Update on Storegga

20 Jul 2020

Clarification on the recent piece from the Daily Mail. The actual study does not mention climate change at all and has been inserted by the Daily Mail journalist, or an editor. It may of course have been inserted by whoever released the press story to the media. The full paper can be read at www.mdpi.com/2076-3263/10/7/270/htm ... The event has nothing to do with climate change and is purely a geological phenomenon. The actual Storegga Slide took place on the continental shelf system off the coast of central Norway and not off the southern Norwegian coast, as I had imagined for a number of years. The effects of the slide were felt mostly in places directly west of the slide, such as the Faero Islands and the Shetlands, even in Greenland. Northern Scotland also bore a brunt of the tsunami and to a lesser extent NE England. It is thought to have been defected from the east coast and travelled like a bore down the North Sea basin. However, this is the first study that has found actual evidence of the tsunami wave, or waves, in the southern North Sea region, off the coast of Lincolnshire. It came about for one reason only. Gaffney, the lead author, is leading a marine archaeology investigation of the North Sea basin, and in the process of doing this came across evidence that suggested, strongly, that a tsunami wave, or waves, struck the region. However, Gaffney et al are at pains to point out that the tsunami wave struck prior to the submergence of Doggerland. That completely alters the picture that earlier studies have made. In the earlier studies the tsunami and the submergence were part and parcel of the same event. In the new study this is not so.

See also https://tallbloke.wordpress.com/2020/07/18/the-tsunami-that-devastated-a... ... Evidence for the Storegga Slide impacting the southern North Sea basin has been lacking until the current marine archaeology investigation that led to this new study. The evidence is said to be multi proxy.

For further information on the Storegga Slide we need to go back a few years and see for example www.ig.uit.no/geo3128/02-Bryn_etal_MPG_2005.pdf ... where we learn that sea level curves show that uplift of Scandinavia (bounce back after the last glaciation) coincided with rapid sea level rise until around 8000 years ago, when it became linear. In other words, sea levels settled down. It goes on to suggest earthquakes off the coast of Norway could feasibly have set in motion the Storegga Slide. Sediments, mostly glacial in origin, are situated off the coast of Norway, north to south, on top of marine clay geology. The Slide occurred when one section of these sediments decided to move downwards from the continental shelf system, into the deeper ocean. We may ask what other factors might be involved in setting in motion a shift of sediments, on a sloping shelf system, sliding down in a rush rather like a cliff fall (taking a huge bite out of a coastal cliff system). This also very often involves sediments laid down on top of a clay layer - or an equally lubricant geological formation. An earthquake seems like a good idea but there are some interesting parallels that also occurred at 8000 years ago. For example, most of the water from the Great Lakes moved into the ocean via the St Lawrence river. At 8000 years ago the Niagara Falls came to prominence as a much greater volume of water egan to move south instead of eastwards. Water always follows the lie of the land which suggests the route southwards may not have been entirely down hill prior to 8000 years ago. Or the route eastwards changed for some reason, and water  would not follow the previous lie of the land. A simlar situation prevailed in the Mediterranean region. The Bosporus was opened up and water from the Mediterranean began, again, to enter the Black Sea, and vice versa, water from the latter also moved to the former. What caused the breach at the Bosporus? There are many such oddities around the world associated with 8000 years ago and that may include a rearrangement of the earth's geoid. A shift in the inclination of tilt of the earth may be to blame. If that is possible. It need not be a great amount. Enough to make water change direction - as at Niagara and the Bosporus. And enough to nudge a bunch of glacial sediments on the continental shelf off Norway to slide into the deeper ocean. Think outside the box and other possibilities spring to mind. Tenuous perhaps but it would explain the shift in sea levels around this point in time as ocean basins realigned themselves with the new geoid (leading to the submergence of continental shelf systems around Britain and Ireland, even as far south as the Solent, as well as the drowning of Sunda Land in SE Asia). Presumably, there would have been emergence somewhere in other parts of the world. One to look out for.