Project highlights

  • Investigate how edifice destruction impacts magma system evolution
  • Use a set of unique set of samples from Krakatau and Ritter to reconstruct volcanic records across different timescales
  • Explore fundamental controls on the temporal development of magma systems


Sector collapses are among the largest volume events to affect volcanic systems, and there is growing evidence that associated changes in surface loading can have profound effects on the stability of an underlying magma reservoir, manifested through shifts in eruption rate or composition and dominant eruptive behaviour. However, a detailed understanding of how magma systems are perturbed by destructive events is lacking, because of the challenges involved in generating high resolution reconstructions of past eruptive activity that span pre- and post-collapse periods. This project will take advantage of two unique datasets to address this problem: marine sediment samples collected offshore Ritter Island (Papua New Guinea) and samples related to the 2018 collapse of Anak Krakatau (Indonesia). There is the potential to add to these with further datasets to assess longer timescales, including material samples offshore Montserrat. These datasets preserve a record of activity before and after major collapses, and can advance our understanding of how volcanism at arc-volcanic systems responds to sudden changes in surface loading.

Ritter Island was the site of the largest historical sector collapse (around twice the size of the Mount St. Helens event in 1980), in 1888, and recent analysis of samples collected in 2016 indicates that unusually evolved magmas were erupted immediately following collapse, and that subsequent rebuilding of the submarine cone has produced rocks that are compositionally distinct from those erupted before collapse. The event provides an ideal opportunity to better understand the nature of post-collapse changes in activity. Additional samples will be collected on a planned research ship expedition in 2020. The recent devastating collapse of Anak Krakatau was smaller than that at Ritter, occurring on a young, basaltic volcano. Samples available from across the growth history of Anak, including post-collapse material, will allow a detailed petrological investigation of its evolution, testing results from Ritter.



University of Birmingham


  • Dynamic Earth


Project investigator

  •  Sebastian Watt (University of Birmingham



  • Victoria Smith; Michael Cassidy (University of Oxford)
  • Chiara Petrone (Natural History Museum)

How to apply


The project student would apply a range of sedimentological, geochemical and petrographic approaches to investigate volcaniclastic samples. Work will be undertaken at Birmingham (general stratigraphy, sediment properties, SEM imaging), Oxford (electron microprobe and laser ablation ICP-MS, analysing glass and mineral compositions) and the Natural History Museum (electron microprobe, diffusion chronometry).

The student will acquire evidence for changes in magma chemistry, mineral content, eruptive style and frequency in both pre- and post-collapse periods, and develop an eruptive chronology (particularly for the Montserrat core datasets) from existing age data, with the potential for additional 40Ar/39Ar dating. This will address whether and how the magmatic plumbing system that previously existed was affected and potentially reorganised following collapse. To develop this interpretation, the student will combine approaches including thermobarometry, textural analyses and diffusion chronometry, working with co-supervisors and facilities at the NHM and Oxford.

Training and skills

The student will receive training in core sampling, material preparation, sedimentological and geochemical analysis (optical microscopy, SEM analysis, electron probe micro-analysis) and techniques used to investigate and quantify magmatic processes (e.g., diffusion chronometry). The student will work with co-supervisors at facilities in the, with the potential to also gain experience with 40Ar/39Ar dating methods. The project thus provides the opportunity to obtain a wide range of analytical experience and work with varied facilities and several research groups, including work within a major cross-disciplinary international project.

Partners and collaboration

The project student will be based at Birmingham but would work closely with co-supervisors at Oxford and the Natural History Museum (a CENTA2 Level 1 partner), making use of laboratory facilities at a number of UK institutions. The student will also have the opportunity to build relationships with other international collaborators within these research projects (including in Indonesia and Papua New Guinea).

Further details

Please contact Dr Sebastian Watt –

This project will suit a student with an interest and facility for detailed laboratory work, an enthusiasm for volcanology and an interest in working within a collaborative, interdisciplinary project.

Applications need to be submitted via the University of Birmingham postgraduate portal,, by midnight 11.01.2021. Please first check whether the primary supervisor is within Geography, Earth and Environmental Sciences, or in Biosciences, and click on the corresponding PhD program on the application page.

This application should include

  • a brief cover letter, CV, and the contact details for at least two referees
  • a CENTA application form
  • the supervisor and title of the project you are applying for under the Research Information section of the application form.

Referee’s will be invited to submit their references once you submit your application, but we strongly encourage applicants to ensure referees are aware of your submission and expecting a reference request from us. Students are also encouraged to visit and explore the additional information available on the CENTA website.

Possible timeline

Year 1

Sedimentological analysis; production of stratigraphy; tephra sample preparation. Sampling and analysis of Ritter datasets. Attendance and presentation at a national volcanology conference.

Year 2

Geochemical and textural analyses; development of Ritter eruptive stratigraphy; development of growth history of Anak Krakatau; continuing geochemical analyses.


Year 3

Analysis of magmatic processes and plumbing system structure under pre- and post-collapse conditions, drawing on reconstructions across different timescales and between the different systems. Writing up of project results for publication; presentation at an international conference.

Further reading

Walter, TR, M Haghsehnas Haghighi, FM Schneider, D Coppola, M Motagh et al., 2019. Complex hazard cascade culminating in the Anak Krakatau sector collapse. Nature Communications 10, 4339.

Watt, SFL, J Karstens, A Micallef, C Berndt, M Urlaub et al., 2019. From catastrophic collapse to multi-phase deposition: flow transformation, seafloor interaction and triggered eruption following a volcanic-island landslide. Earth and Planetary Science Letters 517, 135–147.

Watt, SFL, PJ Talling, ME Vardy, DM Masson, TJ Henstock, V Hühnerbach, TA Minsull, M Urlaub, E Lebas, A Le Friant, C Berndt, GJ Crutchley, J Karstens, 2012.  Widespread and progressive seafloor-sediment failure following volcanic debris avalanche emplacement: landslide dynamics and timing offshore Montserrat, Lesser Antilles. Marine Geology, 323–325, 69–94.



This project does not require fieldwork or other international travel, so should be minimally impacted by any travel restrictions caused by the pandemic. Access to sample preparation and analysis facilities are the main requirements and are available through the institutions of the supervisory team, within the UK. These facilities are currently open and interruptions to this project are therefore not foreseen in the medium term.