Global LAhar Model

 

Supervisors: Dr Vern Manville (SEE), Professor Nigel Mountney (SEE), Dr Jonathan Carrivick (SoG)

Contact email: v.r.manville@leeds.ac.uk

 

A PhD studentship to be run under the auspices of the NERC Panorama DTP in the School of Earth and Environment at the University of Leeds

Summary

This project seeks to improve our understanding of the controls on the initiation, propagation, and impacts of lahars and other volcano-hydrologic hazards. It will achieve this by analysing both the geomorphological and sedimentary impacts of past and modern events, and testing the importance of key lahar parameters through modelling. The major project deliverables will constitute both fundamental science advances and also applied science tools; for example to enable predictions of post-eruption landscape changes and recovery, and for the forecasting and mitigation of hazards, respectively. Project outputs will specifically be of direct relevance to modellers running numerical simulations of lahar behaviour and emergency response managers. Key parts of this project include:

• Compilation of a database of lahar events around the world.
• Potential for fieldwork to gather supplementary data.
• Numerical modelling of lahar behaviour to test the utility of the database in lahar parameterization.
• Joining an integrated research group, with linkage to international research associates and industry.
• Attending international conferences in Europe, the US and elsewhere.
• Opportunities for career development across academia, internships, industry and beyond.

Background

Lahars are defined as ‘sediment-laden flows of water and rock debris, other than normal streamflow, from a volcano’. They are complex, multiphase geophysical flow phenomena. Lahars can be triggered by a range of mechanisms, including primary or eruption-triggered events initiated by explosive expulsion of crater lake water or the rapid melting of summit snow and ice by pyroclastic flows, and secondary lahars that can be generated by heavy rainfall on fresh unconsolidated tephra and pyroclastic density current deposits. Globally, since 1783 A.D. lahars have been the third most lethal volcanic hazard, often devastating areas beyond the range of direct volcanic hazards and persisting for years or decades after the initial volcanic activity.

Despite recent advances in the characterisation of volcano-hydrologic hazards, derived from a small number of well-studied events, we lack a comprehensive and qualitative understanding of the influence of key hydraulic parameters on their initiation and downstream propagation and evolution. This creates problems for numerical modellers and emergency managers seeking to forecast the likely severity and duration of lahar hazards that may be associated with a period of volcanic unrest or escalating eruptive activity. Key questions include: what will be the magnitude of the lahars, how much will they increase their volume by, how fast will they travel, what areas will they inundate, how long will they persist after the eruption is over. Current understanding is qualitative, and typically scenario-based, using predictions rooted in past activity at a volcano. Unlike other volcanic phenomenon, such as large explosive volcanic eruptions (LaMEVE), volcanic dome eruptions (DomeHaz) and debris avalanches, no equivalent database exists for lahars and similar phenomenon meaning that limited readily accessible quantitative information is available for modellers and emergency managers to use to inform their simulations and decisions.

Aim and objectives

The overall aim of this PhD project is to improve our understanding of the controls on lahar initiation, propagation and consequences. This will be achieved through compilation of a database of lahar events, capturing key parameters on triggering mechanisms, flow behaviour, and their sedimentary and geomorphic impacts, including their evolution through space and time. Lahars and related volcano-hydrologic hazards are complex phenomenon, permitting multiple lines of investigation whose balance can be tailored to the specific interests of the appointed research student.

Specific research objectives are as follows: (i) to compile a comprehensive database of lahar events globally from published resources (and possibly field-based data gathering); (ii) to quantify resistance factors for different types and styles of lahar according to generating mechanism, magnitude and channel geometry to generate outputs that serve as predictive tools and as guides to model parameterisation; and (iii) to demonstrate the applied benefits of the research through numerical modelling of well-characterised case studies. It is expected that each objective will form the core of a journal publication/chapter for thesis by publication.

Methodology

The research will integrate results from several of the following study approaches: (i) meta-analysis of published literature datasets on historical lahar events from volcanoes around the world; (ii) data acquisition from remote-sensing datasets (satellite images, LiDAR data) of several recent lahar events (including the possibility of fieldwork), conducted with consideration of river and catchment characteristics (hydrology, climate, vegetation, etc.); (iii) compilation of a database using material obtained from (i) and (ii); and (iv) numerical modelling of well-characterised lahar events to test the accuracy of parameterisation from the database. The appointed research student will be able to focus on study methods of interest to them.

As part of the project, there will be scope for assessing the value of the fundamental findings for predictive purposes, in the context of natural hazards forecasting and mitigation.

Potential for high-impact outcome

A major deliverable of this project will be a database of key hydraulic parameters for lahar simulation under a range of scenarios, which will enable modellers and responding agencies to more rapidly and accurately predict the impacts of future volcanic eruptions. NERC has a proven track record of supporting the compilation of similar databases for volcanic phenomenon.

The appointed candidate will be expected to publish the results of their research in leading pure and applied research journals such as Nature Geoscience, Geology, Journal of Volcanology and Geothermal Research, Bulletin of Volcanology, Natural Hazards and Earth Systems Science etc. The project supervisors each have long track histories of internationally recognized research publications in volcano-hydrologic hazards and landscape responses to explosive volcanism, geological databases, and numerical simulation of flood events.

Eligibility

Applicants should have a BSc degree (or equivalent) in geology, geology-geography, geography, earth sciences, geophysics or a similar discipline. An MSc or MGeol in geoscience (or similar) is desirable. Experience of using GIS software would be useful, though is not essential.

Training

Training will be provided in advanced concepts and techniques in fluvial hydrology and volcanic processes, volcaniclastic sedimentology, and GIS. The nature of this research project will enable the appointed applicant to consider a future career in either academia or industry. As the PhD project straddles the boundary between disciplines, the successful applicant will join both the Sedimentology Group and the Volcanology Group, each comprising teams of 30+ academic staff, PDRAs and PhD research students, which are based at Leeds but additionally benefit from a world-wide network of research associates.

CASE Partner

N/A