will be crucial for volcano monitoring and risk reduction efforts at subduction zone volcanoes worldwide.
Supervisors
You will also be supervised by organisations other than the University of Southampton, including:
