Storegga Slide

Storegga Slide
Name	Storegga Slide
Date	c. 8.2 ka BP
Location	Norwegian continental margin, Norwegian Sea
Type	Submarine landslide, tsunami
Fatalities	Unknown

Storegga Slide The Storegga Slide was a major submarine landslide off the Norway continental margin that triggered widespread tsunami waves affecting the North Sea, Atlantic Ocean and adjacent coasts during the early Holocene. It is central to studies in Quaternary, paleoclimatology, marine geology and geohazard assessment across Scotland, Norway, Iceland and Greenland.

Overview

The event occurred on the Norwegian Sea margin near the Shetland Islands and the Vøring Plateau, producing a collapse of sediment that affected the Faroe–Shetland Channel, North Atlantic Drift pathways and coastal sites from Scotland to Norway and Iceland. Research on the collapse integrates data from multibeam sonar surveys, seismic reflection profiles, radiocarbon dating and paleoceanography cores recovered by research vessels affiliated with institutions such as the Bergen Museum, University of Oslo, Scottish Association for Marine Science, Natural Environment Research Council and GEOMAR. The event has been invoked in discussions involving Doggerland inundation, Mesolithic coastal archaeology, Holocene climatic events, and interpretations by teams from Cambridge University, University of Edinburgh and University of Bergen.

Geological background

The continental margin involved rests on the Norwegian continental shelf and the Vøring Basin with sedimentary sequences deposited during deglaciation of the Scandinavian Ice Sheet, the British-Irish Ice Sheet and phases of Laurentide Ice Sheet retreat. Glacially derived sediments, glaciomarine drift, and contourite deposits accumulated under influence of the North Atlantic Current, Atlantic Meridional Overturning Circulation, and episodic iceberg calving from outlets like Skaftafell and Jostedalsbreen. Tectonic setting involves the legacy of Caledonian orogeny structures, Mid-Atlantic Ridge proximity, and basin subsidence related to post-glacial isostatic adjustment influenced by the Fennoscandian uplift. Studies use analogues from the Storegga Slide complex region and comparators such as the Nankai Trough, HUMBOLDT Slide and Grand Banks landslide.

Slide events and chronology

Multiple collapse phases have been identified using radiocarbon dating, optically stimulated luminescence and stratigraphic correlation with tephra layers including deposits linked to Hekla, Katla, and Grímsvötn eruptions. The main collapse is dated to about 8,200 radiocarbon years before present and correlates with the 8.2 kiloyear cold event recognised in Greenland ice cores such as GISP2 and GRIP. Seismic reflection and core datasets indicate an initial destabilisation episode followed by retrogressive failure fronts across the Storegga Fan and distal debris lobes on the floor of the Norwegian Sea, with activity imaged by institutions like BGS and Scripps Institution of Oceanography research cruises. Paleoceanographic markers tie collapse timing to meltwater pulses from the Stadial-interstadial transitions and drainage events linked to Proglacial Lake Agassiz discussions in North American contexts.

Tsunami generation and impacts

Numerical modelling using hydrodynamic codes developed at GEOMAR, University of Cambridge and NOAA combined bathymetry from GEBCO and multibeam grids to reconstruct tsunami propagation across the North Atlantic Ocean, impacting coasts of Scotland, Norway, Iceland and Faroe Islands. Geological tsunami deposits—laminated sands, boulder ridges, and marine microfossils—have been identified at sites including Shetland Isles, Vik in Iceland, Montrose Basin in Scotland and the Trøndelag coast, correlated with palaeotsunami horizons in cores dated alongside tephra from Hekla 3 and other eruptions. Consequences for human populations in Mesolithic Britain and hunter-gatherer communities near Doggerland have been inferred by archaeologists at University of York, University of Aberdeen and National Museums Scotland, though debate continues over the extent of societal disruption compared with contemporaneous sea-level rise recorded in Holocene sea-level curves.

Archaeological and paleoclimate evidence

Archaeological records including shell middens, lithic scatters and peat sequences in locations such as Orkney, Shetland, Fife and Sutherland show stratigraphic changes around the collapse horizon, while pollen records and macrofossil assemblages preserved in lacustrine sediments from Loch Lomond, Lough Neagh and Lake Suigetsu inform vegetation shifts associated with cooling linked to the 8.2 ka event seen in Greenland ice cores and D/H isotopic excursions. Interdisciplinary teams from Uppsala University, Trondheim, University of Copenhagen and Queen's University Belfast have correlated archaeological settlement patterns with tsunami deposits and abrupt climate markers, engaging debates also involving Vandals, Vikings-era analogues in public outreach despite temporal separation.

Monitoring and future hazard assessment

Contemporary monitoring employs networks including the European Tsunami Warning System, the Norwegian Meteorological Institute, NOAA National Weather Service, and seismic and geodetic arrays operated by Norwegian Seismic Array and Euro-Mediterranean Seismological Centre. Remote sensing from Sentinel satellites, repeat multibeam surveys by research vessels, and ocean-bottom seismometers maintained by OBS programmes contribute to slope stability models integrating scenarios published by IPCC-associated authors and hazard assessments from EMODnet and United Nations Office for Disaster Risk Reduction. Ongoing research at University of Bergen, GEOMAR, Lamont-Doherty Earth Observatory and Plymouth Marine Laboratory continues to refine probabilities of future large-margin collapses under influences of sea-level rise, changing thermohaline circulation and sediment supply from glacial systems.

Category:Geology Category:Tsunamis Category:Holocene