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The North Atlantic Oscillation is the dominant atmospheric driver of North Atlantic climate variability with phases corresponding to droughts and cold spells in Europe. Here, we exploit a suggested anti-correlation of North Atlantic Oscillation-phase and north-eastern North Atlantic primary productivity by investigation of south-eastern Norwegian Sea sediment cores spanning the last 8000 years. Age model uncertainties between 2 and 13 years for the period 1992–1850 AD allows for the proxy to observational data calibration. Our data suggest that Ca/Fe core-scanning results reflect sedimentary CaCO3 variability in the region. Cross-correlating the Ca/Fe record with nearby phytoplankton counts and dissolved O2 data suggests that Ca/Fe can be used as a proxy for primary productivity variability in the region. Our data support an anti-correlation of primary productivity to the winter North Atlantic Oscillation index. Hence, we propose a sub-decadally resolved palaeo-North Atlantic Oscillation reconstruction based on an open-ocean record spanning the last 8000 years.

For the Last Glacial Maximum (LGM), there is a general consensus that the Fennoscandian Ice Sheet coalesced with the British–Irish Ice Sheet in the Central North Sea forming the southwestern part of the Eurasian Ice Sheet. It is also generally accepted that the ice margin at LGM was situated close to the shelf edge from the Kara Sea to the Irish margin and that the southern margin in the North Sea was located along the northeast–southwest-trending Dogger Bank in the Southern North Sea. In this review, we will first present some of the landforms and evidence representing the Weichselian/Devensian (Last Glacial Cycle) maximum position of the Eurasian Ice Sheet in the North Sea and along the Mid-Norwegian continental margin and then present some of the subglacial form elements that may partly be attributed to the LGM in these regions.

Submarine landslides are common at glaciated continental margins. The onset of large-scale landslides coincides with the initiation of Northern Hemisphere glaciations in the Quaternary. This implies that processes related to glacial cycling provide favourable conditions for submarine landslides at high-latitude margins. Potential processes include glacial deposition patterns and enhanced seismicity. It is also possible that advances and retreats of ice sheets, a highly dynamic process in geologic terms, makes slopes discernible to failure by modifying the stress regime. Here, we quantify this effect using 2D Finite Element modelling of a glaciated continental margin. Different model runs investigate the pore pressure development in homogeneous as well as layered slopes during glaciation when loaded by an ice stream with one or multiple ice advances. Ice streams cause significant variations in excess pore pressure in the very shallow sediment sequences at the continental shelf. However, lateral fluid flow is not efficient enough to increase pore pressures significantly at the slope, where large-scale submarine slides are observed. Hence, while ice sheet dynamics appear to favour the occurrence of shallow slides close to the shelf edge, ice sheets seem to be irrelevant for the generation of large-scale submarine landslides at the continental slope.

Sediments deposited during glacial-interglacial cycles through the Early to Mid-Pleistocene in the North Sea are chronologically poorly constrained. To contribute to the chronology of these units, amino acid racemization (AAR) and strontium (Sr) isotope analyses have been performed on samples from four shallow borings and one oil well along a transect in the northern North Sea. D/L Asp (aspartic acid) values obtained through reverse-phase liquid chromatography in the benthic foraminiferal species Elphidium excavatum is focused on because of consistent results and a good stratigraphic distribution of this benthic species. For the Early Pleistocene, an age model for the well 16/1–8, from the central part of the northern North Sea based on Sr ages allows for dating of the prograding wedges filling the pre-Quaternary central basin. A regional calibration curve for the racemization of Asp in Elphidium excavatum is developed using published ages of radiocarbon-dated samples and samples associated with the previously identified Bruhnes/Matuyama (B/M) paleomagnetic boundary and a Sr age from this study. Based on all the available geochronological evidence, samples were assigned to marine oxygen isotope stages (MIS) with uncertainties on the order of 10–70 ka. Sr ages suggest a hiatus of

Here we present the first compilation of sediment volumes, sedimentation rates, and chronology of Quaternary sediment packages along the entire marine margin of the Eurasian ice sheets (EurIS; British–Irish, Kara–Barents Sea–Svalbard, and Fennoscandian). This compilation allows for a subdivision of the EurIS development into three phases (2.6–1.5 Ma, 1.5–0.78 Ma, and 0.78–0 Ma). At the start of the Quaternary, sedimentation rates increased, relative to pre-Quaternary rates, by an order of magnitude. This abruptness in rate change excludes tectonic raising of landmasses as the main factor, but more likely reflects climate change through increased glacial erosion. The sediment distribution data suggest that the Kara–Barents Sea–Svalbard Ice Sheet (KBSIS) already was quite large at the beginning of the Quaternary, and well before 1.5 Ma it extended to the shelf edge and coalesced with the Fennoscandian Ice Sheet (FIS), which prior to 1.5 Ma most likely was located near the coast. Large ice streams and intense glacial erosion characterized the KBSIS in the 1.5–0.78 Ma time period, whereas the FIS at that time extended farther out on the continental shelf. After 0.78 Ma, a north-south change in EurIS development occurred. In the FIS and the British–Irish Ice Sheet (BIIS), large ice streams developed and shelf-edge glaciations occurred nearly 1 m.y. later compared to the KBSIS. The FIS and BIIS also repetitively coalesced in the North Sea. A significant drop in sediment input along the KBSIS marine margin, to the lowest Quaternary level, suggests a less erosive KBSIS.

In this study, identified mass transport deposits (MTDs) in previously analyzed as well as new sediment cores and seismic profiles from 22 fjord systems and six lakes in west and mid-Norway are compiled in order to close knowledge gaps in the understanding of how mass movements relate to seismic activity and climatic changes affecting the sedimentary systems. A total of 125 postglacial MTDs have been identified and dated in the studied systems. Mass movement frequency plots suggest high mass movement activity for two periods in the Early Holocene (11,000–9700 and 8300–7700 cal. yrs BP), a quiescent period in the mid-Holocene, and a mass movement reactivation at ~4200 cal. yrs BP. The evaluation of trigger mechanisms makes us infer that some of the mass movements identified are most likely related to climatic processes and tsunamis. However, most of the events seem to be caused by regional seismic activity, resulting in failure of climatically-preconditioned slopes. We suggest that at least 36 individual regional earthquakes (M > 6) have occurred in west and mid-Norway through the Holocene. Earthquake recurrence rates of 1/80 years are estimated for the period directly after the last deglaciation (~12,800–11,600 cal. yrs BP), 1/200 years for the Early Holocene and 1/200 years for the last 4000 years of the Holocene time period. Comparisons with studies from other previously glaciated settings indicate that both Scandinavia and the Alps show similar trends as west and mid-Norway, but not Eastern Canada. This most likely reflects a later deglaciation of the Laurentide Ice Sheet.

Highlights • Increased glacial sedimentation rates do not generate sufficient overpressure to trigger a landslide. • Simulated overpressures for different sedimentation scenarios do not significantly differ. • A glacimarine layer underneath rapidly-deposited sediments is important for overpressure build-up. • An earthquake of M6.9 or larger at a short distance from the Tampen Slide headwall could have triggered the Tampen Slide. Abstract Trough mouth fans are environments characterized by high sediment supply during glacial stages and the occurrence of large-scale instabilities. The geological record indicates that several of these environments have failed repeatedly resulting in large submarine landslides. The roles of sedimentation rate, weak layers, glacial loading and unloading as well as seismic activity on triggering megaslides in trough-mouth-fan systems is still unclear. A better understanding of the preconditioning factors, triggers and consequences of these landslides is crucial due to the hazard they pose to coastal communities and offshore industries. In this paper, we focus on the North Sea Trough Mouth Fan, which is the result of massive glacial sediment input delivered to the shelf edge through the Norwegian Channel, southeast Nordic Seas margin. The Tampen Slide, one of several large paleo-landslides that have happened within the North Sea Trough Mouth Fan, took place at c. 130 ka (end of MIS 6), and removed an estimated 1800 km3 of sediment. Here, we use boundary conditions from the Tampen Slide and 2D Finite Element Modeling (Abaqus software from Simulia) to evaluate the effects of variations in sedimentation rates as well as sediment properties on the generation of excess pore pressure, fluid flow, and slope stability along the axis of the trough-mouth-fan system. The model domain, 40 km in length and 2 km in height, is dominated by glacigenic debris flows and glacimarine sediment deposits. We use geotechnical data measured on samples of glacigenic and glacimarine sediment deposits from the nearby Ormen Lange gas field area to constrain the model. We evaluate the stability of the slope under various scenarios, including constant sediment loading, episodic changes in sedimentation rates and abrupt pulses in sediment delivery for a 61 kyr period (MIS 6). The models show that increased sedimentation rates during glacial stages do not generate sufficient excess pore pressure to set off a landslide. Furthermore, the simulated overpressures for the different sedimentation scenarios do not significantly differ at the end of the model runs. The results also highlight the importance of a basal glacimarine sediment layer underneath the rapidly-deposited sediments for the build-up of overpressure. Consequently, this glacimarine sediment layer has the inherited potential to act as a weak layer facilitating instability. However, as overpressure due to sediment deposition alone does not result in slope failure, we couple the preconditioned slope with earthquake ground shaking. Based on attenuation models, an earthquake of approximately M6.9 or larger at a short distance from the Tampen Slide headwall could have triggered the landslide. Therefore, we suggest glacial sedimentation and a glacimarine sediment layer to represent preconditioning factors, and seismic shaking as the final trigger mechanism for the Tampen Slide, i.e. similar to the situation that lead to the development of the Storegga Slide in the same area.

The timing, rates and patterns of retreat of western sectors of the last Eurasian Ice Sheet (EurIS) are poorly constrained, hampered by limited observations from the marine domain. A better knowledge of the deglaciation of the NW European marine areas/continental margins is essential for efforts to understand the role of different controlling factors (such as ice streams, atmospheric and oceanic conditions, relative sea level, morphology and substrate) on the stability of the EurIS, and also for ice-sheet stability in general. Based on new and existing mapping of glacial landforms, together with a compilation of existing and recalibrated dates from the NW European shelf, a new reconstruction of the retreating EurIS between 20 and 14 ka BP will be presented. Our reconstruction suggests an initial modest withdrawal from maximum extent to c. 19 ka BP along the entire western marine-terminating margin. From 19ka the two major marine-terminating ice streams, in the Norwegian Channel and Bear Island Trough, begin to retreat/collapse. This destabilisation leads to rapid interior downdraw and the eventual unzipping of the British-Irish and Fennoscandian ice sheets at c. 18.5 ka BP, and the Barents-Kara and Fennoscandian ice sheets between 16 and 15 ka BP. Based on our new reconstruction and modelling results, the importance of factors controlling the nonsynchronous and rapid deglaciation of marine-based sectors and the implications for the stability of the ice sheet, will be discussed. The chronology and patterns of past marine deglaciations provide contextual insight into ice sheet instabilities and the mechanisms behind, underpinning the ongoing retreat of the Greenland and Antarctic ice sheets today.

The aminostratigraphy of up to 1000 m of glacial and interglacial sediments in the North Sea Basin (NSB) is compiled from multiple boreholes sites and dated using strontium isotope (Sr) analysis to provide a chronological framework extending throughout the Quaternary. The Quaternary aminostratigraphy within the NSB can be divided into five amino zones (AZ), AZ1 (youngest) to AZ5 based on alle/Ile ratios which are used to correlate depositional events recorded in sedimentary facies from multiple borehole sites. The new relative and absolute chronology also ties to seismostratigraphy and multi-generational tunnel valley fill. Early Pleistocene sediments produce AZ5 ratios with Sr ages around 1.4–1.5 Ma deposited in marine to glacimarine conditions. Sediments with AZ4 ratios are constrained by Sr ages and magnetic polarity to 1.3–0.9 Ma, spanning the eccentricity to axial tilt insolation periodicity change of the Mid Pleistocene Transition (MPT). Some coarse-grained sedimentary units with AZ4 ratios may be linked to ice proximal deposition during the MPT. Sediments with AZ3 ratios are poorly chronologically constrained to between 1.1 and 0.26 Ma. At least one episode of diminished coarse clasts and increased foraminiferal diversity during this Mid Pleistocene time suggests a progression from ice proximal to warmer, possibly interglacial conditions. Furthermore, the stratigraphically deepest generation of tunnel valleys cut strata with AZ3 ratios indicating subglacial conditions at least once during the Mid Pleistocene. Sediments with AZ2 ratios corresponding to MIS7-5 are tied to seismic units including a thick (up to 40 m) deformation till, suggesting glacial incursion into the NSB during MIS6 followed by tunnel valley cutting of the this till, thought to be an MIS6 event also. The geometry and cross-cutting complexities of such tunnel valleys precludes further correlation of this ice extent. The youngest aminostratigraphic zone, AZ1, is recognised in all boreholes and well constrained to MIS4-2 and the youngest set of tunnel valleys, attributed to a single or multiple glacial advances at this time.

Based on high-resolution TOPAS acoustic data, bathymetric data sets and sediment cores from the Norwegian Channel, the last retreat of the Norwegian Channel Ice Stream has been investigated. Mapping of ice-marginal features such as grounding-zone wedges and terminal moraines off western Norway suggest that the retreat of the grounding line in this part of the channel was interrupted by frequent stillstands, whereas the channel south of the threshold at Jaeren does not have crossing ice-marginal landforms. Three main seismic units have been identified, and, based on their seismic characteristics, in addition to study of sediment cores, these units are interpreted as till (U1), glacial marine sediment (U2) and Holocene hemipelagic sediment (U3). Based on new and published radiocarbon dates of the lower part of U2, combined with dates from the adjacent areas, it is concluded that the grounding line started to retreat from the shelf edge at about 19 ka and that the inner part of Skagerrak was ice free at 17.6 ka. This gives an average retreat rate of 450 m a−1, which is generally higher than mean retreat rates estimated for other palaeo-ice streams (15–310 m a−1).

High resolution acoustic data and a 15.7 m long sediment core from the Hardangerfjorden system, western Norway, have been analyzed to increase our knowledge on depositional environments, submarine mass movement trigger mechanisms and submarine mass movement frequencies in high latitude fjord systems. The seismic profiles analyzed show that an up to 160 m thick glacimarine-dominated unit, of probably Younger Dryas age, has been deposited above the acoustic basement. A < 55 m thick unit, comprising stacked mass transport deposits (MTDs) has been deposited atop the glacimarine unit. The identified mass movement events comprise 19 MTDs (MTD1–19), which have transported sediment volumes of up to 0.4 km3 and initiated turbidity currents resulting in the deposition of up to 13 m thick turbidite layers. The established chronostratigraphical framework reveals high mass movement activity in Hardangerfjorden at 11100–8200 cal. yrs BP (Early Holocene) and at 4100 cal. yrs BP to present (Late Holocene). 14 MTDs have been dated to the Early Holocene, which is a time period characterized by high sedimentation rates (1.1 mm/yr), giving a mass movement recurrence rate of 1/200 years. Several of these failure events are suggested to have been triggered by regional mechanisms such as earthquakes linked to glacioisostatic uplift. Some of the MTDs of that time could potentially be caused by rock avalanches. Furthermore, it seems that the identified 8200 cal. yrs BP MTD5 coincides with the age of the Storegga tsunami, suggesting that processes related to this event may have caused sediment failure in the inner Hardangerfjorden. During the mid-Holocene (8200–4100 cal. yrs BP), a time period which was characterized by low sedimentation rates of 0.1–0.2 mm/yr and a warmer and wetter climate, mass movement events were absent in the study area. The renewed slide activity in the Late Holocene, comprising four MTDs, is probably related to climatic processes, earthquakes and rock avalanches, resulting in a mass movement recurrence rate of 1/1000 years for this time period. This study, thus, underlines the importance of high-latitude fjords, also in a global context, as systems where local, regional and external geological forces interact to impose highly dynamic postglacial depositional environments. publishedVersion

This study describes the distribution and stratigraphic range of the Upper Palaeozoic–Mesozoic succession in the NE Atlantic region, and is correlated between conjugate margins and along the axis of the NE Atlantic rift system. The stratigraphic framework has yielded important new constraints on the timing and nature of sedimentary basin development in the NE Atlantic, with implications for rifting and the break-up of the Pangaean supercontinent. From a regional perspective, the Permian–Triassic succession records a northwards transition from an arid interior to a passively subsiding, mixed carbonate–siliciclastic shelf margin. A Late Permian–earliest Triassic rift pulse has regional expression in the stratigraphic record. A fragmentary paralic to shallow-marine Lower Jurassic succession reflects Early Jurassic thermal subsidence and mild extensional tectonism; this was interrupted by widespread Mid-Jurassic uplift and erosion, and followed by an intense phase of Late Jurassic rifting in some (but not all) parts of the NE Atlantic region. The Cretaceous succession is dominated by thick basinal-marine deposits, which accumulated within and along a broad zone of extension and subsidence between Rockall and NE Greenland. There is no evidence for a substantive and continuous rift system along the proto-NE Atlantic until the Late Cretaceous. publishedVersion

Recent reconstructions suggest that the British-Irish and Fennoscandian ice sheets coalesced and covered the central and northern North Sea from ca. 26 cal. ka BP and until ca. 19 cal. ka BP. At ca. 19 cal. ka BP the Norwegian Channel Ice Stream started to retreat and the ice sheets broke apart at ca. 18.7 cal. ka BP. This led to a drainage of an ice-dammed lake in the southern North Sea northwards via the Norwegian Channel into the SE Nordic Seas. In this paper we combine information from high resolution TOPAS profiles, bathymetric records and shallow borings to study the ice-dammed lake outburst, a common deglaciation process but which rarely has been evidenced in such a detail from the marine realm. A 12 m deep and 3 km wide incision at the northeastern part of the Dogger Bank is suggested to represent the point where the ice-dammed lake breached. The glacial lake outburst flood, which had an estimated peak discharge of 9.8 × 104–2.9 × 105 m3/s and lasted for about 5–15 months, flowed between the withdrawing British-Irish and Fennoscandian ice sheets following the crest of the Ling Bank northwards. Along this path, about 300 km downstream of the break-through point, an up to 10 m thick sediment package with a prograding-aggrading sedimentation pattern, typical for ice-dammed lake outburst deposits, has been deposited. This sediment package was deposited in a high-energy environment, immediately following extensive erosion of the underlying till unit of Last Glacial Maximum age. An oxygen isotope anomaly and an associated ultra-rapidly deposited meltwater plume on the Norwegian continental margin, dated to ca. 18.7 cal. ka BP, also witness this lake outburst. The ice-dammed lake outburst flood occurred when evidence suggest a sea level at least 110 m lower than at present in the region. As the sea level rose, following the melting of the Last Glacial Maximum ice sheet, the Ling Bank Delta developed on top the outburst deposits. The delta, indicating a sea level close to 80 m below present, has an extent of 80 km and up to 12 m deep fluvial channels are associated with the topset beds. This fluvial environment may have lasted until the end of the Younger Dryas time period when the Ling Bank was submerged and attained its present water depth.

Sediment cores from the south-eastern Nordic Seas simultaneously archive the variability of the Fennoscandian Ice Sheet (FIS), the British-Irish Ice Sheet (BIIS) and the regional oceanic conditions. This study aims to contribute to our understanding of the marine-based section of the FIS and the BIIS between 35,000 and 15,000 years BP, by using cores MD99-2283, MD99-2284 and MD99-2289, retrieved along the upper continental slope between the Faroe-Shetland Channel and the Wiring Plateau. For this, we present a revised, radiocarbon based, Bayesian modelled chronological framework and a compilation of new and published sedimentological, geochemical and micro-paleontological datasets. Our results show a possibly first Weichselian FIS/BIIS confluence at ca. 25,500 years BP in the central North Sea, which buttressed the BIIS to the East, potentially leading to a northwards BIIS deflection via the Shetlands. The Norwegian Channel Ice Stream (NCIS) most likely only reached the shelf edge after 23,300 +/- 500 years BP, possibly for the first time during the Weichselian. The NCIS onset directly preceded a pronounced influx of warm Atlantic water to the northern North Sea margin possibly implying forcing through ocean melt. We find a highly variable NCIS, with three similar to 1400 yearlong episodes of increased ice rafted debris flux interrupted by similar to 600 yearlong minima. When compared to other sides of the European Ice Sheet, these episodes appear to correlate well, suggesting a common forcing mechanism. In conclusion, our data supports recent suggestions that the last glacial stage of the BIIS was more extensive in the central North Sea and the confluence later than previously thought.

Content and fluxes of ice transported sand-sized and gravel-sized, lithic particles in marine sediment cores are a common tool used to reconstruct glacial variability. Ice-rafted debris datasets are currently acquired in several different and often time consuming ways, and within various grain size fractions. This paper proposes a novel workflow using an automated method to count ice-rafted debris to reduce analysis time and subjectivity. The described method is based on the instrument ‘Morphologi G3’ from Malvern Instruments Limited, and includes all pre-processing and post-processing steps. This particle characterization tool is an automated microscope combined with a proprietary software package. In the present study, the analysis was performed on the 150 to 1000 μm fraction. If desired, grain counts can be carried out on the entire sand and silt fractions, but then at the expense of considerably greater turnover time. A total of 350 sediment samples from core MD99-2283, taken on the upper continental slope at the southern part of the north-east Atlantic margin, were counted with this automated method. In addition, a total of 161 samples were counted manually as a control on the reliability of the scanning. The comparison of automated versus manually counted biogenic and lithic material shows a convincing correlation between both methods. The turnover time per automatically counted sample is around 20 minutes, the method requiring less experience and skills than manual counting. The results yield a promising, time saving new technique to achieve high-resolution ice-rafted debris counting records with acceptable error margins. This article is protected by copyright. All rights reserved.

Highlights • The basement at the mid-Norwegian More Margin is dominantly felsic in composition. • A lower crustal body is interpreted as a mixture of continental blocks and eclogite. • The thickness of the outer lower crustal body is twice as thick on the East Greenland Margin. • The thinning during this first phase of post-Caledonian extension was highest for proto Norway. Abstract The inner part of the volcanic, passive More Margin, mid-Norway, expresses an unusual abrupt thinning from high onshore topography with a thick crust to an offshore basin with thin crystalline crust. Previous P-wave modeling of wide-angle seismic data revealed the presence of a high-velocity (7.7–8.0 km/s) body in the lower crust in this transitional region. These velocities are too high to be readily interpreted as Early Cenozoic intrusions, a model often invoked to explain lower crustal high-velocity bodies in the region. We present a Vp/Vs model, derived from the modeling of wide-angle seismic data, acquired by use of Ocean Bottom Seismograph horizontal components. The modeling suggests dominantly felsic composition of the crust. An average Vp/Vs value for the lower crustal body is modeled at 1.77, which is compatible with a mixture of continental blocks and Caledonian eclogites. The results are compiled with earlier results into a transect extending from onshore Norway to onshore Greenland. Back-stripping of the transect to Early Cenozoic indicates asymmetric conjugate magmatism related to the continental break-up. Further back-stripping to the time when most of the Caledonian mountain range had collapsed indicates that the thinning during the first phase of extension was about 25% higher for proto Norway than proto Greenland.

Mass movements are a frequent sedimentary process in the marine realm, affecting both glaciated and non-glaciated continental margins. Here a 3D seismic data set from the North Sea Fan, NE Atlantic margin, is used to study internal architecture, external geometry and surface geomorphology of different types of buried sediment transport. We identify three mass transport deposits, at a depth of ca 100–1000 m below seabed, corresponding to the previously mapped Tampen (~130 ka) and M½re (~300 ka) slides and the Stad (~400 ka) Slide, identified in this study. These slides all eroded underlying sedimentary units and their surfaces include curvilinear ridges up to 20 m high and 10–15 km long. Locally, the slide surfaces also include rafted slide blocks, up to 200 m wide, 300 m long and 30 m high. We relate the curvilinear ridges and the slide blocks to submarine spreading. Intervals of glacigenic debris flows are identified between the mass transport deposits. These lens-shaped bodies are seen in plan to be flows that widen downslope and which are fed from 10 to 20 m deep, 50–200 m wide and >2 km long transport channels that extend from the paleo-shelf edge. Analyses of time slices suggest that such flows may have been operating on the North Sea Fan for the last ~1.1 million years.

Based on high-resolution bathymetric records, sub-bottom profiles and sediment cores, we study postglacial mass transport deposits, slide scar complexes, cyclic steps and rockfall deposits as indicators of mass failures in the inner Hardangerfjorden system, western Norway. The stacked mass transport deposits show thicknesses of up to 4 m and witness that the inner Hardangerfjorden has been a site of repetitive mass failure events, potentially triggered by earthquakes related to glacioisostatic uplift. The cyclic steps, affecting an area of about 2 km2 in the innermost fjord, have wave lengths of 40 m, heights of 5 m and are most likely related to fluvial sediment supply. Seven slide scar complexes, with stratigraphy-cutting scar heights of 6–34 m, are identified on the basin plain of the fjord. These are all associated with large depocenters along the fjord flanks, suggesting a link between locations of high sediment supply and mass failure. Although rapid deposition might, by itself, induce failures, an external trigger mechanism, such as an earthquake, should also be considered.