Deep-seated landslides pose a potential threat to coastal settlements, shipping routes, and the natural environment of the polar regions. However, the occurrence, dynamics and impact of such landslides under a warming climate are poorly understood owing to scarce observational data. Here we investigate two deep-seated rockslides on the permafrost coastline of Forkastningsfjellet, Svalbard. Along this coastline, which was dormant for at least the last 80 years, a 175,000 m3 rockslide occurred in August 2016, followed by a second rockslide of 750,000 m3 in November 2022. Based on extensive field data collection starting in 2017, which includes the acquisition and differencing of drone-based DEMs, point-based displacement measurements (dGNSS), ground surface temperature logging, and field mapping, we document accelerating surface deformation and the redirection of the drainage pathways that drive the dynamics of the unstable slope. We show that the 2022 rock slope failure was governed by rapid fluvial incision and accelerated thermokarst development along colluvium-covered, pre-existing zones of weakness, which we interpret as permafrost degradation and enhanced surface run-off resulting from climate warming. We attribute the final triggering of the rockslide to the loss of cohesion and increasing pore water pressures due to thawing ground and cleft ice within the joint system. Looking to the future, we argue for the likely emergence of a positive feedback loop between increasing water availability, due to permafrost thaw and changing precipitation trends, and rock mass deformation.

In many Arctic regions, marine coastlines change rapidly in our currently warming climate. In contrast, coastal rock cliffs on Svalbard are considered to be relatively stable. Long-term trends of coastal-retreat rates for rock cliffs on Svalbard remain unknown, but quantifying them could improve our understanding of coastal dynamics in the Canadian Arctic Archipelago. This study presents coastal-retreat rates for rock cliffs along several kilometres of Br & oslash;ggerhalv & oslash;ya, Svalbard. The analysis relies on high-resolution orthoimages from 1970, 1990, 2010, and 2021. The data are corroborated by high-precision dGNSS (differential Global Navigation Satellite System) measurements obtained along selected segments of the coastline. Our analysis reveals statistically significant acceleration in coastal-retreat rates across Br & oslash;ggerhalv & oslash;ya between 2010 and 2021. The northeast-facing coastline features fairly stable conditions, with retreat rates of 0.04 +/- 0.06 ma-1 (1970-1990; calculated retreat rate +/- the corresponding measurement uncertainty), 0.04 +/- 0.04 ma-1 (1990-2010), and 0.06 +/- 0.08 ma-1 (2010-2021). Along the southwest-facing coastline, higher retreat rates of 0.26 +/- 0.06 ma-1 (1970-1990), 0.24 +/- 0.04 ma-1 (1990-2010), and 0.30 +/- 0.08 ma-1 (2010-2021) were calculated. For the most recent decade, this corresponds to an increase of 50 % for the northeast-facing coastline and an increase of 25 % for the southwest-facing coastline. Furthermore, for the northeast-facing coastline, the proportion of the coastline affected by erosion increased from 47 % (1970-1990) to 65 % (2010-2021), while it stayed consistently above 90 % for the southwest-facing coastline. The recent acceleration in retreat rates coincides with increasing storminess and retreating sea ice, factors that can enhance coastal erosion.

Abstract. In many Arctic regions marine coastlines change rapidly in the currently warming climate. In contrast, coastal rock cliffs on Svalbard are considered to be comparably stable, based on previous studies that considered only a few years and limited coastal reaches. Long-term trends of coastal retreat rates in rock cliffs on Svalbard are unknown so far, but their quantification could improve the understanding of coastal dynamics on the Arctic archipelago. This study presents coastal retreat rates in rock cliffs along several kilometers of the Brøgger peninsula, Svalbard. The work is based on high-resolution orthoimages from 1970, 1990, 2010, and 2021, corroborated by high-precision dGNSS measurements along selected segments of the coastline and by rock surface temperature measurements during the period 2020–2021. Our analysis shows that coastal retreat rates accelerate statistically significant along the Brøgger peninsula in the time period of 2010 to 2021. This is true for both the northeast facing coastline, with retreat rates increasing from 0.04 ± 0.06 m/a (1970–1990) and 0.04 ± 0.04 m/a (1990–2010) to 0.07 ± 0.08 m/a (2010–2021) and the southwest facing coastline, where retreat rates of 0.26 ± 0.06 m/a (1970–1990), 0.24 ± 0.04 m/a (1990–2010) and 0.30 ± 0.08 m/a (2010–2021) are measured. Furthermore, the parts of the coastline affected by erosion increase along the northeast facing coastline from 47 % (1970–1990) to 65 % (2010–2021), while they stay consistently above 90 % along the southwest facing coastline. Measurements of rock surface temperature show mean annual values close to the thaw threshold with −0.49 °C at the southwest facing coastline, while records at the northeast facing coastline are lower with −1.64 °C. The recently accelerated retreat rates coincide with increasing storminess and retreating sea ice, together with increasing ground temperatures, all factors that can enhance coastal erosion.

Rock glaciers are geomorphological expressions of permafrost. Close to sea level in northernmost Norway, in the subarctic Nordkinn peninsula, we have observed several rock glaciers that appear to be active now or were active in the recent past. Active rock glaciers at this elevation have never before been described in Fennoscandia, and they are outside the climatic limits of present-day permafrost according to models. In this study, we have investigated whether or not these rock glaciers are active under the current climate situation. We made detailed geomorphological maps of three rock glacier areas in Nordkinn and investigated the regional ground dynamics using synthetic aperture radar interferometry (InSAR). One of the rock glaciers, namely the Ivarsfjorden rock glacier, was investigated in more detail by combining observations of vertical and horizontal changes from optical images acquired by airborne and terrestrial sensors and terrestrial laser scans (TLSs). The subsurface of the same rock glacier was investigated using a combination of electrical resistivity tomography (ERT) and refraction seismic tomography (RST). We also measured ground surface temperatures between 2016 and 2020, complemented by investigations using an infrared thermal camera, and a multi-decadal climatic analysis. We mapped the rock glaciers in the innermost parts of Store and Lille Skogfjorden as relict, while the more active ones are in the mouths of both fjords, fed by active talus in the upper slopes. Several of the rock glaciers cross over both the Younger Dryas shoreline (25 m a.s.l.) and the Early to Mid-Holocene shoreline at 13 m a.s.l. Both InSAR and optical remote sensing observations reveal low yearly movement rates (centimetres to millimetres per year). The ERT and RST suggest that there is no longer permafrost and ground ice in the rock glacier, while temperature observations on the front slope indicate freezing conditions also in summer. Based on the in situ temperature measurements and the interpolated regional temperature data, we show that the mean annual air temperature (MAAT) of the region has risen by 2 ∘C since the late 19th century to about 1.5 ∘C in the last decade. MAATs below 0 ∘C 100–150 years ago suggest that new rock glacier lobes may have formed at the end of the Little Ice Age (LIA). These combined results indicate that the Nordkinn rock glaciers are transitioning from active to relict stages. The study shows that transitional rock glaciers are still affected by creep, rock falls, snow avalanches, etc., and are not entirely dynamically dead features. Our contrasting results concerning permafrost presence and rock glacier activity show the importance of a multi-methodological approach when investigating slope processes in the edge zones of permafrost influence.

In the context of global warming, ice patches are increasingly important foci of high-elevation archaeology. Langfonne in Jotunheimen, central southern Norway, is uniquely suited to provide a window onto site formation processes and taphonomy in this novel archaeological setting. Here the site record from systematic survey includes the largest number of arrows, bones and antlers from a single ice patch worldwide. Combining data from these finds with the results of glaciological investigations provides an opportunity to interpret the influence of archaeological site formation processes and taphonomy on chronological and spatial patterning. It is inferred that the spatial patterning of artefacts at Langfonne is partly a result of displacement by ice movement, meltwater and other natural processes. Nevertheless, the finds yield information regarding past hunting practices and the extent of ice at different times. An early cluster of finds from c.6000 cal yr BP may result from ice deformation which has brought early objects to the surface. The number of arrows increases from c. 1700 cal yr BP onwards, peaking around c.1200 cal yr BP. Artefacts from this period show a wide spatial distribution indicating both the preferential survival of more recent finds and that they were lost when the ice patch was large. Based on comparison with the chronology of natural bone and antler samples from the site, the greater number of finds of this date may also reflect a period of increased hunting.

Subarctic peatlands underlain by permafrost contain significant amounts of organic carbon. Our ability to quantify the evolution of such permafrost landscapes in numerical models is critical for providing robust predictions of the environmental and climatic changes to come. Yet, the accuracy of large-scale predictions has so far been hampered by small-scale physical processes that create a high spatial variability of thermal surface conditions, affecting the ground thermal regime and thus permafrost degradation patterns. In this regard, a better understanding of the small-scale interplay between microtopography and lateral fluxes of heat, water and snow can be achieved by field monitoring and process-based numerical modeling. Here, we quantify the topographic changes of the Šuoššjávri peat plateau (northern Norway) over a three-year period using drone-based repeat high-resolution photogrammetry. Our results show thermokarst degradation is concentrated on the edges of the plateau, representing 77 % of observed subsidence, while most of the inner plateau surface exhibits no detectable subsidence. Based on detailed investigation of eight zones of the plateau edge, we show that this edge degradation corresponds to an annual volume change of 0.13±0.07 m3 yr−1 per meter of retreating edge (orthogonal to the retreat direction). Using the CryoGrid3 land surface model, we show that these degradation patterns can be reproduced in a modeling framework that implements lateral redistribution of snow, subsurface water and heat, as well as ground subsidence due to melting of excess ice. By performing a sensitivity test for snow depths on the plateau under steady-state climate forcing, we obtain a threshold behavior for the start of edge degradation. Small snow depth variations (from 0 to 30 cm) result in highly different degradation behavior, from stability to fast degradation. For plateau snow depths in the range of field measurements, the simulated annual volume changes are broadly in agreement with the results of the drone survey. As snow depths are clearly correlated with ground surface temperatures, our results indicate that the approach can potentially be used to simulate climate-driven dynamics of edge degradation observed at our study site and other peat plateaus worldwide. Thus, the model approach represents a first step towards simulating climate-driven landscape development through thermokarst in permafrost peatlands.

Satellite radar altimetry is widely used to measure glacier and ice sheet elevation changes, but can suffer from uncertainties related to geolocation and signal penetration. The unique capabilities of ESA's CryoSat-2 allow for accurate geolocation but impacts from signal penetration persist. This study uses surface elevations from Global Navigation Satellite System and airborne laser transects over the Austfonna ice cap, Svalbard, to measure the elevation bias of CryoSat-2 Point-of-closest-approach (POCA) and swath points, and to provide validation for dhdt estimates derived through the application of a least-squares plane-fit algorithm to these data. The mean elevation bias of swath points varies between 1 and 1.5 m of penetration, which is close to observed winter snow depths. Histograms of POCA elevation bias for the applied leading-edge retracker peak near the surface, with a distribution skewed towards the sub-surface. At the onset of surface melt, surface scattering dominates backscatter, and penetration reduces. This results in spurious peaks in derived elevation and mass change time series. In spite of this seasonal variability in elevation bias, the validation dhdt dataset demonstrates that the CryoSat-2 dhdt estimates are robust on multi-year timescales. The transition from volume to surface scattering suggests the potential to estimate yearly snowpack thickness.

Peat plateaus are a major type of permafrost landscape in Arctic and Siberian lowlands. They represent a substantial pool of several hundreds of petagrams of organic carbon that has the potential to contribute to the Permafrost Carbon Feedback. The thermal response of these soils to the climate signal is complex and implies the interaction of various surface and subsurface processes operating at a very small spatial scale involving water, snow and heat fluxes and surface subsidence. As these processes have the ability to generate feedbacks between each other and trigger non-linear evolutions of the landscape, they challenge our abilities to measure and model them. Peat plateaus in Northern Norway have been actively degrading over at least the last 60 years. They thus offer a precious opportunity to measure and model the degradation patterns they exhibit. We present new topographical observations derived from drone-based photogrammetry that we acquired for one site in Northern Norway. Over a period of 3 years, these Digital Elevation Models allows quantifying precisely the surface subsidence and resulting lateral degradation of the peat plateaus. In a second time, we use the land surface model CryoGrid to model the observed patterns. The model is able to (i) simulate the snow fluxes and the water and heat sub-surface fluxes within the plateau and between the plateau and the surrounding wet mire and to (ii) represent the soil surface subsidence due to excess ice melt in the soil. We implement a set up that discretize the interface between the peat plateaus and the wet mire and force the Surface Energy Balance module of the model with climatic data derived from regional atmospheric modelling. Our simulations manage to reproduce the degradation speed we observe in our topographical data. We also present a sensitivity analysis of the degradation speed to snow cover and to the geometry of the peat plateaus and show how the feedbacks between the dynamical topography and the lateral fluxes of snow and water can trigger rapid permafrost thawing and fast degradation of permafrost landscapes.

Abstract. Subarctic peatlands underlain by permafrost contain significant amounts of organic carbon and our ability to quantify the evolution of such permafrost landscapes in numerical models is critical to provide robust predictions of the environmental and climatic changes to come. Yet, the accuracy of large-scale predictions is so far hampered by small-scale physical processes that create a high spatial variability of surface ground thermal regime and thus of permafrost degradation patterns. In this regard, a better understanding of the small-scale interplay between microtopography and lateral fluxes of heat, water and snow can be achieved by field monitoring and process-based numerical modeling. Here, we quantify the topographic changes of the Šuoššjávri peat plateau (Northern Norway) over a three-years period using repeated drone-based high-resolution photogrammetry. Our results show that edge degradation is the main process through which thermal erosion occurs and represents about 80 % of measured subsidence, while most of the inner plateau surface exhibits no detectable subsidence. Based on detailed investigation of eight zones of the plateau edge, we show that this edge degradation corresponds to a volumetric loss of 0.13 ± 0.07 m3 yr−1 m−1 (cubic meter per year and per meter of plateau circumference). Using the CryoGrid land surface model, we show that these degradation patterns can be reproduced in a modeling framework that implements lateral redistribution of snow, subsurface water and heat, as well as ground subsidence due to melting of excess ice. We reproduce prolonged climate-driven edge degradation that is consistent with field observations and present a sensitivity test of the plateau degradation on snow depth over the plateau. Small snow depth variations (from 0 to 30 cm) result in highly different degradation behavior, from stability to fast degradation. These results represent a new step in the modeling of climate-driven landscape development and permafrost degradation in highly heterogeneous landscapes such as peat plateaus. Our approach provides a physically based quantification of permafrost thaw with a new level of realism, notably, regarding feedback mechanisms between the dynamical topography and the lateral fluxes through which a small modification of the snow depth result in dramatic modifications of the permafrost degradation intensity. In this regard, these results also highlight the major control of snow pack characteristics on the ground thermal regime and the potential improvement that accurate snow representation and prediction could bring to projections of permafrost degradation.

Instrumental monitoring of displacement rates of slow-moving rockslides is limited to an insufficient length of the pre-catastrophic failure deformation time. Prehistorical slip rates need to be considered to provide context for monitoring data in relation to the length of the failure process. Cosmogenic Be-10 exposure ages (n = 10) on the backscarp of the Gamanjunni-3 rockslide (northern Norway) are between 5.3 +/- 0.5 ka and 1.2 +/- 0.1 ka. These ages were adjusted for prefailure nuclide production at depth based on the Be-10 concentration in quartz from a stable horizontal bedrock surface above the rockslide. Displacement initiated between 6.6 and 4.3 ka with a relatively fast or instantaneous displacement rate that decelerated a few hundred years after initiation. Slide initiation coincided with the end of the Holocene thermal optimum in northern Norway. The age-height relationship on the backscarp yields an average paleo-slip rate of 28 (-5/+7) mm/yr. This is significantly slower than present-day rates of 54 mm/yr. However, during slide initiation, slip rates were faster than present-day rates. Considering its location within the modern permafrost zone and the observations from instrumental and Holocene displacement rates, we suggest that future global climate changes will influence the Gamanjunni-3 block slip rate.

Field and seismic observations show that numerous sills exhibit lobate morphologies. Each lobe corresponds to a distinct igneous segment exhibiting a finger-like shape, the long axis of which is commonly interpreted as a magma-flow indicator. Robust understanding of the emplacement mechanisms of finger-shaped sills, and direct observations supporting finger orientation as magma-flow indicator are lacking. In this paper, we present the results of detailed structural mapping on an exceptional, easily accessible 1-km long outcrop in the Neuquén Basin, Argentina, that exhibits a sill, its contacts and the structures in the finely layered sedimentary host rock. We show that the sill is made of distinct segments that grew, inflated or coalesced. We also demonstrate that the fingers were emplaced according to the viscoelastic fingering or viscous indenter models, with no field evidence of tensile elastic fracture mechanism as commonly assumed in mechanical models of sill emplacement. We identified new structural criteria at the intrusion's contacts for inferring magma flow direction during the magma emplacement. Our small-scale structural observations carried out on a seismic-scale outcrop have the potential to considerably aid the structural interpretation of seismic data imaging igneous sills, i.e. to fill the standard gap between outcrop-scale field observations and seismic-scale geophysical data.

Despite numerous spectacular archaeological discoveries worldwide related to melting ice patches and the emerging field of glacial archaeology, governing processes related to ice patch development during the Holocene and their sensitivity to climate change are still largely unexplored. Here we present new results from an extensive 6-year (2009–2015) field experiment at the Juvfonne ice patch in Jotunheimen in central southern Norway. Our results show that the ice patch has existed continuously since the late Mesolithic period. Organic-rich layers and carbonaceous aerosols embedded in clear ice show ages spanning from modern at the surface to ca. 7600 cal years BP at the bottom. This is the oldest dating of ice in mainland Norway. The expanding ice patch covered moss mats appearing along the margin of Juvfonne about 2000 years ago. During the study period, the mass balance record showed a strong negative balance, and the annual balance is highly asymmetric over short distances. Snow accumulation is poorly correlated with estimated winter precipitation, and single storm events may contribute significantly to the total winter balance. Snow accumulation is approx. 20 % higher in the frontal area compared to the upper central part of the ice patch. There is sufficient meltwater to bring the permeable snowpack to an isothermal state within a few weeks in early summer. Below the seasonal snowpack, ice temperatures are between −2 and −4 °C. Juvfonne has clear ice stratification of isochronic origin.

Large rockslope deformations are characterized by distinctive geomorphic signatures such as up-facing ridges, grabens, open cracks, etc. which extend along large sections of valley flanks. They often present relatively low displacement rates (up to tens of mm/y). Among the different factors that condition their development, local relief, structural conditions, rock mechanic behavior, and time are the key factors. In Norway, large scale rockslope deformation are widely represented. In this work we give an overview of the conditioning factors of four unstable slopes in the Sogn og Fjordane county, and their current degree of activity by using field mapping, remote sensing and different monitoring techniques such as dGPS and InSAR.

We report on the activities related to the IAG Subcommission 1.3f "Regional Reference Frame for Antarctica". Campaign-style GPS observations have been carried out since 1995. Based on the Bernese GNSS Software the latest analysis yields results for about 30 stations aligned to the terrestrial reference frame solution IGS08. The obtained station motions are discussed in the context of plate kinematics and glacial-isostatic adjustment. It is demonstrated that the activities are a valuable contribution both to the ITRF densification in Antarctica and to geodynamic research.

Gamanjunni 3 is an unstable rock slope in Manndalen valley, northern Norway that shows active deformation. Structural mapping and analyses of terrestrial laser scans identified many discontinuity sets, but none of those may act as a basal failure surface based on kinematical analysis. Hence, decomposed InSAR data from two different satellite geometries was used to understand the failure mechanism of Gamanjunni 3. This 2D InSAR data allows quantification of all displacement components and the dip of the total displacement vector in an east-west plane and is covering almost the entire surface of the unstable rock slope. At the top of Gamanjunni 3, 2D InSAR data show up to 6 cm displacement per year with a dip angle of 50°. This is in agreement with the displacement measured from differential GNSS. The displacement rate as well as the dip angle decrease gradually downwards towards the toe. The displacement vector at the top of Gamanjunni 3 shows clearly that the uppermost part of the unstable rock slope is a wedge failure along the two rectangular back-scarps. However, the intersection line of these two failure planes does not daylight in the slope. Displacement needs to be transferred to a shallower structure at the lower parts of the unstable rock slope, as for example the sub-horizontal foliation. This is reflected in an approximately horizontal displacement at the toe of Gamanjunni 3. We thus propose a compound biplanar rock slope deformation based on the observed displacement pattern, morphology and structures.

The origin of linear features in mountain terrain that form distinct vertical steps is generally not obvious and has been discussed to be related to either tectonic faulting or gravitational slope deformation. A strong geomorphological lineament running oblique to the slope and forming a convex step in the topography is located on the mountain Middagstinden just west of the valley Innfjorddalen, western Norway. In previous studies this lineament has been interpreted to be the surface expression of a Holocene reverse fault previously called the Berill Fault, indicating the first evidence for neotectonic faulting in southern Norway. Now, detailed structural field mapping has revealed the existence of a set of normal fault planes striking subparallel to this lineament and to the main extensional faults associated with the Caledonian collapse. Electric resistivity tomography (ERT) profiles of the valley floor and excavated parallel trenches confirm the regional extent of the fault, but the sediments observed in the trenches do not indicate any Holocene activity. Furthermore, the lineament is a limiting structure of a large rock-slope instability. Kinematic feasibility tests based on structural field measurements indicate wedge failure along the intersection of the fault and the local foliation. However, this intersection line is not exposed on the slope surface. Hence, simple wedge or translational sliding along the slope is not feasible, except in its uppermost part. Both the displacements observed by differential global navigation satellite system (dGNSS) surveys and the geomorphological characteristics, for instance, counterscarps, superficial mass movements, coherent slide blocks and slope bulging, indicate complex deformation mechanisms. The deformation evidently changed along the slope in type and degree including planar sliding in the uppermost part, potentially large wedge sliding in the middle part, and incremental internal deformation in a direction out of the slope in the lower part. The complex kinematics and geomorphological characteristics account for the definition of a deep-seated gravitational slope deformation (DSGSD). Furthermore, the findings reveal that the geomorphological lineament is of gravitational origin and not neotectonic. It has formed by a reactivation of the pre-existing, Caledonian, normal fault system due to the DSGSD, and is hence an example of pseudotectonics ('apparent reverse fault').

A newly developed hazard classification system for large unstable rock slopes depends on the evaluation of a number of criteria. These criteria include both displacement rates and the structural development of the unstable slope. Satellite and ground-based interferometric radars have the potential to measure the displacement of active rockslides. By using several complimentary InSAR datasets, with different viewing geometries, we are able to assess both movement criteria and a number of criteria related to structural development of the bounding surfaces.

Nathorstbreen glacier system (NGS) recently experienced the largest surge in Svalbard since 1936, and this was examined using spatial and temporal observations from DEM differencing, time series of surface velocities from satellite synthetic aperture radar (SAR) and other sources. The upper basins with maximum accumulation during quiescence corresponded to regions of initial lowering. Initial speed-up exceeded quiescent velocities by a factor of several tens. This suggests that polythermal glacier surges are initiated in the temperate area before mass is displaced downglacier. Subsequent downglacier mass displacement coincided with areas where glacier velocity increased by a factor of 100–200 times (stage 2). After more than 5 years, the joint NGS terminus advanced abruptly into the fjord during winter, increasing velocities even more. The advance was followed by up-glacier propagation of crevasses, indicating the middle and subsequently the upper part of the glaciers reacting to the mass displacement. NGS advanced ~15 km, while another ~3 km length was lost due to calving. Surface lowering of ~50 m was observed in some up-glacier areas, and in 5 years the total glacier area increased by 20%. Maximum measured flow rates were at least 25 m d−1, 2500 times quiescent velocity, while average velocities were about 10 m d−1. The surges of Zawadzkibreen cycle with ca. 70-year periods.

Catastrophic rock avalanches contribute to rapid landscape evolution and can harm humans directly or by secondary effects such as displacement waves. Predicting the volume, timing, and consequences of rock slope failures is therefore essential to managing risk and interpreting landscape response to climatic or tectonic forcing. Here, we synthesize geologic and geodetic observations to document the spatial pattern of movement rates and failure mechanisms at a landslide complex in western Norway, recently identified with systematic interferometric synthetic aperture radar (InSAR) reconnaissance. A differential global navigation satellite system (dGNSS) and global positioning system (dGPS) campaign confirms active slope deformation with horizontal displacement rates of 1.2 to 2.6  mm  year−1 at four points distributed across the landslide’s ~1.8-km width. Displacement vectors are consistent with landslide movement occurring on pre-existing discontinuity sets, and a broad synform controls failure mechanisms within the landslide complex. Two ~1.5 million m3 blocks are wedge failures, while flexural toppling and planar sliding of smaller blocks occur throughout the landslide complex. Modern movement rates are comparable to or slower than Holocene-averaged displacement rates, suggesting continued steady deformation or stabilization of parts of the landslide with time. However, a large volume failure with typical run-out for rock avalanches would likely reach the subjacent fjord, causing a displacement wave. We suggest that our collaborative approach of integrating a wide variety of geologic and geodetic methods will be useful for more thoroughly documenting additional landslide sites and for making informed decisions about risk management.