Changing how the world works - Investigating volcanic sector collapse in Indonesia

Third-year PhD Earth Sciences student Kerys is determined to contribute to Volcanology and Earth Sciences by investigating how magmatic systems are perturbed by volcanic sector collapse at ocean island volcanoes.

Volcanoes globally form incredibly diverse and dynamic systems with the potential to generate devastating hazards. As urban areas rapidly expand, the number of communities exposed to volcanic risk continues to grow, and so does our need for effective hazard management. Continually improving our understanding of these hazards is key to successful monitoring and mitigation, and ultimately, was the driver behind me pursuing a PhD in Volcanology.

More specifically, my research interests center around volcanic collapses and their deposits – in the future I’m hoping to expand this into the submarine realm. Before continuing with this post, I want to take a moment to explain what is meant by the term volcanic sector collapse…

Volcanic sector collapses are a type of catastrophic mass movement, involving the rapid removal of material away from a volcano. These events share many similarities with other volcanic landslides, but occur on significantly larger scales, accounting for more than 10% of the volcano’s total volume. In many examples the failure cuts deeply into the slope, drastically modifying a volcano’s morphology.

My research focuses on the volcano of Anak Krakatau, a relatively small but highly active volcanic island located between Sumatra and Java in Indonesia. In December 2018 it underwent a substantial failure of its south-western slope, reducing the island’s height by around 200 m and surface area by approximately half. This triggered a devastating tsunami, inundating the coastlines of the surrounding Sunda Strait and resulting in significant loss of life and damage to infrastructure.

What makes Anak Krakatau’s case so unique is that most historical sector collapses have occurred on much larger structures, constructed over timescales of several thousands of years. In contrast, this failure occurred just 91 years after the volcano first emerged above sea-level. It’s this young age which has meant that the volcano’s history has been exceptionally well-preserved, both in archival documents such as reports, photos and maps, but also within the rock record. Combined, these all capture a complete cycle of construction, failure and subsequent regrowth in detail, enabling the rare opportunity to explore the relationship between volcano growth, eruption style and instability on a much shorter timescale. This not only provides an analogue for understanding these cycles at other volcanoes globally, but is also key to understanding more about Anak Krakatau’s future. This is particularly critical in developing improved hazard management strategies in such a densely populated region.

This research also forms part of an important ongoing international collaboration between the Indonesian National Research and Innovation Agency (BRIN), Bandung Institute of Technology (ITB) and the University of Birmingham. With the support of these international colleagues, I was able to visit Anak Krakatau last summer, where we worked together to sample historic volcanic ash and conduct an updated drone survey of the volcano.

Prior to my PhD, I studied MSci Geology and Physical Geography here at the University of Birmingham. My final-year research project involved analysing volcaniclastic material captured within sediment cores from the Mexico City region, testing the evidence for or against a volcanic sector collapse emplacement mechanism. This project is where I really discovered my interest in volcanism and its impacts on life. 

After graduating, I went on to work as part of a widening participation organisation, aiming to help young people make more informed decisions about their future higher education and career pathways. Whilst working with local schools was incredibly rewarding, it made me realise how much I missed research and working in the field, leading me to return to academia where I find myself today!  

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