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The Himalayan State of Sikkim is prone to some of the world's largest landslides which have caused catastrophic damages to lives, properties and infrastructures in the region. The state capital, Gangtok, has experienced rapid population growth over the last decades. The rate of urban expansion has led to encroachment and development on unstable slopes and unplanned construction and frequent violation of building by-laws and regulations. Significant areas of the city experience constant displacement due to the presence of relatively weak rock formations comprising of schists and phyllites. While some urban areas have been completely abandoned due to the structural damages in residential housing, schools, and office buildings, often these buildings are simply repaired or replaced.Gangtok is draped over several relatively steep hillsides. In this study, we have used synthetic aperture radar interferometry (InSAR) to understand the patterns of displacement better, highlighting areas prone to landslides. The rates of movement of these highly urbanized unstable areas have been measured using data collected by the Sentinel-1 satellites between 2015 and 2021. Field investigations have also confirmed the ongoing ground surface displacements shown in the InSAR results.Discretely bounded areas in Gangtok are moving at rates sometimes exceeding 12 cm/year. In this study, we concentrate our analysis on three landslide areas where people are residing: Tathenchen, Chanmari and Upper- and Lower-Sichey. In each of these areas, movement is continuous throughout the year. However, distinct periods of acceleration and deceleration are clearly linked to seasonal monsoon rainfall. For example, the velocity of the Upper Sichey landslide varies from about 3 cm/year to 7 cm/year, with peak velocity being reached shortly after peak precipitation each year. In addition, less than half of households in the region are connected to a wastewater network, resulting in significant amounts of water seeping into the local ground.The type of displacement information obtained by InSAR monitoring is helpful for developing effective mitigation strategies that can limit landslide damage. For example, while rainfall cannot be controlled, better drainage networks can mitigate the local effects. In a broader perspective, the data can be used within urban development planning to identify risk areas and monitor potential zones of catastrophic collapse.

Large slope collapses have been known to trigger extreme rushes of air loaded with projectiles (airblasts) capable of causing destruction and fatalities far beyond run-out of the rock mass. An appraisal of the likelihood of a destructive airblast should be a component of landslide risk assessments. Yet there is an absence of risk studies directly examining landslide-related airblasts. In this work we back-analyze an unreported airblast in the Sikkim Himalayas (India) and several other airblasts documented around the world. We explore the conditions a large slope collapse should meet to trigger a significant airblast, and we establish a semi-empirical relationship linking the potential energy in a collapse with airborne trajectory and the extent of the related airblast. The collapse of thousands or millions of cubic meters falling from a significant height results in a sudden release of energy (1011J to 1013J) and a high degree of comminution of rocks, causing a violent displacement of air. Average wind speeds of airblasts following impacts with airborne trajectory can be double the speed of rock avalanches. The size of the damage zone depends on the potential energy of the falling rock mass and can be amplified or reduced depending on how confined the valley is where the airblast occurs.

Interferometric processing of a time series of acquisitions from synthetic aperture radar (SAR) satellites makes it possible to detect and measure ground motion phenomena, typically caused by landslides, subsidence, earthquakes or volcanic activity, with millimeter-scale precision. This enables, for example, monitoring of the stability of slopes, mining areas, buildings and infrastructures. This work presents the European Ground Motion Service (EGMS), funded by the European Commission as an essential element of the Copernicus Land Monitoring Service (CLMS). The EGMS constitutes the first application of the interferometric SAR (InSAR) technology to high-resolution monitoring of ground deformations over an entire continent, based on full- resolution processing of all Sentinel-1 (S1) satellite acquisitions over most of Europe (Copernicus Participating States). Upscaling from existing national precursor services to pan-European scale is challenging. The EGMS will employ the most advanced persistent scatterer (PS) and distributed scatterer (DS) InSAR processing techniques in combination with a high quality Global Navigation Satellite System (GNSS) model to calibrate the ground motion products. To foster as wide usage as possible, the EGMS will also provide tools for visualization, exploration, analysis and download of the ground deformation products, as well as elements to promote best practice applications and user uptake., The EGMS project receives funding from the European Commission's Copernicus programme, under the European Environment Agency's framework service contract EEA/DIS/R0/20/011. The opinions expressed herein are only those of the authors and do not represent the official positions of the European Environment Agency.

Interferometric processing of series of data acquired over time by synthetic aperture radar (SAR) satellites makes it possible to measure millimetric ground motions (typically induced by landslides, subsidence and earthquake or volcanic phenomena), and to monitor the stability of buildings and infrastructures. In this work, we present the first application of the interferometric SAR (InSAR) technology to high-resolution monitoring of ground deformations over an entire continent, based on full-resolution processing of the whole archive of past and future Sentinel-1 (S1) satellite acquisitions over most parts of Europe. The European Ground Motion Service (EGMS) is funded by the European Commission and forms an essential element of the Copernicus Land Monitoring Service (CLMS) managed by the European Environment Agency. Upscaling from existing national precursor services to pan-European scale will be challenging. Although low-resolution datasets have been recently produced at this scale, full-resolution processing is more complex, potentially revealing errors that would be disguised or suppressed otherwise at coarser scale. The project will utilise the most advanced persistent scatterer (PS) and distributed scatterer (DS) InSAR processing techniques, and a high-quality GNSS model, required to calibrate the InSAR products. To foster acceptance and a maximum/optimum use of the service by the growing Copernicus user community and the public at large, the EGMS will provide tools for visualization, exploration, analysis and download of the ground deformation measurements, as well as elements to promote best practice and user uptake.

Rock avalanche clusters can be relevant indicators of the evolution of specific regions. They can be used to define: the type and intensity of triggering events, their recurrence and potential probability of occurrence, the progressive damage of the rock mass, the mechanisms of transport and deposition, as well as the environmental conditions at the time of occurrence. This paper tackles these subjects by analyzing two main clusters of rock avalanches (each event between 0.6 and 30 Mm 3 ), separated by few kilometers and located along the coastal scarp of Northern Chile, south of Iquique. It lies, hence, within a seismic area characterized by a long seismic gap that ended on April 1st, 2014 with a M w 8.2 earthquake. The scar position, high along the coastal cliff, supports seismic triggering for these clusters. The deposits' relative positions are used to obtain the sequence of rock avalanching events for each cluster. The progressive decrease of volume in the sequence of rock avalanches forming each cluster fits well the theoretical models for successive slope failures. These sequences seem to agree with those derived by dating the deposits with ages spanning between 4 kyr and 60 kyr. An average uplift rate of 0.2 mm/yr in the last 40 kyr is estimated for the coastal plain giving a further constraint to the rock avalanche deposition considering the absence of reworking of the deposits. Volume estimates and datings allow the estimation of an erosion rate contribution of about 0.098–0.112 mm km − 2 yr − 1 which is well comparable to values presented in the literature for earthquake induced landslides. We have carried out numerical modeling in order to analyze the mobility of the rock avalanches and examine the environmental conditions that controlled the runout. In doing so, we have considered the sequence of individual rock avalanches within the specific clusters, thus including in the models the confining effect caused by the presence of previous deposits. Bingham rheology was the most successful at explaining both the distance and the geometry of the observed events.

Source at https://doi.org/10.1016/j.rse.2016.12.024 It is well known that satellite radar interferometry (InSAR) is capable of measuring surface displacement with a typical accuracy on the order of millimeters to centimeters. However, when the true deformation vector differs from the satellite line-of-sight (LOS), the sensitivity decreases and interpretation of InSAR deformationmeasurements becomes challenging. By combining displacement data fromextensive ascending and descending TerraSAR-X datasets collected during the summer seasons of 2009–2014, we estimate two-dimensional (2D) InSAR surface displacement. Displacement data are decomposed into vertical and west/east deformation, dip and combined deformation vector, and validated using Global Navigation Satellite System (GNSS) data.We use the decomposed dataset to visualize variations in surface velocity and direction on unstable slopes in a periglacial environmentwith sporadic permafrost in northern Norway. By identifying areas with uplift and subsidence, and detecting velocity changes (downslope acceleration/deceleration) and related areas of extension and compression, we are able to explain driving and controlling mechanisms and geomorphology in two rockslides and one area with solifluction landforms.

The two-satellite Copernicus Sentinel-1 (S1) constellation became operational in Sep 2016, with the successful in-orbit commissioning of the S1B unit. During, the commissioning phase and early operational phase it has been confirmed that the interferometric performance of the constellation is excellent, with no observed phase anomalies. In this work, we show an analysis of selected performance parameters for the S1 constellation, as well as initial results based on the available data from the first months of operations.

World Landslide Forum (4º. 2017. Liubliana, Eslovenia), Exposure to hazards is expected to increase in Europe, due to rapid population growth in urban areas and the escalation of urbanization throughout many countries. In the framework of the European Geological Surveys (EGS), the Earth Observation and Geohazards Expert Group (EOEG) has carried out a survey based enquiry regarding the integration of geohazards (earthquakes, volcanoes, landslides, ground subsidence, floods and others) into urban and land-use planning. Responses from 19 European countries and 5 regions reveal heterogeneous policies across national borders. 17% of the countries have not yet implemented any legal measures to integrate geohazards into urban and land-use plans and half of the participating countries have no official methodological guides to construct geohazard maps. Additionally, there is a scarce knowledge about real social impacts of geohazards and resulting disasters in many of the countries, although they have a significant impact on their national economies. This overview stresses the need for a common legislative framework and homogenization of the national legislations as well as mutual guidelines which adopt the principles applicable to the management of geohazards and explain the process to be followed in the production of hazard documentation. This is especially relevant in case of landslide and subsidence hazards; although those are of great importance in Europe, there are no common guidelines and practices similar to Directive 2007/60/EC on the assessment and management of flood risk. Based on their expertise, EuroGeoSurveys (EGS) have the potential to coordinate this activity in European geohazard guidelines and to promote the interaction among stakeholders., Geohazards InSAR Laboratory and Modeling Group, Instituto Geológico y Minero de España, España, Bureau de Recherches Géologiques et Minières, Francia, Engineering Geology Department, Institute of Geology and Mineral Exploration, Grecia, GeoHazard team, Geological Institute of Romania, Rumanía, Geological Survey of Slovenia, Eslovenia, Croatian Geological Survey, Croacia, Geological Survey of Italy, Italia, Swiss Federal Office for the Environment, Suiza, Geological Survey of Austria, Austria, Polish Geological Institute, National Research Institute, Polonia, Geological Survey of Ireland, Irlanda, Czech Geological Survey, República Checa, Federal Institute for Geosciences and Natural Resources, Alemania, Geological Survey of Norway, Noruega, Cyprus Geological Survey, Chipre, Geological Survey of Sweden, Suecia, Institut Cartogràfic i Geològic de Catalunya, España, British Geological Survey, Reino Unido, Geological Survey of Slovakia, Eslovaquia, Geological Survey of Lithuania, Lituania, Federalni Zavod Za Geologiju, Nigeria, Geological Survey of Estonia, Estonia, Laboratorio Nacional de Energia e Minas, Portugal, Geological Survey of the Republic of Srpska, Bosnia y Herzegovina

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.

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.

Rockslides have a high socioeconomic and environmental importance in many countries. Norway is particularly susceptible to large rockslides due to its many fjords and steep mountains. One of the most dangerous hazards related with rock slope failures are tsunamis that can lead to large loss of life. It is therefore very important to systematically identify potential unstable rock slopes. Traditional landslide monitoring techniques are expensive and time consuming. Differential satellite interferometric synthetic aperture radar (InSAR) is an invaluable tool for land displacement monitoring. Improved access to time series of satellite data has led to the development of several innovative multitemporal algorithms. Small baseline (SB) methods are based on combining and inverting a set of unwrapped interferograms that are computed with a small perpendicular baseline in order to reduce spatial phase decorrelation. Another well proven technique is the persistent scatterer interferometric method (PSI) that is based on analysis of persistent point targets. In this paper, we apply both approaches to study several rockslide sites in Troms County in the far north of Norway. Moreover, we take the opportunity to address the difference and similarities between the SB and the PSI multitemporal InSAR methods for displacement studies in rural terrain.

Alpine topography in Norway is largely fault-controlled. Linear and asymmetric ranges developed in the footwalls of normal faults that were reactivated after the main phase of Mesozoic rifting, but prior to the Late Cenozoic glaciations. Stark geomorphological contrasts developed across the faults, reflecting differential glacial exploitation of the pre-glacial drainage pattern. Alpine topography developed preferentially in the footwalls. Triangular facets mark the traces of the most recently active faults. At the base of deeply incised, alpine range-front escarpments, the best-exposed faults display metres-thick fault-rock successions and record multiple phases of fault movement. Juxtaposition of Precambrian and Caledonian basement rocks with Jurassic or Cretaceous sedimentary rocks provides evidence for fault activity in or after the Mesozoic for some of the faults. Late Cretaceous or younger reactivation is indicated by jumps in apatite fission-track apparent ages across the faults, and interferometric synthetic aperture radar and earthquake data attest to normal faulting at the present day. Two of the areas described host anomalous clusters of rockslides that may relate to tectonic activity. The most distinct landscape-forming faults in western Scandinavia were probably active in the Cenozoic, and imposed asymmetric landscape patterns from the scale of single mountain ranges to the whole of Scandinavia.

Structural, geomorphic, and interferometric synthetic aperture radar (InSAR) surface displacement data show that uplift of the northernmost onshore Scandinavian passive margin is associated with active normal faulting and anomalous clusters of landslides. Regional-scale normal faults separate alpine footwall ranges with impressive range-front scarps from more gentle hanging-wall topography. In the Lyngen region, rockslides, sackung features (i.e., deep-seated slope gravitational deformation), and active faults cluster inside an ~1000 km 2 area of hanging-wall subsidence parallel to an ~30-km-long, faceted range-front scarp. From postglacial to recent time, rockslides have been released along the main range front and other propagating scarps, both in the footwall range and in structurally controlled, glacially oversteepened valleys of the hanging wall. The active rockslides, moving at rates of >10 mm/yr, show a variety of relationships to the controlling structures, reflecting tectonic as well as gravitational faulting. Recent and present-day landscape evolution and large-volume rockslide distribution in Scandinavia should be viewed from the perspective of tectonic processes involving active normal faults.

The present-day topography/bathymetry of the Norwegian mainland and passive margin is a product of complex interactions between large-scale tectonomagmatic and climatic processes that can be traced back in time to the Late Silurian Caledonian Orogeny. The isostatic balance of the crust and lithosphere was clearly influenced by orogenic thickening during the Caledonian Orogeny, but was soon affected by post-orogenic collapse including overprinting of the mountain root, and was subsequently affected by a number of discrete extensional events eventually leading to continental break-up in Early Eocene time. In the mid-Jurassic the land areas experienced deep erosion in the warm and humid climate, forming a regional paleic surface. Rift episodes in the Late Jurassic and Early Cretaceous, with differential uplift along major fault zones, led to more pronounced topographic contrasts during the Cretaceous, and thick sequences of clastic sediments accumulated in the subsiding basins on the shelf. Following renewed extension in the Late Cretaceous, a new paleic surface developed in the Paleocene. Following break-up the margin has largely subsided thermally, but several Cenozoic shortening events have generated positive contraction structures. On the western side of the on-shore drainage divide, deeper erosion took place along pre-existing weakness zones, creating the template of the present day valleys and fjords. In the Neogene the mainland and large portions of the Barents Sea were uplifted. It appears that this uplift permitted ice caps to nucleate and accumulate during the Late Pliocene northern hemisphere climatic deterioration. The Late Pliocene to Pleistocene glacial erosion caused huge sediment aprons to be shed on to the Norwegian Sea and Barents Sea margins. Upon removal of the ice load the landmass adjusted isostatically, and this still continues today.

Consequences of catastrophic rock slope failures (i.e. rock avalanches) are usually of large magnitude as they can run across large areas and can trigger secondary processes (e.g. displacement waves, river damming, valley flooding) that can produce large economic and life losses. Early detection of rock slope instabilities and definition of their hazard zones can help society to reduce the impact of these catastrophic failures. This contribution presents the results of the analysis done for an area in the Manndalen Valley, northern Norway. The site has been monitored by remote sensing techniques and the possible runout areas of a catastrophic failure have been defined using numerical modeling for three volume scenarios. Results show that the hazardous area is limited to the eastern valley flank and part of the valley bottom with no secondary processes triggered by the rock avalanche event.

Satellite and ground-based interferometric radars have the potential to measure the displacement of active rockslides. Data describing the spatial- and temporal displacement patterns of a rockslide are essential contributions to the total understanding of a rockslide. A better overview of the kinematics will in turn improve the quality of a risk assessment. In this study we have processed TerraSAR-X satellite data, collected since 2009, from both ascending and descending satellite tracks together with ground-based interferometric radar observations of an active rockslide in Northern Norway. Findings show that both the satellite and the ground-based data delimit the active rockslide area and that the displacement rates are highest in the upper part of the rockslide. In the lower parts of the rockslide, the displacement pattern shows a possible compressional toe-zone together with a fast moving lobate shaped landform.

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.

Systematic mapping of unstable rock slopes has been carried out in Norway since 2005. More than 300 unstable or potential unstable rock slopes have been detected and characterized so far. This utilises a standardized hazard and risk classification system that was established in 2012. The determination of the hazard and risk level follows a new standard approach for the systematic mapping of the analyzed sites that is iterative, starting with simple assessments. However the higher the hazard/risk level of a site is, the larger the amount of geological information collected, and the more detailed the run-out models and consequence analyses that will be carried out. This approach allows mapping resources to be focused on sites with higher risk level, delivering products with different levels of detail. Rock slope failures that would not result in any loss of life, as there is no life line or building in the run-out area, are mapped without a probability assessment. These analyses thus have no scale for the hazard class. Rock slope failures that can result in loss of life are analyzed using qualitative hazard analyses, thus the mapping products are hazard maps with qualitative probability classes. The work on this mapping approach is still ongoing; methods for assessment of the occurrence and consequences of secondary processes (e.g., triggering of displacement waves in water bodies, river damming and outburst floods) need still to be defined. An iterative approach will also be developed to analyze those processes.

Fennoscandia has experienced major uplift in postglacial time, which is assumed to reflect a glacial isostatic process connected to the melting of the last ice sheets. Extensive modelling of the isostatic movements show that the applied deglaciation and uplift model fit the observations well. There are, however, areas with significant deviations between uplift measurements and regional model predictions. The misfit between observations and the isostatic uplift modelling is interpreted here to reflect a tectonic component of the uplift. The objective of the present investigation is to isolate this tectonic uplift component. Interestingly enough, the areas found partly correspond to areas with pronounced seismic activity, and the assumption that the postglacial rebound is responsible for much of the observed onshore seismicity is substantiated. We conclude that there seems to be present-day deformation along the shoreline of mid-Norway, southern Norway (shoreline and mountain areas), and along the Swedish east coast with the centre northeast of the Gulf of Bothnia that cannot be explained by glacial isostasy. Not all of the deformations in these areas are necessarily co-seismic. The study suggests that such vertical deformations are small in magnitude and overprint the glacial rebound. The deformations may be a consequence of the Plio-Pleistocene erosional pattern, which is of glacial origin.

A systematic compilation and characterisation of many reports of neotectonic crustal deformation in Norway (both on local and regional scales) has identified two neotectonic faults in northern Norway. The Stuoragurra Fault is a large reverse fault in Finnmark County. The Nordmannvikdalen fault is a much smaller normal fault in Troms County. The Stuoragurra postglacial fault can be followed, in several discontinuous sections, for 80 km, in a NE–SW direction. The fault has up to 10 m of displacement. During 1998, two trenches were made across the fault. The hanging wall was seen to be thrust upwards over the footwall, with 7 m vertical displacement evident from displaced glacial contacts. The fault did not penetrate the overlying glacial materials, but rather folded them, forming a blind thrust. Large liquefaction and other deformation structures were found in the glaciofluvial sediments in both trenches. Veins of angular and subangular pebbles from the local bedrock penetrate more than 10 m laterally from the thrust plane and into the sediments in the footwall. It is thought that these veins were injected during the fault activity. The major deformation of the sediments has a decollement plane that continues laterally in the E/B horizon contact of the modern soil on top of the footwall. This may indicate that an initial pedogenesis had taken place before the fault activity occurred, however no macro plant fossils to support this were found in the possible buried soil. Deformational structures seen in the trench can be explained as a result of one major fault event. The Nordmannvikdalen postglacial fault is a NW–SE trending normal fault, dipping to the NE. The fault offsets till on the NW slope of Nordmannvikdalen. The escarpment varies in height from 0.5 to 1.5 m, with a trench often present between the hanging wall and the footwall. The fault locally splits into two subparallel branches, however this is probably only in the glacial overburden. Ground penetrating radar (GPR) profiles show two prominent bedrock reflectors, dipping approximately 40° to the NE. An upward extrapolation of the northernmost reflector through the overburden coincides with the position of the surface scarp. The bedrock is well exposed along a streamed parallel to the GPR profiles. Bedding and foliation cannot be responsible for the reflectors visible in the GPR profiles. Gravitational forces have been ruled out as the origin of the fault. Although both faults probably formed shortly after Weichselian deglaciation, there is evidence that isostatic uplift was not the only force acting. Quaternary tilting of Fennoscandia due to ridge push, or mantle convection, may also play a role in neotectonic activity in Norway.

The structural and geophysical characteristics of 2590–2580 Ma leucogranites in the northern Slave Province have been studied to determine the role and conditions of late Archean regional deformation during their emplacement. The irregularly shaped, straight sided, c. 10 km long Ulu pluton is located in the southern part of the High Lake greenstone belt, northern Slave Province. Fabrics in the pluton and its wall rocks indicate that it was emplaced at mid- to upper crustal levels during regional E–W late Archean compression. A gravity survey and resulting three-dimensional gravity model of the pluton show that it has several linear, deep (>6 km) root zones, which feed a relatively thin (

Historically, large rock slope failures impacting into a fjord and causing a several tens of metre high displacement wave have been one of the natural hazards in Norway claiming most lives. In the last 7 years, the Geological Survey of Norway has implemented a systematic mapping approach to characterize unstable rock slopes prone to catastrophic failures, so that future events can be recognized beforehand and society can adapt to the hazard. Systematic mapping has been carried out in three countries and more than 285 unstable slopes have been found. Of these sites, 62 are monitored periodically and 4 have been characterized as high risk objects with continuous monitoring systems installed. In order to classify the likelihood of a future event, rock slope mapping of each object includes the analyses of slide kinematic, velocity of the slide accompanied with other indicators of slide activity and an analysis of recurrence of previous events along the slope.

From studies of orthophotos and through field work, a complex deformation pattern has been recognized in the Lyngen area, Troms, Norway. The area is among the most alpine in Norway and contains a strong clustering of rock slope failures. The rock slope failures are characterized by two different deformation styles, and the difference in style is geographically separated by a fjord and valley lineament. Field studies suggest that two directions of tension oriented almost perpendicular to each other, utilize pre-existing brittle to brittle/ductile fabrics inherited from much older deformation events. The NE-SW direction of tension is parallel to the average displacement vector pointing down-dip along inherited faults. This vector is gravitationally controlled. The NW-SE displacement vector trends strike-parallel along the inherited faults. The presence of the latter appears to be confined geographically.

Strain analysis, observations of L-S fabrics and studies of the anisotropy of magnetic susceptibility (AMS) and of anisotropy of isothermal remanence (AIRM) reveal a sequence of progressive fabric development during regional deformation. L-S fabrics of quartz and feldspar grains are most transposed in regional transpression whereas the AMS subfabrics, controlled by the properties of late metamorphic silicates, record a later orientation of the ambient stress field. Anisotropy of magnetic remanence is caused by the still younger minerals, magnetite and pyrrhotite. Its anisotropy is less transposed than the AMS subfabric. Consequently the relative orientations of the three types of fabric yield a kinematic sequence of subfabrics developed during transpression. The L-S fabrics are most transposed, the AMS less transposed and the AIRM fabrics least transposed toward the plane of regional flattening. The results indicate that the deformation recorded by the three subfabrics was non-coaxial in the most general sense, with all three principal directions spinning with respect to the rocks during progressive straining.

The Archean metamorphic rocks of the Superior province of the Canadian Shield occur in lithologically defined belts or subprovinces. The tectonically more stable interiors of belts possess consistent primary components of magnetic remanence. In the case of the Quetico belt, these stable directions are tightly grouped about 005°/55° with some minor dispersion and most were acquired during the cooling that followed syntectonic recrystallisation. This study examines the directions of primary remanence components for rocks along the margins of the Quetico belt, within 4 km of the strongly deformed vertical, ENE-trending boundaries. The boundaries are known to have experienced dextral transpression involving penetrative single-phase deformation which out-lasted metamorphism. Within a few kilometres of the belt boundaries, the primary remanence components are re-distributed along a vertical ENE-trending, great-circle girdle which is nearly parallel to the plane of transpressive shear and regional schistosity. It is suggested that the effects of transpression have mechanically deflected the components of primary remanence toward this plane.

TOPO-EUROPE addresses the 4-D topographic evolution of the orogens and intra-plate regions of Europe through a multidisciplinary approach linking geology, geophysics, geodesy and geotechnology. TOPO-EUROPE integrates monitoring, imaging, reconstruction and modelling of the interplay between processes controlling continental topography and related natural hazards. Until now, research on neotectonics and related topography development of orogens and intra-plate regions has received little attention. TOPO-EUROPE initiates a number of novel studies on the quantification of rates of vertical motions, related tectonically controlled river evolution and land subsidence in carefully selected natural laboratories in Europe. From orogen through platform to continental margin, these natural laboratories include the Alps/Carpathians-Pannonian Basin System, the West and Central European Platform, the Apennines-Aegean-Anatolian region, the Iberian Peninsula, the Scandinavian Continental Margin, the East-European Platform, and the Caucasus-Levant area. TOPO-EUROPE integrates European research facilities and know-how essential to advance the understanding of the role of topography in Environmental Earth System Dynamics. The principal objective of the network is twofold. Namely, to integrate national research programs into a common European network and, furthermore, to integrate activities among TOPO-EUROPE institutes and participants. Key objectives are to provide an interdisciplinary forum to share knowledge and information in the field of the neotectonic and topographic evolution of Europe, to promote and encourage multidisciplinary research on a truly European scale, to increase mobility of scientists and to train young scientists. This paper provides an overview of the state-of-the-art of continental topography research, and of the challenges to TOPO-EUROPE researchers in the targeted natural laboratories. © 2007 Elsevier B.V. All rights reserved.

The European Plate Observing System (EPOS) aims to integrate existing infrastructures in the solid earth sciences into a single infrastructure, enabling earth scientists across Europe to combine, model, and interpret multidisciplinary datasets at different time and length scales. In particular, a primary objective is to integrate existing research infrastructures within the fields of seismology, geodesy, geophysics, geology, rock physics, and volcanology at a pan-European level. The added value of such integration is not visible through individual analyses of data from each research infrastructure; it needs to be understood in a long-term perspective that includes the time when changes implied by current scientific research results are fully realized and their societal impacts have become clear. EPOS is now entering its implementation phase following a four-year preparatory phase during which 18 member countries in Europe contributed more than 250 research infrastructures to the building of this pan-European vision. The Arctic covers a significant portion of the European plate and therefore plays an important part in research on the solid earth in Europe. However, the work environment in the Arctic is challenging. First, most of the European Plate boundary in the Arctic is offshore, and hence, sub-sea networks must be built for solid earth observation. Second, ice covers the Arctic Ocean where the European Plate boundary crosses through the Gakkel Ridge, so innovative technologies are needed to monitor solid earth deformation. Therefore, research collaboration with other disciplines such as physical oceanography, marine acoustics, and geo-biology is necessary. The establishment of efficient research infrastructures suitable for these challenging conditions is essential both to reduce costs and to stimulate multidisciplinary research.

Although Norway is situated along a passive continental margin, it is not devoid of tectonic activity. Several studies have documented significant movements along faults within the last 10-12 ka. Most of such movements probably occurred shortly after deglaciation, when rates of crustal rebound were very high. Nonetheless, current seismicity along the Norwegian coast suggests that crustal deformation is still taking place. Ranafjord, in northern Norway, is a region with higher than average seismic activity. A six-station seismic network installed by NORSAR detected numerous earthquake swarms in the area. In order to retrieve further crustal deformation data relative to Ranafjord it was decided to use differential SAR interferometry (DInSAR). The application of conventional DInSAR is extremely challenging because the expected deformation rates are low (a few mm/yr) and over long time spans phase coherence is not preserved on large portions of the area to be investigated. The Permanent Scatterers (PS) technique overcomes these drawbacks by exploiting long series of ERS data. At Permanent Scatterers, i.e. individual phase stable point-wise radar targets, displacement data can be retrieved with millimetric: accuracy. The PS grid can be seen as a high spatial density natural geodetic network. Thirty-seven ERS scenes covering the time span 1992-2000 were involved in a Permanent Scatterers (PS) analysis.

Unstable rock slopes that can cause large failures of the rock-avalanche type have been mapped in Norway for almost two decades. Five sites have been previously characterized as high-risk sites based on the expertise of a few researchers. Although more than 250 other sites are known, of which 90 are subjects of periodic displacement measurements, most have not been classified according to hazard or risk. A hazard and risk classification system for unstable rock slopes in Norway was established in 2012 with a related, targeted mapping approach adapted in 2013. This study presents the results of the hazard, consequence and risk classification of the first 22 unstable rock slopes, comprising 48 different failure scenarios from northern, western and southern Norway. These first 22 sites were selected based upon estimated highest risk levels and large attention in the Norwegian public. The hazard level of these 48 failure scenarios varies from low to very high, whereas their consequences range from 0 to 3000 possible casualties. The resulting risk classifications span from low to high risk.