The School of Geography, Politics and Sociology

Staff Profile

Dr Stuart Dunning

Senior Lecturer in Physical Geography

Background

Interests

Keywords: Landslides; magnitude-frequency; paraglacial; geomorphology

I am a quantitative physical geographer researching hillslope processes and their magnitude-frequency, often in cryospheric systems undergoing rapid change. I have a speciality in large rock-avalanches, with a focus on their dispersion through glacial and fluvial reworking which serves to reduce our knowledge of their erosive work, and, to underestimate their hazard.














Research

Current Projects

1. Landslides triggered by Storm Desmond at the A83, Rest and Be Thankful, Scotland (NERC Urgency, £47k)

Storm Desmond produced intense and prolonged rainfall which resulted in extensive flooding in the U.K. A number of landslides were also triggered, many of which damaged infrastructure and the transport network in particular. We are in a unique position, holding pre-event, and during event data for slopes that failed during and after Storm Desmond  at the most 'at risk' trunk road in Scotland1-3, the A83 Rest and Be Thankful (RABT), Argyll and Bute, which is a key arterial route. Since 2007 at least 13 debris flows have occurred. Existing monitoring has been invaluable in defining post-event conditions and sediment dynamics with instruments often installed after events, but there are no complete (pre- and post-) data on a single large event. This is essential in refining and validating physical and numerical modelling approaches, which can be used for enhanced management of the problem, and the design/refinement of appropriate monitoring and mitigation strategies that our project partners are responsible for putting into operation. Our proposal is to collect transient post-event data to allow follow-on funding proposals to answer the outstanding science questions, which are relevant for multiple sites beyond the RABT, and to document the transience of key evidence to inform how 'urgently' we do need respond to future large events to adequately quantify them.

2. A new approach to West Antarctic Ice Sheet evolution using blue-ice moraines on nunataks.

Did the West Antarctic Ice Sheet (WAIS) survive the last interglacial? We propose to use nunataks as dipsticks of ice-sheet elevation change to help answer this question. There are currently two conflicting hypotheses:  

Hypothesis 1: A dynamic WAIS. The hypothesis is that the WAIS disappeared under last-interglacial conditions ~125,000 years ago when climatic and oceanic conditions were slightly warmer than those of the present day.

Hypothesis 2: A stable WAIS. The WAIS may have varied in elevation but that it persisted as a coherent ice sheet during the last interglacial.  

The co-existence of two opposing hypotheses implies that we have much to learn about the principal controls on ice-sheet stability. This uncertainty undermines confidence in our ability to predict the future of the WAIS and its effect on global sea-level change. Important research on the WAIS relies on satellite observations which monitor changes in velocity and elevation over recent decades, while predictions of future changes rely on ice-sheet models. Both approaches would be enhanced if we knew what happened to the WAIS during the last glacial cycle. The longer term perspective tells of the trajectory of change upon which decadal changes are superimposed. Further, a history of elevation changes during a glacial cycle provides data with which to constrain and improve ice-sheet models.  

This project is testing the two hypotheses using moraines that form on nunataks in blue-ice areas. Blue-ice areas result from strong downslope winds which are often funnelled in the vicinity of nunataks and ablate the ice surface. In response the ice flows into such ablation areas, sometimes bringing basal debris to the surface which is then deposited at the ice margin. Relict moraines occur on certain nunatak slopes above the present ice surfaces and are over 400,000 years old, suggesting that there is the potential to obtain a long record of ice elevation change.  

This project brings together glaciologists, geomorphologists and geophysicists to work in the Heritage Range, a group of nunataks which protrude through the central WAIS dome. We will test predictions of the two competing hypotheses firstly by examining the processes of blue-ice moraine formation today using field survey and radar, and secondly by establishing the form and sediment characteristics of the moraines and their age. The latter will employ exposure-age dating, a technique that measures the time a rock has been at the surface and exposed to cosmic rays. By using more than one isotope we can establish times when a rock surface may have been buried by ice and thus there is the potential to reconstruct a rich history of ice elevation changes. In this way we will assess if the WAIS remained intact, or disappeared during the last interglacial. Our hope is that the approach could be extended to other nunataks in Antarctica and provide widely dispersed evidence of elevation changes in predicting the future response of the WAIS to a changing climate.

NERC Standard Grant (February 2012 – July 2015). Sugden, D., Woodward, J., Dunning, S., Fogwill, C. £557,733.00 (Northumbria £148,480.34) NE/I025840/1

Publications