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Department of Geography

Staff Profile

Professor Ian Shennan

Professor in the Department of Geography
Telephone: +44 (0) 191 33 41934
Fax: +44 (0) 191 33 41801
Room number: S203

Contact Professor Ian Shennan (email at ian.shennan@durham.ac.uk)

Biography

I have a long association with the Department, BSc 1976, PhD 1991, Chair of the Board of Studies 1997-2000. My main areas of research focus on sea-level and environmental changes and I set up the Sea Level Research Unit in 1987, attracting more than 30 research grants and contracts worth more than £2 million.

Current research areas are:

  • Late-Quaternary Sea-Level And Environmental Changes In The North Sea Region
  • Land Uplift And Subsidence In The United Kingdom And North Sea Region
  • Global Meltwater Discharge Since The Last Glacial Maximum
  • Earthquake Hazards in Alaska, Washington and Oregon, USA

Land uplift and subsidence In Britain and Ireland

This work started in the 1980s, with first paper, published 1987, quantifying the regional-scale pattern of uplift and subsidence around the North Sea. This was followed, in 1989, Journal of Quaternary Science, by the first analysis for 35 years to provide a quantitative estimate of current land uplift and subsidence in mainland Great Britain to be supported by the geological and oceanographic data. Significant advances in data quality and spatial cover followed over the next 10 years, with a revised analysis (Shennan & Horton, 2002) that included tidal range changes and anthropogenic-induced subsidence. Further consideration of sediment compaction and integration of field data with geophysical models led to the most recent updates, Shennan et al 2006 and 2009. These provide our most reliable measures of the long term rate of relative land/sea-level change in Britain and Ireland, prior to any 20th century increase in sea level. To use this map alongside any predictions of future global sea level rise you must add the prediction (for example, from the latest IPCC report) to the value for a chosen location. If your location includes areas of soft sediments, such as coastal lowlands or reclaimed esturine sites, you must also add the effect of sediment compaction to get the total amount of land subsidence.

The image is available here, the full paper/article is available from GSA Today: http://www.geosociety.org/gsatoday/archive/19/9/article/i1052-5173-19-9-52.htm “Late Holocene relative land- and sea-level changes: Providing information for stakeholders”. Authors: Ian Shennan, Sea Level Research Unit, Department of Geography, Durham University, Durham DH1 3LE, UK; Glenn Milne, Department of Earth Sciences, University of Ottawa, Ottawa, K1N 6N5, Canada and Sarah Bradley, Department of Earth Sciences, Durham University, Durham, DH1 3LE.


Photograph 1: Loch nan Corr, Kintail, Scotland. Taking sediment cores from what is now the freshwater loch to measure land uplift. It was previously a marine embayment, but gradual land uplift has raised it above the level of even the highest tides.

Photograph 2: Ancient forest and peat layers at Druridge Bay - shows how relative sea-level has risen in comparison to the land, even where the land is still rising, its just that sea level has risen even faster as the ice sheets melted.

Late-Quaternary Sea-Level and Environmental Changes in the North Sea Region

This involves application of a wide range of methods of palaeo-environmental reconstruction (field, laboratory, experimental and analytical techniques) and development of a new research methodology.

  • First developed during the work on the Fenlands and subsequently applied in many other areas the “sea-level tendency” methodology enables analysis and correlation of diverse evidence of relative sea-level changes and coastal evolution.
  • New research in NW Scotland, including development of methods new to the UK, is revising our understanding of sea-level change and crustal deformation at the regional scale. The resulting 16000 year record of relative sea-level change in NW Scotland is one of the longest and most detailed available in the world and is very important in constraining models of earth rheology and glacial history since the Last Glacial Maximum.
  • Integrating quantitative models of glacio-hydro-isostatic models with tide models to produce simulations of the Holocene changes in coastlines, bathymetry and tides in the North Sea.
  • Modelling of tidal range changes during the Holocene, implications for reconstructing sea-level changes and sediment movement.

Global Meltwater Discharge Since the Last Glacial Maximum

The 16000 year record of relative sea-level change (RSL) in NW Scotland allows calculation of quantitative limits of global meltwater discharge in terms of both timing and magnitude (see recent publications). Various claims in the literature about periods of rapid ice decay and subsequent climate changes can be readily tested by such RSL records. In order to remove any effects of local ice sheet chronology my current research in this area focuses upon establishing a better spatial coverage, to create similarly comprehensive records for 3 areas in Scotland. This will be a powerful discriminator between the different model solutions and hence the timing and source of meltwater discharge.

Earthquake and Tsunami Hazards in Alaska, Washington and, Oregon

This applied aspect of sea-level research utilises theory and methods of analysis developed at Durham to the identification and analysis of great earthquakes in plate-boundary locations, with recent projects focussed upon Washington, Oregon and Alaska.

  • Application of microfossil techniques to differentiate between seismic and non-seismic relative land/sea-level movements
  • Development and application of quantitative methods to estimate relative land/sea-level changes throughout multiple Holocene earthquake deformation cycles
  • Verification of methods against observations from the 1964 Alaska Earthquake (Magnitude 9.2)
  • Identification of pre-seismic relative sea-level rise prior to the 1964 Alaska Earthquake and other late Holocene great earthquakes in Alaska
  • Ongoing research focuses upon whether pre-seismic relative sea-level rise represents a pre-cursor to great earthquakes
  • Variation in the locations and size of earthquake rupture zones, fault segmentation and long-term mountain building
  • Evidence for tsunamis associated with great earthquakes


Photograph 1: Sediment section exposed at the top of the present storm beach of ‘The Forgotten Coast’ of Alaska, east of Cape Yakataga. The boulders are those found at the upper limit of the modern beach. Immediately behind the boulders the sea has eroded into sediments, forming a small cliff, and exposing different sediment layers of peat, mud and sand. Ron Bruhn, University of Utah, stands on the top of the section.

Photograph 2: Close up of the sediment section in photograph 1. This part of the section is the horizontal boundary between two layers of sediment, about 1m above the boulders in photograph 1. The scale arrow is 10cm total, the lower part of the arrow shows 1cm increments. The wavy line in the top part of the image is simply where we have cleaned the sediment surface to expose the uncontaminated sediment, free from soil that has fallen down the cliff. The sharp, horizontal boundary, represent a change from beach sand (light brown, coarse texture) to grey mud. Fossils in the mud and radiocarbon dating show it to be sediment laid down in a lagoon or shallow lake approximately 1500 years ago. So, the scientific interpretation is that an earthquake caused uplift of at least 2m, instantaneously raising a beach environment to above high tide level, allowing a freshwater lagoon or shallow lake to develop.

Photograph 3: A view of Mt. St Elias and Icy Bay. The area encompasses part of the Wrangell - Saint Elias National Park and Mt. Saint Elias rises from tidewater to an elevation in excess of 5400m and the region is marked by North America's greatest alpine and piedmont glaciers. This spectacular region is an enigma in the study of plate tectonics and great earthquakes because of structural complexity in the transition from strike-slip to subduction plate boundaries, and its remoteness.

Photograph 4: Aerial view from the helicopter of the Forgotten Coast, Alaska, showing linear patterns caused by different tree growth, grasses and swamp vegetation communities. These vegetation differences reflect the underlying soil, trees growing on the more sandy ridges. The ridges and hollows reflect old beach ridges and sand dune, uplifted above sea level during great earthquakes.

Research Groups

Research Projects

Research Interests

  • Earthquake hazards
  • Impacts of future sea-level rise
  • Land uplift and subsidence
  • Late quaternary sea-level and environmental changes
  • Remote sensing applications in coastal change

Selected Publications

Journal Article

Chapter in book

  • Shennan, Ian Sea level studies: Overview. In: Reference Module in Earth Systems and Environmental Sciences. Elsevier; 2018.
  • Shennan, I. Handbook of sea-level research: framing research questions. In: Shennan, I., Long, A.J. & Horton, B.P. Handbook of Sea-Level Research. Hoboken, NJ: John Wiley; 2015:3-25.
  • Shennan, I. & Hamilton, S.L. Holocene sea-level changes and earthquakes around Bering Glacier. In: Bering Glacier: Interdisciplinary studies of Earth’s largest temperate surging glacier. Geological Society of America; 2009.
  • Shennan, I., Barlow, N. & Combellick, R. Palaeoseismological records of multiple great earthquakes in south-central Alaska - a 4000 year record at Girdwood. In: Active tectonics and seismic potential of Alaska. American Geophysical Union; 2008:185-199.
  • Shennan, I., Barlow, N.L.M. & Combellick, R. Palaeoseismological records of multiple great earthquakes in south-central Alaska: a 4000 year record at Girdwood. In: Freymueller, J.T. Haeussler, P.J. Wesson, R.L. & Ekstrom, G. Active tectonics and seismic potential of Alaska. Washington, DC: AGU Geophysical Monograph Series; 2008:185-199.
  • Shennan, I. Encyclopedia of Quaternary Science. In: Elsevier; 2007:2967-2974.
  • I. Shennan & S. Woodroffe Holocene sea level changes around Loch Duich and Loch Alsh, Northwest Highlands. In: R.M. Tipping The Quaternary of Glen Affric and Kintail. Quaternary Research Association; 2003:123-124.
  • S.L. Hamilton & I. Shennan Pre-seismic land and sea-level movements and great Holocene earthquakes, Alaska. In: Coastal Environmental Change During Sea Level Highstands: A Global Synthesis with Implications for Management of Further Coastal Change. IGCP Project 437 International Meeting; 2002:38.
  • Shennan, I., Lambeck, K., Flather, R., Wingfield, R., Horton, B.P., McArthur, J.J., Innes, J.B., Lloyd, J.M. & Rutherford, M.M. Modelling western North Sea palaeogeographies and tidal changes during the Holocene. In: Shennan, I. & Andrews, J.E. Holocene land ocean interactions and environmental change around the North Sea. London: The Geological Society; 2000:299-319.
  • Long, A.J., Innes, J.B., Shennan, I. & Tooley, M.J. Coastal stratigraphy: a case study from Johns River, Washington. In: Jones, A.P., Tucker, M.E. & Hart, J.K. The description and analysis of Quaternary stratigraphic field sections. Quaternary Research Association Technical Guide 7, Quarternary Research Association; 1999:267-286.

Edited book

Other (Digital/Visual Media)

Report

Show all publications

Media Contacts

Available for media contact about:

  • Seas & rivers: sea-level changes
  • Seas & rivers: coastline & environmental change
  • Regional landscape & environment: sea-level changes
  • Regional landscape & environment: coastline and environmental change
  • The Earth: Rocks & natural forces: sea-level changes
  • The Earth: Rocks & natural forces: coastline & environmental change

Selected Grants

  • 2013: Late Holocene paleoseismology of the Kenai Peninsula and Kachemak Bay region, Alaska and implications for plate segmentation (£46874.21 from U S Geological Survey)
  • 2012: Late holocene earthequakes in Kodia Island, Alaska and implications for plate segmantation (£46480.91 from U S Geological Survey)
  • 2010: Sediment signatures of the 2010 Chile Mw 8.8 earthquake (£51729.21 from NERC - Natural Environment Research Council)
  • 2010: Spatial and temporal patterns of deformation associated with multiple late holocen earthquake in Kodiak Island (£48333.83 from U S Geological Survey)
  • 2009: Geological Society of America Annual Meeting 2009 (£1200.00 from The Royal Society)
  • 2009: Spatial and temporal patterns of deformation associated with multiple late holocen earthquake in Alaska (£49048.41 from US Geological Survey)
  • 2008: NORTH WEST COAST RAPID COASTAL ZONE (£7000.01 from Archaeological Research Services Ltd)
  • 2007: NORTH EAST COAST RAPID COASTAL ZONE (£5500.01 from Archaeological Research Services Ltd)
  • 2006: NORTH TO ALASKA: GEOSCIENCE (£1152.00 from The Royal Society)
  • 2006: RECURRENT HOLOCENE PALEOSEISMICITY (£35183.74 from US Geological Survey)
  • 2003: RECURRENT HOLOCENE PALAEOSEISMICITY (£50054.72 from US Geological Survey)
  • 2002: LATE HOLOCENE PALEOSEISMICITY (£54900.00 from US Geological Survey)
  • 2001: A830 DEVELOPMENT ARISAIG-KINSADEL (£25720.00 from The Highland Council)
  • 1999: PALAEOENVIRONMENTAL CORE SAMPLING (£12000.00 from Tyne & Wear Museums)
  • 1997: NORTHERN PLAIN (£32834.00 from Centre for Manx Studies)
  • 1994: BERWICK TO NORTH NORFOLK (£214058.00 from NERC - Natural Environment Research Council)
  • 1994: HUMBER ESTUARY (£92820.00 from NERC - Natural Environment Research Council)
  • 1994: MODELLING HOLOCENE (£188494.00 from NERC - Natural Environment Research Council)
  • 0: HUMBER GEOMORPHOLOGY (£10000.00 from Binnie Veatch)

Supervises