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The specific aims of the research project were:
- to determine the frequency and timing of major Arctic submarine slides;
- to better understand trigger factors and assess whether the frequency of the slides is likely to increase as climate changes and oceans warm;
- to assess the magnitude necessary for landslide-tsunamis to flood parts of the UK coast
- to quantify the likely cost to the UK of different types of inundation triggered by different types of landslide occurring in different locations.
The project used a range of techniques, including shipboard expeditions that mapped the Arctic seafloor and extract sediment cores from the seabed, fieldwork on land to identify and date coastal tsunami deposits, slope stability modelling, laboratory experiments showing how hydrate dissociation affects sediment strength, and modelling of future trends in seismicity. Also included is modelling of landslide motion, tsunami wave generation and propagation, and how tsunami waves would interact with existing UK coastal defence structures. Based on these results recommendations on measures that can be taken to offset a tsunami's impact on the UK coast can be given.Finally, a sensitivity analysis aima to capture uncertainties, and determine societal cost.
The science team worked closely with stakeholders, including government bodies (the Scottish Government and Defra, the Environment Agency) and the reinsurance sector.
National Oceanography Centre
Dr Peter Talling
Dr James Hunt
Dr Kevin Horsburgh
Dr Russell Wynn
Prof. Douglas Masson
British Geological Survey
Dr David Long
Prof. David Tappin
Dr Roger Musson
Dr Brian Baptie
University of Aberdeen
Dr Alastair Dawson
University of Dundee
Dr Sue Dawson
Dr Pedro Costa
University of Cambridge
Dr Julian Dowdeswell
University of Ulster
Prof. John McCloskey
Dr Suleyman Nalbant
Dr Paul Dunlop
University of Southampton
Dr Antonis Zervos
Dr Jeff Priest
Prof. Chris Clayton
University of Exeter
Prof. Peter Challenor
Imperial College
Dr Matthew Piggott
Dr Jon Hill
Dr Gareth Collins
Dr Peter Allison
Prof. Walter Distaso
University of Manchester
Prof. Peter Stansby
Dr Benedict Rogers
Dr Lee Cunningham
Outcomes:
Submarine landslaides can generate potentially very damaging and widespread tsunami. For example, the Storegga Slide that occurred 8,200 years ago offshore Norway is larger than Scotland. It produce a major tsunami that ran up to heights of up to 20m around surrounding coasts. A repeat of this scale of landslide-tsunami is one of the most damaging natural events that could impact the UK.
A first important result of our study is that an even larger landslide has been found below the Storegga Slide. This older event occurred at 55-60,000 years ago. Therefore, megalsides in this area have recurrence intervals of less than 100,000 years. This is important because events with recurrence intervals of less than 100,000 years should be considered on the UK National Risk Register, and in the design of nuclear power stations.
A second key result originates from dating the Traenadjupet and Nyk Slides located further along the Norwegian Margin, to the north of the Storegga Slide. It was previously thought that we would need another glacial advance to the shelf edge, to dump more sediment, and thereby cause a new landslide. However, our work on the Traenadjupet and Nyk Slides shows that they occurred within 15,000 years, without another ice stream advance. This shows that we do not need another ice stream advance to cause another large submarine slide from the same source area.
Finally, we show that the Traenadjupet Slide did not create a major tsunami along the nearest coastlines. This suggests that not all very large submarine slides are strongly tsunamigenic.
Nature Climate Change 3, 179 (2013) Waves on the Horizon – Interview with Peter Talling.