Styles of slope instability on a Quaternary sub-arctic continental margin: The northwest flank of the Storegga Slide

Jing, Song, Alves, Tiago ORCID: https://orcid.org/0000-0002-2765-3760 and Omosanya, Kamal'deen O. 2022. Styles of slope instability on a Quaternary sub-arctic continental margin: The northwest flank of the Storegga Slide. Marine Geology 454 , 106933. 10.1016/j.margeo.2022.106933

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Abstract

Submarine landslides are widely recognised around the Northeast Atlantic margin, some of which forming vast slide complexes. On the mid-Norwegian margin, the Storegga Slide complex has been active since the early Pleistocene, first as a regional event (Slide W) at 1.7 Ma, and later culminating in the Storegga Slide sensu stricto at 8.2 ka. By interpreting high-quality seismic data, this work investigates slope instability styles, and their geneses, on the northwest flank of the Storegga Slide complex. Seismic and borehole data prove: i) the presence of two new landslides formed prior to Slide W, ii) that mass-transport complexes occurred during the evacuation of sediment oozes, iii) the existence of a series of cracks on the seafloor, denoting modern slope instability. Fluid accumulation in glacial-marine deposits was a primary factor promoting early instability; fluid pipes increase in number below the oldest landslide deposits, with most pipes terminating at their glide planes. Furthermore, mathematical models show that vertically stacked intervals with weak layers, and older landslide deposits, are able to promote further instability. This work thus suggests episodic fluid flow as the primary factor promoting long-term instability near the Storegga Slide complex. As a corollary, we reveal the stability of the continental slope to still be precarious, at present, on the northwest flank of the Storegga Slide.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Earth and Environmental Sciences
Publisher:	Elsevier
ISSN:	0025-3227
Date of First Compliant Deposit:	17 November 2022
Date of Acceptance:	25 October 2022
Last Modified:	10 Jun 2023 22:22
URI:	https://orca.cardiff.ac.uk/id/eprint/154267

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