Volcanological history of the last 1000 years of Soufrière, St Vincent Eastern Caribbean:
Eruption mechanisms and hazards
Director of Studies: Dr Paul Cole
Other supervisors: Arjan Dijkstra, Prof Jenni Barclay (UEA), Dr Richard Robertson (University of the West
Indies)
Applications are invited for a three-year PhD studentship. The studentship is expected to
commence on the 1st October 2015 or 1st January 2016.
Project Description
Soufrière volcano on the island of St Vincent is one of the most active volcanoes in the Eastern Caribbean (1). It
has had four significant explosive eruptions in historical time: in 1979, 1902, 1812, and 1718. These eruptions
generated ash fallout, which affected both the island of St Vincent and regionally large areas of the Caribbean,
as well as forming hazardous pyroclastic density currents (PDCs) on the volcanoes flanks which directly
resulted in the deaths of a total of 1600 people (2).
Today 20,000 people live around the immediate flanks of the volcano and are at direct threat from future
volcanic activity. Soufrière is also a ‘trial’ volcano of the STREVA (Strengthening Resilience in volcanic Areas)
NERC/ESRC research consortium and is the focus of multidisciplinary research in understanding volcanic
hazard and risk.
Historical eruptions have been shortlived, generally lasting days to weeks, but violent, generating PDCs that
travel largely down valleys, whereas hazardous high-velocity PDCs are more widespread and can overtop ridges
(3)
. Thus constraining the spatial extent of the products of these eruptions and documenting their character
provides important information on the potential hazard of future events. Several historical events have typically
been associated with apparent hydrovolcanic activity (4), crater lakes are a typical feature but the role of external
water in explosive activity has yet to be constrained. Therefore investigations into the detailed mechanisms of
these eruptions are critical to understand the true nature of these events.
The historical eruptions define a weak cyclicity of hazardous explosive eruptions occurring every 80 to 100 years.
Moreover recent radiometric dating (by the DoS) has established that this cyclicity continues into prehistory with
a significant, particularly large, explosive eruption occurring around 1600 CE. Radiocarbon dates indicate that
several other events between 500 and 1000 yBP also occurred (1). Further constraining the cyclicity of the
volcano is paramount in understanding the likelihood and therefore the probability of future activity.
Although the composition of Soufrière magmas are largely basaltic andesite (5) (and are relatively primitive), the
geochemistry (and any within event variation) of many specific eruptions has not been constrained. Samples
already collected demonstrate clear evidence for magma mingling and possibly mixing, providing information on
potential eruption triggers. Studying the compositional trend both within and between eruptive events will provide
information on magma recharge augmenting information on the nature of eruptive cyclicity and how this links to
the magma plumbing system. Furthermore, abundant cumulate nodules available for petrological study will
provide a direct window into the processes in the deeper part of the plumbing system/magma chambers of the
volcano. Therefore the aim of this studentship is to understand the nature of eruptions that took place at
Soufriere St Vincent over the last 1000 years or so, from a volcanological and petrological point of view.
In order to achieve this aim the student will undertake:
• Fieldwork on the island of St Vincent to document both historic and pre-historic most recent eruptive
products of Soufriere volcano (DoS already has undertaken several weeks of fieldwork and has a suite
of samples) to establish the nature and composition eruption products at Soufriere St Vincent
(supervision provided).
• Laboratory work on the grainsize and component analysis of the tephras generated to investigate the
nature and emplacement mechanisms involved in the products of these explosive eruptions (training
provided).
•
•
XRF and SEM at Plymouth University to analyse the petrology and geochemical variation of the juvenile
magma involved in both individual events. (training will be provided)
Radiocarbon dating to further the understanding on the periodicity of Soufriere St Vincent in the last
1000 years (dependent on separate funding application).
The crater of Soufrière St Vincent, with the Lava dome formed at the end of the eruption in 1979
Other Support
Understanding the periodicity of activity of Soufrière volcano over the last 1000 years is an important objective of
this work. The student will be expected to submit a proposal (NCRF) to undertake radiocarbon dating of the
products of prehistoric eruptions.
References
(1) Simkin T, Siebert L and Kimberly P (2011) Volcanoes of the World. Third Edition. Geoscience Press.
(2) Robertson REA., (1995) An assessment of the risk from future eruptions of the Soufriere volcano of St Vincent,
West Indies. Natural Hazards 11(2):163-91
(3) Cole PD., Neri A, and Baxter P, (2015) Hazards from Pyroclastic Density Currents. In Encyclopaedia of Volcanoes.
nd
2 Edition. Elsevier
(4) Robertson (2005) St Vincent. In Volcanic Hazard Atlas of the Lesser Antilles. Ed by Lindsay JM, Robertson REA.,
Shepherd JB, Ali S.
(5) Heath E, Macdonald R, Belkin H, Hawkesworth C, Sigurdsson H 1998 Magma genesis at Soufriere, Lesser Antilles
Arc. Journal of Petrology 39, No10 1721-1764
Eligibility
Applicants should have (at least) a first or upper second class honours degree in Earth Sciences (or a related
subject) or equivalent qualification. Desirable requirements: an MSc or MRes. The studentship is supported for 3
years and includes full Home/EU tuition fees plus a stipend of £14,057 per annum. The studentship will only fully
fund those applicants who are eligible for Home/EU fees with relevant qualifications. Applicants normally
required to cover overseas fees will have to cover the difference between the Home/EU and the overseas tuition
fee rates (approximately £10,800 per annum). If you wish to discuss this project further informally, please contact the director of studies (Dr Paul Cole: email:
[email protected]). However, applications must be made in accordance with the details shown below.
You can apply via the online application form which can be found at:
https://www.plymouth.ac.uk/study/postgraduate and click ‘Apply’.
Please mark it FAO Sharon Healy and clearly state that you are applying for a PhD studentship within the
School of Geography, Earth and Environmental Sciences and clearly state which project you are applying for.
General information about applying for a research degree at Plymouth University For more information on the admissions process contact Sharon Healy ([email protected]).
The closing date for applications is 17:00 on 15th September 2015. Shortlisted candidates will be invited for
interview. We regret that we may not be able to respond to all applications.