earth science

Storegga Slide

Storegga Slide is a earth science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Storegga Slide rather than just read about it. In short: The three Storegga Slides (Norwegian: Storeggaraset) are amongst the largest known submarine landslides. They occurred at the edge of Norway's continental shelf in the Norwegian Sea, approximately 6225–6170 BCE.

Key takeaways

Storegga Slide belongs to earth science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Storegga Slide to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Storegga Slide from memory before moving on to harder problems.

Reference excerpt

The three Storegga Slides (Norwegian: Storeggaraset) are amongst the largest known submarine landslides. They occurred at the edge of Norway's continental shelf in the Norwegian Sea, approximately 6225–6170 BCE. The collapse involved an estimated 290 km (180 mi) length of coastal shelf, with a total volume of 3,500 km3 (840 cu mi) of debris, which caused a paleotsunami in the North Atlantic Ocean.

Description

Storegga (Norwegian: 'Great Edge') is located at the edge of Norway's continental shelf in the Norwegian Sea, 100 km (62 mi) north-west of the Møre coast. In around 6200 BCE, structural failures of the shelf caused three underwater landslides, which triggered very large tsunamis in the North Atlantic Ocean. The collapses involved an estimated 290 km (180 mi) length of coastal shelf, with a total volume of 3,500 km3 (840 cu mi) of debris. Based on carbon dating of plant material recovered from sediment deposited by the tsunamis, the latest incident occurred around 6225–6170 BCE. In Scotland, traces of the subsequent tsunami have been recorded, with deposited sediment being discovered in Montrose Basin and the Firth of Forth up to 29 km (18 mi) inland and 4 m (13 ft) above current normal tide levels.

Possible mechanism The triggering mechanism is thought to have been an earthquake that induced a catastrophic expansion of methane clathrate, a solid compound consisting of large amounts of methane suspended within a crystal water structure that forms in deep oceans under extremely high pressure. If removed from a high-pressure, low-temperature environment, one cubic metre of solid methane clathrate expands to 164 cubic metres of gaseous methane. If such an expansion occurred, it may have weakened the integrity of the surrounding rock sufficiently to trigger the slide. A second theory states that over time, streams from melting glaciers had carried trillions of tons of sediment to the edge of the continental shelf, where it accumulated in many layers. In this case, a trigger such as an earthquake could have caused a large area of seafloor to collapse into the deep Norwegian sea, thus carrying the enormous volume of accumulated sediment along with it.

Impact on human populations

At, or shortly before, the time of the Second Storegga Slide, a land bridge known to archaeologists and geologists as Doggerland linked Britain, Denmark and the Netherlands across what is now the southern North Sea. This area is believed to have included a coastline of lagoons, marshes, mudflats and beaches, and to have been a rich hunting, fowling and fishing ground populated by Mesolithic human cultures. Although Doggerland was permanently submerged through a gradual rise in sea level, it has been hypothesized that coastal areas of both Britain and mainland Europe, extending over areas which are now submerged, would have been temporarily inundated by a tsunami triggered by the Storegga Slide. This event would have had a catastrophic impact on the Mesolithic population at the time. It is estimated that up to a quarter of the Mesolithic population of Britain was killed. A 2021 study found that about 600 km (370 miles) of Scotland's northern and eastern coastline were affected, with water encroaching 29 km (18 miles) inland. With present-day populations and sea levels, a similar event today could devastate and destroy seafront and port areas of Arbroath, Stonehaven, Aberdeen, Inverness, Wick, and Montrose. While the tsunami caused by the Second Storegga Slide would have been devastating for those within the run-in zone, ultimately the tsunami was neither universally catastrophic nor the reason behind the inundation of the last vestiges of Doggerland.

Future slides Storegga has been thoroughly investigated as part of the preparation activities for the Ormen Lange gas field off the coast of Norway. The prevalent conclusion is that the slide was caused by glacial deposits left behind after the previous glacial period, making any recurrence only possible following a new glaciation. After facts and arguments supporting this conclusion were published in 2004, the development of the Ormen Lange gas field was considered unlikely to increase the risk of triggering a new slide.

See also Arctic methane emissions Tsunamis affecting the British Isles Prehistoric submarine landslides

References

Further reading Williams, Sarah C. P. (16 February 2016). "News Feature: Skimming the surface of underwater landslides". Proceedings of the National Academy of Sciences of the United States of America. 113 (7): 1675–78. Bibcode:2016PNAS..113.1675W. doi:10.1073/pnas.1524012113. PMC 4763740. PMID 26884637. Walker, James; Gaffney, Vincent; Fitch, Simon; Muru, Merle; Fraser, Andrew; Bates, Martin; Bates, Richard (2020). "A great wave: the Storegga tsunami and the end of Doggerland?". Antiquity. 94 (378): 1409–1425. doi:10.15184/aqy.2020.49. hdl:10454/18239. ISSN 0003-598X. Woodroffe, Sarah A.; Hill, Jon; Bustamante-Fernandez, Emmanuel; Lloyd, Jerry M.; Luff, Jake; Richards, Sarah; Shennan, Ian (2023). "On the varied impact of the Storegga tsunami in northwest Scotland". Journal of Quaternary Science. 38 (8): 1219–1232. Bibcode:2023JQS....38.1219W. doi:10.1002/jqs.3539. ISSN 0267-8179.

External links BBC: The moment Britain became an island, 14 February 2011

Illustrations

Worked examples

Example 1 — a first encounter with Storegga Slide

Start with the simplest possible case. Write down what Storegga Slide claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In earth science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Storegga Slide before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Storegga Slide ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Storegga Slide

In research: Storegga Slide appears in earth science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Storegga Slide in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Storegga Slide is common in secondary-school and first-year university syllabi. It links to neighbouring topics 7th millennium BC, Geology of Norway, Historical geology, so understanding it makes those chapters shorter.
In everyday life: Look for Storegga Slide outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Storegga Slide in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Storegga Slide means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Storegga Slide out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Storegga Slide in simple terms?

Why does Storegga Slide matter?

Because it connects several earth science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Storegga Slide?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Storegga Slide.