Regula Frauenfelder

• Perry, John; Waring, David; Frauenfelder, Regula; Anderson, Scott & Guimarães, Filipe (2026). Panel discussion on trends in geotechnical and geohazard risk management across infrastructure. Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards. ISSN 1749-9518. doi: 10.1080/17499518.2026.2691314. Full text in Research Archive Show summary

  Geotechnical and geohazard risk management is being reshaped by remote data, large data influx, integrated platforms, and earth observation. To highlight practical implications across mining, transportation, pipelines, communities, and the energy sectors, we synthesised an ISGSR 2025 panel discussion on trends in geotechnical and geohazard risk management across infrastructure. We used panel prompts, case studies, platform experience, and analogies to get our message across. Seven themes surfaced during the panel discussion: (1) decisions, not sensors, anchor practice; (2) remote methods excel at screening but rarely replace targeted field checks; (3) democratised InSAR creates opportunity yet also narrative risk; (4) integrated monitoring centres and roles improve traceability; (5) platforms and data integration compress time to decision; (6) distinguishing “what/where” from “how/why”; and (7) consequence, climate, and culture shape risk reduction. These findings led to a four-gate workflow – Screen, Triaged Field Check, Diagnose and Model, and Decide and Communicate. The panel recommends uncertainty-aware thresholds for gate transitions, human-in-the-loop alerting, provenance by design, and communication for public-facing products. The framework generalises across infrastructure classes but requires local calibration of tools, thresholds, and consequence criteria.

• Szakolczai, Stefano; Piciullo, Luca; Frauenfelder, Regula; Vöge, Malte; Carlà, Tommaso & Intrieri, Emanuele (2026). Forecasting the time of failure of tailings dams and Heap Leach Facilities through satellite InSAR data: myth or reality? Remote Sensing Applications: Society and Environment (RSASE). 42. doi: 10.1016/j.rsase.2026.101963. Full text in Research Archive
• Frauenfelder, Regula; Salazar, Sean; Paulsen, Eivind Magnus; Reutz, Elisabeth Hoffstad; Steinholt, Ingar Haug & Rødvand, Laura Anne [Show all 8 contributors for this article] (2025). Erosion detection and monitoring in quick clay areas by repeat UAV-borne LiDAR surveys: Two case studies from Norway. IOP Conference Series: Earth and Environmental Science (EES). ISSN 1755-1307. 1523(1). doi: 10.1088/1755-1315/1523/1/012039. Full text in Research Archive
• Lindsay, Erin Rose Pilaar; Ganerød, Alexandra Jarna; Devoli, Graziella; Reiche, Johannes; Nordal, Steinar & Frauenfelder, Regula (2025). Understanding Landslide Expression in SAR Backscatter Data: Global Study and Disaster Response Application. Remote Sensing. 17(19), p. 1–36. doi: 10.3390/rs17193313. Full text in Research Archive Show summary

  Cloud cover can delay landslide detection in optical satellite imagery for weeks, complicating disaster response. Synthetic Aperture Radar (SAR) backscatter imagery, which is widely used for monitoring floods and avalanches, remains underutilised for landslide detection due to a limited understanding of landslide signatures in SAR data. We developed a conceptual model of landslide expression in SAR backscatter (σ°) change images through iterative investigation of over 1000 landslides across 30 diverse study areas. Using multi-temporal composites and dense time series Sentinel-1 C-band SAR data, we identified characteristic patterns linked to land cover, terrain, and landslide material. The results showed either increased or decreased backscatter depending on environmental conditions, with reduced visibility in urban or mixed vegetation areas. Detection was also hindered by geometric distortions and snow cover. The diversity of landslide expression illustrates the need to consider local variability and multi-track (ascending and descending) satellite data in designing representative training datasets for automated detection models. The conceptual model was applied to three recent disaster events using the first post-event Sentinel-1 image, successfully identifying previously unknown landslides before optical imagery became available in two cases. This study provides a theoretical foundation for interpreting landslides in SAR imagery and demonstrates its utility for rapid landslide detection. The findings support further exploration of rapid landslides in SAR backscatter data and future development of automated detection models, offering a valuable tool for disaster response.

• Dupuy, Bastien; Grøver, Arnt; Garambois, Stéphane; Tobiesen, Finn Andrew; Lorand, Pauline & Dahle, Halgeir [Show all 11 contributors for this article] (2025). UAV-borne GPR for snowpack characterization: Potential, limitations and operational guidelines. Cold Regions Science and Technology. ISSN 0165-232X. 241, p. 1–23. doi: 10.1016/j.coldregions.2025.104641. Full text in Research Archive Show summary

  Characterization and monitoring of the snow cover is highly applicable for numerous problems in mountain and arctic environments, including avalanche hazard and hydrology assessments. Remote sensing techniques from space or air are conventionally used to map and monitor large areas. To bridge the gap between satellite and ground scales, we propose the use of UAV-borne GPR systems to optimize areal coverage, resolution and repeatability for snowpack information. We present an extensive study of the potential applications and limitations when using UAV-borne GPR for snowpack characterization. We discuss the operational constraints and demonstrate various examples conducted in different environments. We tested low (400 MHz) and high (1 GHz) frequency GPR systems on a commercial off-the-shelf UAV equipped with a radar altimeter and terrain following capabilities. GPR data were acquired at three field sites in central and western Norway. We demonstrate that data repeatability is satisfactory and that any measurement differences are due to aircraft positioning errors. We also tested data acquisition from various flight altitudes above the snow surface which led us to the conclusion that recording data between altitudes of 2 to 4 m above the surface is the best compromise between flight safety and data quality. Regarding flight speeds, if we focus on layer tracking and do not require high lateral resolution for discrete target mapping, data can be acquired at 2 m/s or more as long as flight safety is ensured. We recommend recording data along pre-determined flight paths, downslope starting from the highest elevation and following profiles parallel to the slope. Kinematic timelapse surveys recorded at a two-week interval highlighted the capabilities for thin layer detection. Centimeter thick melt-freeze crust layers are visible on GPR profiles and are correlated with observed layers in neighboring snowpits. Additional tests in wet snowpacks showed that the penetration depth was limited with the 1 GHz antenna due to the attenuation related to the presence of liquid water in the snowpack. The use of a lower frequency antenna (400 MHz) enabled sufficient penetration depth even though it caused a loss in resolution for mapping the upper layers of the snowpack. Overall, the UAV GPR surveys showed promising results towards recording highly repeatable snow height and snow layering data which can be helpful for avalanche forecasting and hydrology studies.

• Salazar, Sean; Hancock, Holt John; Frauenfelder, Regula; Dahle, Halgeir; Solbakken, Emil & Humstad, Tore (2024). Optimisation of UAV-borne lidar surveys for snow distribution mapping. International Snow Science Workshops (ISSW) Proceedings. Full text in Research Archive Show summary

  Laser scanners carried by uncrewed aerial vehicles (UAVs) have been proven to be effective data collection tools in mountainous terrain with relatively high spatial and temporal resolution. To determine the optimum data collection parameters for UAV-borne laser scanners, we performed a parametric analysis in avalanche terrain. Repeated test flights were executed with controlled variables, including flight altitude above terrain, flight speed, scanning pattern, and flight line orientation. The test flights were performed over complex terrain (a potential avalanche path) with snow cover. Analysis of the resulting datasets was used to determine the repeatability of the surveys as well as the sensitivity of each of the parameters on the resulting flight execution time and safety, measurement point density, and terrain/snow height models. The results of the analyses indicated that repeatability of flights was good, provided the aircraft maintained stable connection to a base station. Varying the flight parameters had significant effects on data collection time, point cloud density, and in some cases, the variability in measured terrain height. Notable findings also included the effect of navigation method on flight safety, and systematic errors and artifacts in the raw data. Only limited, independent accuracy checks were possible, due to the terrain and testing environment. We discuss implications that the present study’s findings pose for data capture in the context of operational mapping in avalanche terrain and provide general recommendations for effective snow height mapping using UAV-based laser scanning.

• Burn, Christopher R.; Bartsch, Annett; Chakraborty, Elora; Das, Soumik; Frauenfelder, Regula & Gärtner-Roer, Isabelle [Show all 30 contributors for this article] (2024). Developments in Permafrost Science and Engineering in Response to Climate Warming in Circumpolar and High Mountain Regions, 2019–2024. Permafrost and Periglacial Processes. ISSN 1045-6740. 0, p. 1–22. doi: 10.1002/ppp.2261. Full text in Research Archive Show summary

  Research in geocryology is currently principally concerned with the effects of climate change on permafrost terrain. The motivations for most of the research are (1) quantification of the anticipated net emissions of CO2 and CH4 from warming and thaw of near-surface permafrost and (2) mitigation of effects on infrastructure of such warming and thaw. Some of the effects, such as increases in ground temperature or active-layer thickness, have been observed for several decades. Landforms that are sensitive to creep deformation are moving more quickly as a result, and Rock Glacier Velocity is now part of the Essential Climate Variable Permafrost of the Global Climate Observing System. Other effects, for example, the occurrence of physical disturbances associated with thawing permafrost, particularly the development of thaw slumps, have noticeably increased since 2010. Still, others, such as erosion of sedimentary permafrost coasts, have accelerated. Geochemical effects in groundwater from trace elements, including contaminants, and those that issue from the release of sediment particles during mass wasting have become evident since 2020. Net release of CO2 and CH4 from thawing permafrost is anticipated within two decades and, worldwide, may reach emissions that are equivalent to a large industrial economy. The most immediate local concerns are for waste disposal pits that were constructed on the premise that permafrost would be an effective and permanent containment medium. This assumption is no longer valid at many contaminated sites. The role of ground ice in conditioning responses to changes in the thermal or hydrological regimes of permafrost has re-emphasized the importance of regional conditions, particularly landscape history, when applying research results to practical problems.

• Heyerdahl, Håkon; Amdal, Åse Marit Wist; Frauenfelder, Regula; Sverdrup-Thygeson, Kjetil & Lysdahl, Asgeir Olaf Kydland (2024). Forensic investigation of quick clay landslide released by construction work at Asak, Norway. In Guerra, Nuno; Fernandes, Manuel Matos; Ferreira, Cristiana; Correia, Antonio Gomes; Pinto, Alexandre & Pinto, Pedro Seco e (Ed.), Proceedings of the XVIII ECSMGE 2024 - Geotechnical Engineering Challenges to Meet Current and Emerging Needs of Society. CRC Press. ISSN 9781003431749. p. 1150–1153. doi: 10.1201/9781003431749-205. Full text in Research Archive
• McCormack, Edward; Humstad, Tore; Salazar, Sean; Frauenfelder, Regula; Dupuy, Bastien & Hendrikx, Jordy [Show all 8 contributors for this article] (2024). Operational integration of uncrewed aerial vehicles into roadway agencies' snow avalanche risk assessment process. International Snow Science Workshops (ISSW) Proceedings. Full text in Research Archive Show summary

  In Norway, as in other mountainous countries, snow avalanches pose a serious threat both to the users of their transport network and that system’s infrastructure. Road closures caused by avalanche danger or occurrence result in high economic costs and impact the reliability of Norway’s critical transport network. The Norwegian Public Roads Administration (NPRA) is responsible for maintaining important routes that are threatened by snow avalanches. Keeping these roads open requires expensive operations to assess and mitigate avalanche risk. The GEOSFAIR (Geohazard Survey from Air) project has explored the use of Uncrewed Aerial Vehicles (UAVs) for snow avalanche assessment to support the NPRA’s programs to keep critical mountain roadways open and safe. A three-year effort, GEOSFAIR was led by the NPRA in collaboration with the Norwegian Geotechnical Institute (NGI) and SINTEF research institutes. This effort focused on developing effective methodologies for integrating UAV technology and UAV-collected data into the present NPRA decision support system for avalanche risk assessment. The project has provided new and valuable information for decision-making and has developed guidance for roadway agency staff to assess avalanche risk using UAV data, including determining the effective use of UAV-carried sensors and cameras. A on-line table was created to relate snow, avalanche and terrain properties, important to the NPRA’s avalanche forecasting staff, to the capabilities and feasibility of UAV data collection. A detailed workflow for UAV operations by NPRA staff was developed by the project team. The team also demonstrated that effective avalanche data collection required operation in difficult weather and complex terrain, such that an occasional loss of aircraft and equipment damage will occur and should be accepted by roadway agencies operating avalanche programs

• Dupuy, Bastien; Chatel, Martin; Grøver, Arnt; Garambois, Stéphane; Lee, Madeline & Tobiesen, Finn Andrew [Show all 11 contributors for this article] (2024). UAV-borne ground penetrating radar for avalanche forecasting. International Snow Science Workshops (ISSW) Proceedings. Full text in Research Archive Show summary

  In the GEOSFAIR (Geohazard Survey from Air) innovation project for the Norwegian public sector, several UAV (Uncrewed Aerial Vehicles)-borne remote sensing payloads (LiDAR scanners; RGB, infrared, and multispectral cameras) were tested to gather information on the snow surface and its changes over time. For example, by comparing bare-earth and snow surface digital elevation models over time, it is possible to derive estimates of snow height and snow height changes. However, in addition to resolution limitations for snow height (which is dependent on the quality of baseline terrain models), none of these remote sensing methods can give information on the snow layering and snowpack properties. During the last three years, we tested UAV-borne GPR (Ground Penetrating Radar) sensors to get information on the subsurface of the snow, i.e., on snow height, snow layering and snow properties (snow density and liquid water content). Numerous field tests in real mountain conditions including mapping flat areas and BVLOS flights in avalanche starting zones enabled us to determine optimal operational flight guidelines. To optimize data quality, the GPR sensors should record data at an altitude less than 5 m above the snow surface, which requires altimeter and UAV terrain-following capabilities. Flying downslope at a speed up to 2-3 m/s and following the surface at 2-4 m have been shown to be the best compromise in terms of flight safety and data quality. In dry snowpacks, we use a shielded antenna with a 1 GHz central frequency, that penetrates up to 8-10 m of snow and can detect changes in layering down to a couple of centimeters. We show good correlations between snow pits and interpreted layers in the GPR data, especially when mapping melt-freeze crusts. By converting snow density to GPR wave velocity at a snow pit location, and by mapping snow surface and snow-ground interfaces, we are also able to derive high-resolution snow height maps which correlate well with snow height derived from LiDAR surveys with lower spatial resolution. UAV-borne GPR is a promising tool to provide remote snowpack information including high resolution snow height and snow layering and may be used to support local avalanche forecasting. Additional work is on-going to derive snow properties without the need for local snow pit information

• Kalsnes, Bjørn; Oen, Amy M P; Frauenfelder, Regula; Heggelund, Ingrid; Vasbotten, Marit & Vollstedt, Bente [Show all 12 contributors for this article] (2023). Stakeholder evaluation of the co-production process of climate services. Experiences from two case studies in Larvik (Norway) and Flensburg (Germany). Climate Services. 32. doi: 10.1016/j.cliser.2023.100409. Full text in Research Archive
• Tavakoli, Saman; Nicu, Ionut Cristi; Frauenfelder, Regula & Gilbert, Graham Lewis (2023). First geophysical investigations to study a fragile Pomor cultural heritage site at Russekeila – Kapp Linné), Svalbard. Journal of Cultural Heritage. ISSN 1296-2074. 63, p. 187–193. doi: 10.1016/j.culher.2023.08.005. Full text in Research Archive Show summary

  With climate warming, the cultural heritage sites of the Arctic are in great danger. Extensive research is needed to study such sites. The archaeological site at Russekeila – Kapp Linné, Svalbard was selected for the survey as previous research had highlighted its vulnerability to cryospheric hazards. The main objectives of the survey were (i) to register the precise surface and subsurface locations of cultural heritage (CH) (remains of an 18th century Russian Pomor trapper's hut) objects within the study area, (ii) to determine the impact of coastal erosion on the CH objects and (iii) to understand the near-surface stratigraphy of the site. The geophysical surveys were carried out using a Ground Penetrating Radar (GPR) instrument with two shielded antennas of 500 MHz and 800 MHz centre frequencies. Only weak anomalies were observed at the intersections with wooden drifts, which can be explained by the low contrast between the relative dielectric constant values of the driftwood and the background soil. The depth extent of the driftwood within the soil was understood from the processed GPR data to a depth of approximately 25 cm. A near-surface stratigraphy of the site morphology, including thaw depth, saturated and unsaturated sediments and soil cover, was established based on multiple reflectors observed to 2 m depth. Loose sediments are indicated by reflectors to a depth of approximately 20 cm. Unsaturated fine sediments, which show a stronger signal compared to the underlying saturated sand layers, can be observed from about 1.2 m depth. No reflectors are shown below the thaw depth.

• Buckel, Johannes; Mudler, Jan; Gardeweg, Rainer; Hauck, Christian; Hilbich, Christin & Frauenfelder, Regula [Show all 11 contributors for this article] (2023). Identifying mountain permafrost degradation by repeating historical electrical resistivity tomography (ERT) measurements. The Cryosphere. ISSN 1994-0416. 17(7), p. 2919–2940. doi: 10.5194/tc-17-2919-2023. Full text in Research Archive
• Lindsay, Erin; Frauenfelder, Regula; Ruther, Denise Christina; Nava, Lorenzo; Rubensdotter, Brita Lena Eleonor Fredin & Strout, James Michael [Show all 7 contributors for this article] (2022). Multi-Temporal Satellite Image Composites in Google Earth Engine for Improved Landslide Visibility: A Case Study of a Glacial Landscape. Remote Sensing. 14(10). doi: 10.3390/rs14102301. Full text in Research Archive Show summary

  Regional early warning systems for landslides rely on historic data to forecast future events and to verify and improve alarms. However, databases of landslide events are often spatially biased towards roads or other infrastructure, with few reported in remote areas. In this study, we demonstrate how Google Earth Engine can be used to create multi-temporal change detection image composites with freely available Sentinel-1 and -2 satellite images, in order to improve landslide visibility and facilitate landslide detection. First, multispectral Sentinel-2 images were used to map landslides triggered by a summer rainstorm in Jølster (Norway), based on changes in the normalised difference vegetation index (NDVI) between pre- and post-event images. Pre- and post-event multi-temporal images were then created by reducing across all available images within one month before and after the landslide events, from which final change detection image composites were produced. We used the mean of backscatter intensity in co- (VV) and cross-polarisations (VH) for Sentinel-1 synthetic aperture radar (SAR) data and maximum NDVI for Sentinel-2. The NDVI-based mapping increased the number of registered events from 14 to 120, while spatial bias was decreased, from 100% of events located within 500 m of a road to 30% close to roads in the new inventory. Of the 120 landslides, 43% were also detectable in the multi-temporal SAR image composite in VV polarisation, while only the east-facing landslides were clearly visible in VH. Noise, from clouds and agriculture in Sentinel-2, and speckle in Sentinel-1, was reduced using the multi-temporal composite approaches, improving landslide visibility without compromising spatial resolution. Our results indicate that manual or automated landslide detection could be significantly improved with multi-temporal image composites using freely available earth observation images and Google Earth Engine, with valuable potential for improving spatial bias in landslide inventories. Using the multi-temporal satellite image composites, we observed significant improvements in landslide visibility in Jølster, compared with conventional bi-temporal change detection methods, and applied this for the first time using VV-polarised SAR data. The GEE scripts allow this procedure to be quickly repeated in new areas, which can be helpful for reducing spatial bias in landslide databases.

• Frauenfelder, Regula; Lata, Matthew J. & Biskupič, Marek (2022). Snow Avalanche Detection and Mapping by Satellite Remote Sensing, IGARSS 2022 - 2022 IEEE International Geoscience and Remote Sensing Symposium. IEEE (Institute of Electrical and Electronics Engineers). ISSN 9781665427920. doi: 10.1109/IGARSS46834.2022.9884381. Full text in Research Archive
• Ekeheien, Christina Pokrie; Almestad, Christian; Frauenfelder, Regula; Heggelund, Ingerid & Oen, Amy M P (2022). Ny bydel i naturen – Hva har utbygging å si for fremtidig overvannssituasjon ved Martineåsen i Larvik kommune? Kart og Plan. ISSN 0047-3278. 115(2), p. 154–169. doi: 10.18261/kp.115.2.5. Full text in Research Archive
• Bohloli, Bahman; Berndt, Christian; Bjørnarå, Tore Ingvald; Bouquet, Sarah; Dujardin, Jean-Remi & Eiken, Ola [Show all 21 contributors for this article] (2022). Monitoring CO2 storage sites onshore and offshore using InSAR data and strain sensing fiber optics cables. SSRN Electronic Journal. Full text in Research Archive
• Ritter, Stefan & Frauenfelder, Regula (2021). InSAR monitoring data to assess building response to deep excavations. IOP Conference Series: Earth and Environmental Science (EES). ISSN 1755-1307. 710(012036). doi: 10.1088/1755-1315/710/1/012036. Full text in Research Archive
• Frauenfelder, Regula (2021). Remote Sensing in Geology. In Alderton, David & Elias, Scott A. (Ed.), Encyclopedia of Geology. Elsevier. ISSN 9780081029091. p. 736–745. doi: 10.1016/B978-0-08-102908-4.00170-3. Full text in Research Archive Show summary

  Remote sensing is the science of obtaining information about objects or areas from a distance, without being in direct contact with the target that's being investigated. Remote sensing methods make use of emitted and reflected radiation, captured from sensors on airplanes, satellites and drones, or from ground-based systems. Remote sensing exploits the fact that the Earth's atmosphere features three main atmospheric windows, each allowing the penetration of radiation. Active and passive methods are the two main types of remote sensing, utilizing naturally sourced radiation, or radiation actively produced by instruments, respectively. For decades, geologists have employed visual observations, photographs and, subsequently, aerial images to map and understand the Earths’ surface. Today, satellite imagery is used in addition to traditional methods or, sometimes, as a replacement. Recent advances in remote-sensing technologies, especially the rapid increase in the number of satellites, and consequently, in the image acquisition frequency, enable geoscientists to explore and analyze the land surface, acquire data and generate maps and evaluate the geo-potential of any specific area on the globe, at unprecedented scales and speeds. Today, remote sensing has become an irreplaceable tool in the geosciences at large, and specifically also in geology, the latter with many applications, such as geologic and geo-structural mapping, mineral and water exploration, hydrocarbon exploration, natural hazards analysis, and geomorphology.

• Tavakoli, Saman; Gilbert, Graham Lewis; Lysdahl, Asgeir Olaf Kydland; Frauenfelder, Regula & Forsberg, Cathinka Schaanning (2021). Geoelectrical properties of saline permafrost soil in the Adventdalen valley of Svalbard (Norway), constrained with in-situ well data. Journal of Applied Geophysics. ISSN 0926-9851. 195, p. 1–17. doi: 10.1016/j.jappgeo.2021.104497. Full text in Research Archive
• Pfaffhuber, Andreas Aspmo; Bazin, Sara & Frauenfelder, Regula (2020). Near-surface methods in the geotechnical industry: Challenges, opportunities and limitations. SEG Global Meeting Abstracts. ISSN 2159-6832. p. 20–23. doi: 10.1190/iceg2019-005.1. Full text in Research Archive Show summary

  The geological risk is a major unknown in large-scale infrastructure projects and frequently leads to cost overruns and major delays. Geophysics and remote sensing methods, when properly combined with traditional intrusive techniques, provide value to the geotechnical industry by reducing this risk. Continuous improvement of accuracy and resolution within both remote sensing and geophysics opens up to new innovative applications in the geotechnical industry. We present three examples. Integrating airborne electromagnetics and geotechnical drillings by virtue of machine learning provides dynamic, high-resolution depth of cover / bedrock topography 3D models. Various high-resolution ground geophysics methods identify buried objects that pose a risk to construction works. Finally, satellite-based radar interferometry with some mm / year accuracy provides project owners with settlement monitoring before, during and after construction works, supporting point measurements with traditional methods. Satellite-based, airborne, and ground-based methods have their individual strength and weaknesses. The challenges that projects encounter vary with different phases, thus the key to success is using the right method at the right time.

• Bazin, Sara; Lysdahl, Asgeir Olaf Kydland; Harstad, Andreas Olaus & Frauenfelder, Regula (2019). Resistivity and Induced Polarization (ERT/IP) survey for bedrock mapping in Permafrost, Svalbard. EarthDoc. doi: 10.3997/2214-4609.201902362. Full text in Research Archive
• Pfaffhuber, Andreas Aspmo; Bazin, Sara & Frauenfelder, Regula (2019). Near-Surface Methods in the Geotechnical Industry: Challenges, Opportunities and Limitations, 81st EAGE Conference and Exhibition 2019. European Association of Geoscientists and Engineers (EAGE). ISSN 9781510892811. doi: 10.3997/2214-4609.201901666. Full text in Research Archive Show summary

  The geological risk is a major unknown in large-scale infrastructure projects and frequently leads to cost overruns and major delays. Geophysics and remote sensing methods, when properly combined with traditional intrusive techniques, provide value to the geotechnical industry by reducing this risk. Continuous improvement of accuracy and resolution within both remote sensing and geophysics opens up to new innovative applications in the geotechnical industry. We present three examples. Integrating airborne electromagnetics and geotechnical drillings by virtue of machine learning provides dynamic, high-resolution depth of cover / bedrock topography 3D models. Various high-resolution ground geophysics methods identify buried objects that pose a risk to construction works. Finally, satellite-based radar interferometry with some mm / year accuracy provides project owners with settlement monitoring before, during and after construction works, supporting point measurements with traditional methods. Satellite-based, airborne, and ground-based methods have their individual strength and weaknesses. The challenges that projects encounter vary with different phases, thus the key to success is using the right method at the right time.

• Frauenfelder, Regula; Isaksen, Ketil; Lato, Matthew & Noetzli, Jeannette (2018). Ground thermal and geomechanical conditions in a permafrost-affected high-latitude rock avalanche site (Polvartinden, northern Norway). The Cryosphere. ISSN 1994-0416. 12(4), p. 1531–1550. doi: 10.5194/tc-12-1531-2018. Full text in Research Archive Show summary

  On 26 June 2008, a rock avalanche detached in the northeast facing slope of Polvartinden, a high-alpine mountain in Signaldalen, northern Norway. Here, we report on the observed and modelled past and present near-surface temperature regime close to the failure zone, as well as on a subsequent simulation of the subsurface temperature regime, and on initial geomechanical mapping based on laser scanning. The volume of the rock avalanche was estimated to be approximately 500 000 m3. The depth to the actual failure surface was found to range from 40 m at the back of the failure zone to 0 m at its toe. Visible in situ ice was observed in the failure zone just after the rock avalanche. Between September 2009 and August 2013, ground surface temperatures were measured with miniature temperature data loggers at 14 different localities, close to the original failure zone along the northern ridge of Polvartinden and on the valley floor. The results from these measurements and from a basic three-dimensional heat conduction model suggest that the lower altitudinal limit of permafrost at present is at 600–650 m a.s.l., which corresponds to the upper limit of the failure zone. A coupling of our in situ data with regional climate data since 1958 suggests a general gradual warming and that the period with highest mean near surface temperatures on record ended four months before the Signaldalen rock avalanche detached. A comparison with a transient permafrost model run at 10 m depth, representative for areas where snow accumulates, strengthen these findings, which are also in congruence with measurements in nearby permafrost boreholes. It is likely that permafrost in and near the failure zone is presently subject to degradation. This degradation, in combination with the extreme warm year antecedent to the rock failure, is seen to have played an important role in the detaching of the Signaldalen rock avalanche.

• Karlsrud, Kjell; Vangelsten, Bjørn Vidar & Frauenfelder, Regula (2017). Subsidence and shoreline retreat in the Ca Mau Province – Vietnam: Causes, consequences and mitigation options. Geotechnical Engineering. ISSN 0046-5828. 48(1), p. 26–32. Full text in Research Archive Show summary

  In the past decades, the Ca Mau province located at the southern end of Vietnam, has experienced significant land-loss. Satellite data suggest that a loss of land, or a retreat of the shoreline, ranging from about 100 m to 1.4 km have occurred over the past 20 years or so. In addition to the retreating coastline, the Ca Mau coastline has experienced loss of mangrove forests and saltwater intrusion into canals and rivers in the region. A study undertaken in collaboration between Vietnamese and Norwegian institutions has tentatively concluded that the main cause of the land-loss is subsidence of the ground surface as a result of ongoing groundwater pumping. The experienced land-loss may be further enhanced by a climate change related sea-level rise. Large parts of the land area in Ca Mau lie less than 1.5 m above sea-level. The subsidence settlements may already have reached 40 to 80 cm in some places, and the present subsidence rates may correspond to 2-4 cm/year. Recent satellite based data using InSAR technology (Interferometry Synthetic Aperture Radar) confirm that significant subsidence is ongoing in all provinces in Vietnam from Ho Chi Minh City and southwards. If no actions are taken soon, the implication will be that these provinces are lost to the sea within a time frame of a few decades. The only realistic way to prevent such subsidence settlements is to greatly reduce groundwater pumping in the area, and replace it with water from other sources. Also in light predicted climate-change related sea-level rise, some physical barriers may also be required to protect the region against flooding. It is recommended to immediately initiate an observational program and supplementary analyses to verify the present and future subsidence of the ground surface in Ca Mau. This is to ensure that remedial actions are planned for and implemented before it is too late.

• Malehmir, A.; Socco, L.V.; Bastani, M.; Krawczyk, C.M.; Pfaffhuber, Andreas Aspmo & Miller, R.D. [Show all 12 contributors for this article] (2016). Near-Surface Geophysical Characterization of Areas Prone to Natural Hazards: A Review of the Current and Perspective on the Future. Advances in Geophysics. ISSN 0065-2687. 57, p. 51–146. doi: 10.1016/bs.agph.2016.08.001. Full text in Research Archive Show summary

  Natural hazards such as landslides, floods, rockfalls, earthquakes, volcanic eruptions, sinkholes, and snow avalanches represent potential risks to our infrastructures, properties, and lives. That potential will continue to escalate with current and continued human encroachment into risk areas. With the help of geophysical techniques many of those risks can be better understood and quantified, thereby minimized and at least partly mitigated through accurate, site-specific, and proper planning and engineering. On occasions these hazards simply cannot be avoided, but better characterization and therefore understanding of the subsurface geology and natural processes responsible for the threats is possible through integration of various cost-effective geophysical methods with relevant geotechnical, geomechanical, and hydrogeological methods. With the enhanced characterization possible when geophysics is incorporated into natural hazard analysis, potential risks can be better quantified and remediation plans tuned to minimize the threat most natural hazards present to civilizations. In this article we will first review common geophysical methods that can be and have been utilized in studying natural hazard prone areas, then we provide selected case studies and approaches using predominantly our own examples, and finally a look into the future detailing how these methods and technologies can be better implemented and thereby more time- and cost-effective and provide improved results.

• Eckerstorfer, Markus; Bühler, Yves; Frauenfelder, Regula & Malnes, Eirik (2016). Remote sensing of snow avalanches: Recent advances, potential, and limitations. Cold Regions Science and Technology. ISSN 0165-232X. 121, p. 126–140. doi: 10.1016/j.coldregions.2015.11.001. Full text in Research Archive Show summary

  Snow avalanches are the main natural hazard in snow covered mountainous areas worldwide, frequently threatening lives and infrastructure. Avalanche research is inherently risk research, working towards avalanche risk mitigation and accident prevention. The pondering research questions have not changed much in the last decades; however, methods to approach these research questions have improved substantially. Remote sensing enables objective, safe, and spatial continuous observations of snow avalanches at different spatial scales. Today's abundance of sensor platforms and their sensitivity to a broad range of wavelengths allows for detection of avalanches and associated snowpack processes. This review paper highlights advancements in instrumentation, data analysis, and automatization efforts in detecting avalanches, applying ground based, air-, and space borne optical, laser and radar sensors. We further discuss opportunities and limitations of the instruments and techniques, as well as state where we see the most important future challenges. We focus on the applicability of the reviewed sensors and methods for avalanche detection and mapping in an operational context.

• Harbitz, Carl Bonnevie; Nakamura, Y.; Arikawa, Taro; Baykal, Cüneyt; Dogan, G.G. & Frauenfelder, Regula [Show all 20 contributors for this article] (2016). Risk assessment and design of prevention structures for enhanced tsunami disaster resilience (RAPSODI) - Euro-Japan collaboration. Coastal Engineering Journal (CEJ). ISSN 2166-4250. 58:1640012(4), p. 1–37. doi: 10.1142/S057856341640012X. Full text in Research Archive Show summary

  The 2011 Tōhoku event showed the massive destruction potential of tsunamis. The Euro-Japan “Risk assessment and design of prevention structures for enhanced tsunami disaster resilience (RAPSODI)” project aimed at using data from the event to evaluate tsunami mitigation strategies and to validate a framework for a quantitative tsunami mortality risk analysis. Coastal structures and mitigation strategies against tsunamis in Europe and Japan are compared. Failure mechanisms of coastal protection structures exposed to tsunamis are discussed based on field data. Knowledge gaps on failure modes of different structures under different tsunami loading conditions are identified. Results of the wave-flume laboratory experiments on rubble mound breakwaters are used to assess their resilience against tsunami impact. For the risk analysis, high-resolution digital elevation data are applied for the inundation modeling. The hazard is represented by the maximum flow depth, the exposure is described by the location of the population, and the mortality is a function of flow depth and building vulnerability. A thorough search for appropriate data on the 2011 Tōhoku tsunami was performed. The results of the 2011 Tōhoku tsunami mortality hindcast for the city of Ishinomaki substantiate that the tsunami mortality risk model can help to identify high-mortality risk areas and the main risk drivers.

• Bardi, Federica; Raspini, Federico; Ciampalini, Andrea; Kristensen, Lene; Rouyet, Line & Lauknes, Tom Rune [Show all 8 contributors for this article] (2016). Space-Borne and Ground-Based InSAR Data Integration: The Åknes Test Site. Remote Sensing. 8(3). doi: 10.3390/rs8030237. Full text in Research Archive Show summary

  This work concerns a proposal of the integration of InSAR (Interferometric Synthetic Aperture Radar) data acquired by ground-based (GB) and satellite platforms. The selected test site is the Åknes rockslide, which affects the western Norwegian coast. The availability of GB-InSAR and satellite InSAR data and the accessibility of a wide literature make the landslide suitable for testing the proposed procedure. The first step consists of the organization of a geodatabase, performed in the GIS environment, containing all of the available data. The second step concerns the analysis of satellite and GB-InSAR data, separately. Two datasets, acquired by RADARSAT-2 (related to a period between October 2008 and August 2013) and by a combination of TerraSAR-X and TanDEM-X (acquired between July 2010 and October 2012), both of them in ascending orbit, processed applying SBAS (Small BAseline Subset) method, are available. GB-InSAR data related to five different campaigns of measurements, referred to the summer seasons of 2006, 2008, 2009, 2010 and 2012, are available, as well. The third step relies on data integration, performed firstly from a qualitative point of view and later from a semi-quantitative point of view. The results of the proposed procedure have been validated by comparing them to GPS (Global Positioning System) data. The proposed procedure allowed us to better define landslide sectors in terms of different ranges of displacements. From a qualitative point of view, stable and unstable areas have been distinguished. In the sector concerning movement, two different sectors have been defined thanks to the results of the semi-quantitative integration step: the first sector, concerning displacement values higher than 10 mm, and the 2nd sector, where the displacements did not exceed a 10-mm value of displacement in the analyzed period.

• Frauenfelder, Regula; Solheim, Anders; Isaksen, Ketil; Romstad, Bård; Dyrrdal, Anita Verpe & Ekseth, Kristine [Show all 19 contributors for this article] (2016). Impacts of extreme weather events on transport infrastructure in Norway. Geophysical Research Abstracts. ISSN 1029-7006. Full text in Research Archive
• Kääb, Andreas; Frauenfelder, Regula & Sossna, Iris (2015). Glacier changes and permafrost distribution. In Sharma, Nayan & Flügel, Wolfgang (Ed.), Applied Geoinformatics for Sustainable Integrated Land and Water Resources Management (ILWRM) in the Brahmaputra River basin. Springer. ISSN 9788132219668. p. 25–30. doi: 10.1007/978-81-322-1967-5_6. Full text in Research Archive
• Frauenfelder, Regula; Lato, Matt & Biskupič, Marek (2015). Using eCognition to automatically detect and map avalanche deposits from the spring 2009 avalanche cycle in the Tatra Mts., Slovakia. International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences (ISPRS Archives). ISSN 1682-1750. XL-7/W3, p. 791–795. doi: 10.5194/isprsarchives-XL-7-W3-791-2015. Full text in Research Archive Show summary

  Here we present results from ongoing work where we apply an object oriented mapping algorithm developed in eCognition in order to automatically identify and digitally map avalanche deposits. The algorithm performance is compared with respect to a selected number of manually digitized avalanche outlines mapped by avalanche experts.

• Vöge, Malte; Frauenfelder, Regula; Ekseth, Kristine; Arora, Manoj K.; Bhattacharya, Atanu & Bhasin, Rajinder Kumar (2015). The use of SAR interferometry for landslide mapping in the Indian Himalayas. International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences (ISPRS Archives). ISSN 1682-1750. XL-7/W3, p. 857–863. doi: 10.5194/isprsarchives-XL-7-W3-857-2015. Full text in Research Archive Show summary

  The aim of the here presented research was to investigate the potential of two-pass differential InSAR, and advanced DInSAR techniques, such as Small Baseline Subset (SBAS) and Persistent Scatterers (PS) interferometry, in order to detect and monitor the temporal behaviour of surface deformations in selected areas of the Garhwal and Kumaon Himalaya. We present results from the surroundings of the town of Nainital, from the Mansa Devi Hills area, and the areas around the cities of Chamoli Gopeshwar and Joshimath.

• Racoviteanu, A.M.; Arnaud, Y.; Baghuna, I.M.; Bajracharya, S.R.; Berthier, E. & Bhambri, R. [Show all 17 contributors for this article] (2014). Himalayan Glaciers (India, Bhutan, Nepal): Satellite Observations of Thinning and Retreat. In Kargel, J.S.; Leonard, G.J.; Bishop, M.J.; Kääb, Andreas & Raup, B.H. (Ed.), Global Land Ice Measurements from Space. Springer. ISSN 9783540798170. p. 549–582. doi: 10.1007/978-3-540-79818-7_24. Full text in Research Archive
• Lato, Matt; Frauenfelder, Regula & Bühler, Y. (2012). Automated detection of snow avalanche deposits: segmentation and classification of optical remote sensing imagery. Natural Hazards and Earth System Sciences. ISSN 1561-8633. 12(9), p. 2893–2906. doi: 10.5194/nhess-12-2893-2012. Full text in Research Archive Show summary

  Snow avalanches in mountainous areas pose a significant threat to infrastructure (roads, railways, energy transmission corridors), personal property (homes) and recreational areas as well as for lives of people living and moving in alpine terrain. The impacts of snow avalanches range from delays and financial loss through road and railway closures, destruction of property and infrastructure, to loss of life. Avalanche warnings today are mainly based on meteorological information, snow pack information, field observations, historically recorded avalanche events as well as experience and expert knowledge. The ability to automatically identify snow avalanches using Very High Resolution (VHR) optical remote sensing imagery has the potential to assist in the development of accurate, spatially widespread, detailed maps of zones prone to avalanches as well as to build up data bases of past avalanche events in poorly accessible regions. This would provide decision makers with improved knowledge of the frequency and size distributions of avalanches in such areas. We used an object–oriented image interpretation approach, which employs segmentation and classification methodologies, to detect recent snow avalanche deposits within VHR panchromatic optical remote sensing imagery. This produces avalanche deposit maps, which can be integrated with other spatial mapping and terrain data. The object-oriented approach has been tested and validated against manually generated maps in which avalanches are visually recognized and digitized. The accuracy (both users and producers) are over 0.9 with errors of commission less than 0.05. Future research is directed to widespread testing of the algorithm on data generated by various sensors and improvement of the algorithm in high noise regions as well as the mapping of avalanche paths alongside their deposits.

• Frauenfelder, Regula & Isaksen, Ketil (2012). Ground Temperatures Near a Debris Slide Detachment zone in Signaldalen, Northern Norway. In Hinkel, Kenneth M. & Melnikov, Vladimir P. (Ed.), Proceedings of the Tenth International Conference on Permafrost : Salekhard, Yamal-Nenets Autonomous District, Russia June 25–29, 2012. The Northern Publishers (Severnoye Izdatelstvo). ISSN 9785905911019. doi: 10.5194/tc-2016-223. Full text in Research Archive
• Meyer, Nele Kristin; Dyrrdal, Anita Verpe; Frauenfelder, Regula; Etzelmuller, Bernd & Nadim, Farrokh (2012). Hydrometeorological threshold conditions for debris flow initiation in Norway. Natural Hazards and Earth System Sciences. ISSN 1561-8633. 12(10), p. 3059–3073. doi: 10.5194/nhess-12-3059-2012. Full text in Research Archive Show summary

  Debris flows, triggered by extreme precipitation events and rapid snow melt, cause considerable damage to the Norwegian infrastructure every year. To define intensity-duration (ID) thresholds for debris flow initiation critical water supply conditions arising from intensive rainfall or snow melt were assessed on the basis of daily hydro-meteorological information for 502 documented debris flow events. Two threshold types were computed: one based on absolute ID relationships and one using ID relationships normalized by the local precipitation day normal (PDN). For each threshold type, minimum, medium and maximum threshold values were defined by fitting power law curves along the 10th, 50th and 90th percentiles of the data population. Depending on the duration of the event, the absolute threshold intensities needed for debris flow initiation vary between 15 and 107 mm day−1. Since the PDN changes locally, the normalized thresholds show spatial variations. Depending on location, duration and threshold level, the normalized threshold intensities vary between 6 and 250 mm day−1. The thresholds obtained were used for a frequency analysis of over-threshold events giving an estimation of the exceedance probability and thus potential for debris flow events in different parts of Norway. The absolute thresholds are most often exceeded along the west coast, while the normalized thresholds are most frequently exceeded on the west-facing slopes of the Norwegian mountain ranges. The minimum thresholds derived in this study are in the range of other thresholds obtained for regions with a climate comparable to Norway. Statistics reveal that the normalized threshold is more reliable than the absolute threshold as the former shows no spatial clustering of debris flows related to water supply events captured by the threshold.

• Vöge, Malte; Frauenfelder, Regula & Larsen, yngvar (2012). Displacement monitoring at Svartevatn dam with interferometric SAR, Geoscience and Remote Sensing Symposium (IGARSS), 2012 IEEE International. IEEE Press. ISSN 9781467311601. p. 3895–3898. doi: 10.1109/igarss.2012.6350561. Full text in Research Archive
• Frauenfelder, Regula; Kronholm, Kalle; Solberg, Rune; Larsen, Siri Øyen; Salberg, Arnt Børre & Larsen, Jan Otto [Show all 7 contributors for this article] (2010). DUE avalRS: Remote-Sensing Derived Avalanche Inventory Data for Decision Support and Hind-Cast after Avalanche Events. In Lacoste-Francis, H. (Eds.), Proceedings of the ESA Living Planet Symposium. ESA Communications. ISSN 9789292212506. Full text in Research Archive Show summary

  Each year, snow avalanches hit populated areas and parts of the transport network in the Norwegian mountain regions, leading to loss of lives and the damaging of buildings and infrastructure. We present the results of a feasibility study on the operation of a service providing the National Public Roads Administration (NPRA) with hind-cast avalanche inventory data on a local-to-regional scale during the course of the winter season, and as soon as possible after major avalanche events. We have explored the use of imagery from high-resolution and very-highresolution space-borne satellites applying manual mapping and automated image segmentation.

• Harris, C; Arenson, L.U.; Christiansen, Hanne Hvidtfeldt; Etzemüller, B.; Etzelmuller, Bernd & Frauenfelder, R. [Show all 25 contributors for this article] (2009). Permafrost and climate in Europe: Monitoring and modelling thermal, geomorphological and geotechnical responses. Earth-Science Reviews. ISSN 0012-8252. 92(3-4), p. 117–171. doi: 10.1016/j.earscirev.2008.12.002. Full text in Research Archive Show summary

  We present a review of the changing state of European permafrost within a spatial zone that includes the continuous high latitude arctic permafrost of Svalbard and the discontinuous high altitude mountain permafrost of Iceland, Fennoscandia and the Alps. The paper focuses on methodological developments and data collection over the last decade or so, including research associated with the continent-scale network of instrumented permafrost boreholes established between 1998 and 2001 under the European Union PACE project. Data indicate recent warming trends, with greatest warming at higher latitudes. Equally important are the impacts of shorter-term extreme climatic events, most immediately reflected in changes in active layer thickness. A large number of complex variables, including altitude, topography, insolation and snow distribution, determine permafrost temperatures. The development of regionally calibrated empirical-statistical models, and physically based process-oriented models, is described, and it is shown that, though more complex and data dependent, process-oriented approaches are better suited to estimating transient effects of climate change in complex mountain topography. Mapping and characterisation of permafrost depth and distribution requires integrated multiple geophysical approaches and recent advances are discussed. We report on recent research into ground ice formation, including ice segregation within bedrock and vein ice formation within ice wedge systems. The potential impacts of climate change on rock weathering, permafrost creep, landslides, rock falls, debris flows and slow mass movements are also discussed. Recent engineering responses to the potentially damaging effects of climate warming are outlined, and risk assessment strategies to minimise geological hazards are described. We conclude that forecasting changes in hazard occurrence, magnitude and frequency is likely to depend on process-based modelling, demanding improved understanding of geomorphological process-response systems and their impacts on human activity.

• Etzelmuller, Bernd & Frauenfelder, Regula (2009). Factors Controlling the Distribution of Mountain Permafrost in the Northern Hemisphere and Their Influence on Sediment Transfer. Arctic, Antarctic and Alpine research. ISSN 1523-0430. 41(1), p. 48–58. doi: 10.1657/1938-4246(08-026)%5BETZELMUELLER%5D2.0.CO;2. Full text in Research Archive
• Frauenfelder, Regula; Kronholm, Kalle; Behling, Robert; Kääb, Andreas Max & Olsson, Rolf (2009). Combined use of optical remote sensing and GIS for the mapping of landslides triggered by the 2005 Kashmir earthquake, Pakistan. In Malingreau, Jean-Paul (Eds.), Proceedings, 33rd International Symposium on Remote Sensing of Environment, 4-8- May 2009, Stresa, Italy. International Center of Remote Sensing of Environment. p. 1–4. Full text in Research Archive
• Frauenfelder, Regula & Kääb, Andreas Max (2009). Glacier mapping from multi-temporal optical remote sensing data within the Brahmaputra river basin. In Malingreau, Jean-Paul (Eds.), Proceedings, 33rd International Symposium on Remote Sensing of Environment, 4-8- May 2009, Stresa, Italy. International Center of Remote Sensing of Environment. p. 1–4. Full text in Research Archive
• Janke, J & Frauenfelder, Regula (2008). The relationship between rock glacier and contributing area parameters in the Front Range of Colorado. Journal of Quaternary Science. ISSN 0267-8179. 23. doi: 10.1002/jqs.1133. Full text in Research Archive

View all works in NVA

• Lee, Madeline; McEnroe, Suzanne Amy; Dupuy, Bastien; Madriz, Yuleika; Gloaguen, Richard & Fareedh, Junaidh Shaik [Show all 12 contributors for this article] (2024). Drone measurement of subsurface magnetic and electromagnetic properties: Case Studies from Norway. Full text in Research Archive
• Dupuy, Bastien; Lee, Madeline; Chatel, Martin; Grøver, Arnt; Garambois, Stéphane & Dahle, Halgeir [Show all 11 contributors for this article] (2024). Snow measurements with UAV GPR tools. EAGE NSG 2024. Full text in Research Archive
• Dahle, Halgeir; Solbakken, Emil; Dupuy, Bastien; Humstad, Tore; Salazar, Sean & Frauenfelder, Regula (2023). Managing Natural Hazards by UAS. Full text in Research Archive
• Humstad, Tore; McCormack, E.; Frauenfelder, Regula; Salazar, Sean; Dupuy, Bastien & Hendrikx, Jordy (2023). Keeping winter roads open: Integrating snow avalanche risk assessment data from uncrewed aerial vehicles into roadway agencies' decision support systems. Full text in Research Archive Show summary

  Uncrewed aerial vehicles (UAVs) are increasingly used to monitor snow conditions. Routine operational use by roadway owning organisations for avalanche risk assessments require an understanding of UAV and sensor technology as well as of relevant organisational aspects. To investigate these areas, the Norwegian public-sector innovation project "Geohazard Survey from Air" (GEOSFAIR) is exploring remote decision support using UAVs. The effort has developed methodologies for effectively collecting and integrating UAV data into the decision support system for roadside avalanche risk assessments, helping keep critical roadways open and safe.

• Salazar, Sean; Frauenfelder, Regula; Humstad, Tore & Mccormack, Edward Donald (2023). Geohazard Monitoring by UAV: The Future Technology for Remote Decision Support. GEOSTRATA. ISSN 1529-2975. Full text in Research Archive
• Salazar, Sean; Dahle, Halgeir; Dupuy, Bastien; Frauenfelder, Regula; Grøver, Arnt & Humstad, Tore [Show all 11 contributors for this article] (2023). Multisensor UAS testing to support avalanche forecasting and monitoring. EAGE Conference and Exhibition. Full text in Research Archive
• Salazar, Sean; Frauenfelder, Regula & Smebye, Helge (2022). UAV Survey Methods for Geohazard Investigation, Modelling, and Monitoring. Full text in Research Archive
• Frauenfelder, Regula; Lato, Matthew & Biskupič, Marek (2022). Avalanche detection and mapping by satellite remote sensing. Full text in Research Archive
• Salazar, Sean; Paulsen, Eivind Magnus; Emhjellen, Linn Alexandra; Gauer, Peter; Frauenfelder, Regula & Smebye, Helge (2021). 3D modelling of an avalanche experiment using multi-platform remote observations. Full text in Research Archive
• Bohloli, Bahman; Park, Joonsang; Bjørnarå, Tore Ingvald; Sparrevik, Per; Frauenfelder, Regula & Vöge, Malte [Show all 10 contributors for this article] (2021). Monitoring ground surface and seafloor deformation caused by subsurface fluid injection. Full text in Research Archive
• Bohloli, Bahman; Bateson, Luke; Berndt, Christian; Bjørnarå, Tore Ingvald; Eiken, Ola & Estublier, Audrey [Show all 23 contributors for this article] (2021). Assuring Integrity of CO2 Storage Sites Through Ground Surface Monitoring (SENSE). SSRN Electronic Journal. doi: 10.2139/ssrn.3818971. Full text in Research Archive
• Frauenfelder, Regula; Vöge, Malte; Pfaffhuber, Andreas Aspmo; Hauser, Carsten; Dehli, Geir & Syversen, Fredrikke (2019). Settlement monitoring using space-borne radar interferometry, in the context of large infrastructure projects. In Society, The authors Icelandic Geotechnical (Eds.), Proceedings of the XVII ECSMGE 2019 : Geotechnical Engineering foundation of the future : European Conference on Soil Mechanics and Geotechnical Engineering. Icelandic Geotechnical Society. ISSN 9789935943613. doi: 10.32075/17ECSMGE-2019-0322. Full text in Research Archive Show summary

  Geodetic data acquisition in urban areas and along linear infrastructure are major cost drivers in big infrastructure projects. Modern remote sensing methods help us to manage data acquisitions with high effectiveness during the different phases of such projects. Here, we show how we apply space-borne radar interferometry to monitor settlements. We showcase two examples: a) the new E18-highway development project in Bærum, Norway; and b) the Follo Line railway project between Ski and Oslo. Monitoring is done by exploiting very high resolution TerraSAR-X data (ca. 1.5 x 1.5 m spatial ground resolution) in the E18 case, and high resolution Radarsat-2 data (ca. 7 x 7 m spatial ground resolution) in the Follo Line case. In both cases,

• Eidsvig, Unni & Frauenfelder, Regula (2019). Impact of adverse weather related events on terrestrial transportation lines. Geophysical Research Abstracts. ISSN 1029-7006. Full text in Research Archive
• Karlsrud, Kjell; Vangelsten, Bjørn Vidar & Frauenfelder, Regula (2016). Setninger som følge av grunnvannspumping- en udetonert bombe med større konsekvenser enn klimaendringer for mange land. Full text in Research Archive
• Malnes, Eirik; Eckerstorfer, Markus; Storvold, Rune; Frauenfelder, Regula & Jónsson, Árni (2014). SeFaS - Monitoring avalanches in Norway using SAR and UAV borne sensors. Full text in Research Archive
• Eckerstorfer, Markus; Malnes, Eirik; Frauenfelder, Regula; Domaas, Ulrik & Brattlien, Kjetil (2014). Avalanche debris detection using satellite-borne radar and optical remote sensing. Full text in Research Archive
• Malnes, Eirik; Eckerstorfer, Markus; Larsen, yngvar; Frauenfelder, Regula; Jónsson, Árni & Jaedicke, Christian [Show all 7 contributors for this article] (2013). Remote sensing of avalanches in northern Norway using Synthetic Aperture Radar. Full text in Research Archive
• Lato, Matt; Frauenfelder, Regula & Bühler, Y. (2012). Automated Avalanche Deposit Mapping From VHR Optical Imagery. Full text in Research Archive Show summary

  Using eCognition we developed an algorithm to automatically detect and map avalanche deposits in Very High Resolution (VHR) optical remote sensing imagery acquired from satellites and airplanes. The algorithm relies on a cluster-based object-oriented image interpretation approach which employs segmentation and classification methodologies to identify avalanche deposits. The algorithm is capable of detecting avalanche deposits of varying size, composition, and texture. A discrete analysis of one data set (airborne imagery collected near Davos, Switzerland) demonstrates the capability of the algorithm. By comparing the automated detection results to the manually mapped results for the same image, 33 of the 35 manually digitized slides were correctly identified by the automated method. The automated mapping approach characterized 201 667 m2, of the image as being representative of a fresh snow avalanche, roughly 8.5% of the image. Through a spatial intersection between the manually mapped avalanches and the automatically mapped avalanches, 184 432 m2, or 89%, of the automatically mapped regions are spatially linked to the manually mapped regions. The rate of false positive was less than 1% of the pixels in the image. The initial results of the algorithm are promising, future development and implementation is currently being evaluated. The ability to automatically identify the location and extent of avalanche deposits using VHR optical imagery can assist in the development of detailed regional maps of zones historically prone to avalanches. This in turn can help to validate issued avalanche warnings.

• Lato, Matt; Frauenfelder, Regula & Bühler, Yves (2012). Automated avalanche deposit mappping from vhr optical imagery. Full text in Research Archive
• Frauenfelder, Regula; Solberg, Rune; Larsen, Siri Øyen; Salberg, Arnt Børre & Bjordal, Heidi (2012). Remote-Sensing Derived Avalanche Inventory Data. Full text in Research Archive Show summary

  Every year snow avalanches pose a significant threat to transportation infrastructure. The societal demand to minimize closures of the main transport network while maintaining an acceptable level of personal safety at the same time has dramatically increased over the past decade. In Norway, decisions regarding avalanche warning, including pre-emptive road closure, are based on factors such as snow depth, meteorological conditions and expert opinion. The ability to automatically identify snow avalanches using very-high resolution optical imagery would greatly assist in the development of highly accurate, widespread, detailed maps of zones prone to avalanches. This would provide decision makers with better knowledge of previous events and details regarding the size and extent of historical events. We present the results of a ‘proof-of-concept’ study on the operation of a service providing the Norwegian Public Roads Administration (NPRA) with satellite data derived avalanche inventory data. We have explored the use of imagery from high-resolution and very-high-resolution space-borne satellites by developing and testing automated image segmentation and classification algorithms for the detection and mapping of avalanche deposits.

• Solberg, Rune; Frauenfelder, Regula; Larsen, Siri Øyen & Salberg, Arnt Børre (2012). Experiments with remote sensing in the context of avalanche warning and detection. Full text in Research Archive
• Salberg, Arnt Børre; Larsen, Siri Øyen; Frauenfelder, Regula & Solberg, Rune (2011). Automatic detection of avalanches in high resolution optical satellite data. Full text in Research Archive
• Frauenfelder, Regula; Kronholm, Kalle & Kääb, Andreas Max (2009). Combined use of optical remote sensing and GIS for landslide mapping. Full text in Research Archive
• Solberg, Rune; Frauenfelder, Regula; Koren, Hans & Kronholm, Kalle (2009). Could retrieval of snow layer formation by optical satellite remote sensing help avalanche forecasting? Presentation of first results. Full text in Research Archive
• Kääb, Andreas Max; Frauenfelder, Regula; Hoelzle, M.; Sossna, Iris & Avian, Michael (2009). Glacier, glacier lake and permafrost distribution in the Brahmaputra river basin. Full text in Research Archive
• Frauenfelder, Regula & Kääb, Andreas Max (2009). Glacier mapping from multi-temporal optical remote sensing data within the Brahmaputra River Basin. Full text in Research Archive
• Kääb, Andreas Max; Frauenfelder, Regula & Kronholm, Kalle (2009). Combined use of optical remote sensing and GIS for landslide mapping: example from Pakistan. Full text in Research Archive
• Frauenfelder, Regula; Tolgensbakk, Jon; Farbrot, Herman & Lauknes, Tom Rune (2008). Rockglaciers in the Kåfjord Area, Troms, Northern Norway. Full text in Research Archive
• Kääb, Andreas Max & Frauenfelder, Regula (2008). Glacier distribution and glacier area changes 1960s-2000 in the Brahmaputra river basin. Full text in Research Archive
• Dyrrdal, Anita Verpe; Bakke, Sigrid Jørgensen; Hanssen-Bauer, Inger; Mayer, Stephanie; Nilsen, Irene Brox & Nilsen, Jan Even Øie [Show all 71 contributors for this article] (2025). Klima i Norge – kunnskapsgrunnlag for klimatilpasning oppdatert i 2025. Meteorologisk institutt. Full text in Research Archive Show summary

  I kjølvannet av FNs klimapanels sjette hovedrapport, og nedskalerte europeiske klimaframskrivninger, har Norsk klimaservicesenter fått i oppdrag å oppdatere rapporten Klima i Norge – Kunnskapsgrunnlag for klimatilpasning oppdatert i 2025. Dette er den tredje utgaven av ”Klima i Norge”-rapporten. Klima i Norge beskriver hvordan klimaendringer påvirker Norge, basert på målinger og klimaframskrivninger. Rapporten omhandler primært nasjonale forhold og definerer klimaendringer som endringer i atmosfære, kryosfære, hydrologi, skred og hav. Denne kunnskapen danner grunnlaget for klimatilpasning i Norge

• Humstad, Tore; McCormack, Edward; Frauenfelder, Regula; Dupuy, Bastien; Dahle, Halgeir & Salazar, Sean [Show all 7 contributors for this article] (2025). GEOSFAIR – Geohazard Survey from Air: Innovation project for the public sector (2021–2024) - Final report. Statens vegvesen. Full text in Research Archive Show summary

  The research effort, GEOSFAIR, developed effective methodologies for integrating uncrewed aircraft systems (UASs - which include aircraft, sensors, and flight operations software) and UAS-collected data into the present Norwegian Public Roads Administrations (NPRA) decision support system for geohazard risk assessment. This effort considered both decision-making requirements and UAS aircraft, sensors, and software specifications. The goals addressed as part of GEOSFAIR included the following: • Identify and evaluate UASs that are suitable for NPRA's geohazard applications. • Specify requirements for adoption of UAS by decision makers within the NPRA and by other road owners and transportation organizations. • Test UASs and UAS collected data under realistic field conditions and first evaluation of results. • Develop software and tools that provide usable information and allow rapid integration and support of UAS operations and data into the NPRA decisionmaking processes. The specific tasks completed as part of GEOSFAIR were as follows: • Identified UAS requirements. • Made recommendations for sensor technologies. • Automated mission execution. • Automated data processing workflow. • Created 3D rendering and an application programming interface (API) plug-in for the resulting data. • Consolidated requirements for UAS use. • Tested UASs under field conditions. • Interpretated and validated the data. • Developed decision support philosophies. • Developed data management and utilization. • Developed organizational requirements. • Identified other geohazard applications. • Documented and disseminated results. The following were the guiding research questions of GEOSFAIR: • How UASs provide data in support of roadside avalanche monitoring. • Whether UASs provide data replacement or just enhance existing tools that the NPRA currently employ. GEOSFAIR – Geohazard Survey from Air (2021 – 2024): Final report 5 • Whether UAS operations provide useful and timely coverage in locations of avalanche hazard. • How UASs can be used operationally in steep terrain and in a range of lighting and weather conditions. • How UASs can be operated remotely and fly autonomously to gather data. • How new technology can be successfully and economically integrated with the NPRA’s current decision-making processes. The following are the conclusions drawn from GEOSFAIR: • UASs can be successfully operated by the NPRA. • Both real-time kinematics (RTK) and non-RTK positioning systems for flying UASs are needed. • The NPRA does not need to design its own software or other tools. • Sensors are useful, with the most useful being cameras and photogrammetry, but lidar and ground penetrating radar are also useful. • The findings suggest that all the NPRA’s geohazard experts should be UAS pilots. • Drone garages will be useful to the NPRA. • Operation and Maintenance contractors hired by the NPRA should have UAS pilots and equipment.

• Humstad, Tore; McCormack, Edward; Frauenfelder, Regula; Dupuy, Bastien; Dahle, Halgeir & Salazar, Sean [Show all 7 contributors for this article] (2025). GEOSFAIR - Geohazard Survey from Air: Innovation project for the public sector (2021-2024) - Final report. Statens vegvesen. Full text in Research Archive Show summary

  Prosjektet GEOSFAIR har utviklet metoder for å innlemme droner med sensorer i Statens vegvesen sitt system for beslutning om snøskredfare. Teknologien er testet under realistiske feltforhold, programvare og arbeidsmetodikk er utviklet. Det er gitt anbefalinger om bruk av kamera (for fotogrammetri), lidar og georadar (GPR). Droner gir nyttig og tidsriktig data for skredvurdering, og de kan erstatte enkelte helikopteroppdrag. Teknologien bidrar til bedre beslutninger, økt sikkerhet og styrket beredskap. Det anbefales videre utvikling av fjernassisterte og fjernstyrte droneoperasjoner, autonomi og bruk ved flere typer naturfarer.

• Chatel, Martin; Dupuy, Bastien; Lee, Madeline; Grøver, Arnt; Salazar, Sean & Frauenfelder, Regula [Show all 8 contributors for this article] (2025). Snowpack mapping with georadar (GPR) on UAS: Quantitative analysis of GPR data for snowpack properties. Statens vegvesen. Full text in Research Archive Show summary

  As part of the GEOSFAIR project (2021-2024), methods were developed to derive quantitative snowpack information from GPR data captured by UAS. An automatic picking algorithm was implemented to identify snow surface and snow-ground interfaces. Using a dense dataset with GPR lines every 50 cm recorded at Fonnbu in March 2024, travel times were converted to snow heights and compared with UAS-based LiDAR survey results. Different bare ground models were used for LiDAR snow heights. Additionally, a machine learning algorithm was tested to derive snow density from UAS GPR data, showing promising results when tested on real data from 2022-2024.

• Solbakken, Emil; Dahle, Halgeir; Humstad, Tore & Frauenfelder, Regula (2025). Droneoperasjoner ved skredutsatt veg: Forslag til organisering og videre utvikling. Statens vegvesen. Full text in Research Archive Show summary

  Rapporten er utarbeidet som del av forskningsprosjektet GEOSFAIR og tar for seg hvordan vegeiere best kan utnytte droner i håndteringen av skred og skredfare. Det foreslås noen utvalgte tiltak som har som mål å (1) sikre at vi har droner og piloter i nærheten av der skredene går, (2) forbedre datakvaliteten og (3) øke bruken av droner i aktive og organisatoriske sikringstiltak. En satsing på disse områdene vil ikke bare kunne føre til raskere og bedre beslutninger etter at skredet har truffet veg, men også gi vegeiere helt nye muligheter for overvåkning og tidlig varsling.

• Tobiesen, Finn Andrew; Reutz, Elisabeth Hoffstad; Salazar, Sean; Dupuy, Bastien; Dahle, Halgeir & Grøver, Arnt [Show all 10 contributors for this article] (2024). Quality of photogrammetry and LiDAR from UAS. Statens vegvesen. Full text in Research Archive Show summary

  This report summarizes comparative studies of repeatability and accuracy of optical and laser data recorded with UAS mounted sensors. For photogrammetry surveys, different sensors, different processing software has been used. The overall conclusions and findings of this work are that both photogrammetry and lidar surveys may give accurate elevation models and orthomosaic using high-end survey drones with current available processing software. We conclude that with this type of technology will be useful and valuable as a part of an integrated workflow for avalanche forecasting.

• McCormack, Edward; Dahle, Halgeir; Dupuy, Bastien; Frauenfelder, Regula; Hellandsvik, Are & Hendrikx, Jordy [Show all 10 contributors for this article] (2024). State of the Art Review: Avalanche Hazard Assessment Supported by UAS. Statens vegvesen. Full text in Research Archive
• Tobiesen, Andrew; Dahle, Halgeir; Dupuy, Bastien; Salazar, Sean; Frauenfelder, Regula & Grøver, Arnt [Show all 9 contributors for this article] (2024). Photogrammetry and LiDAR from UAS in steep terrain. Statens vegvesen. ISSN 9788272077180. Full text in Research Archive Show summary

  This report describes procedures and recommendations for acquisition of remote sensing data over snow surfaces. It includes survey planning and data processing routines for high resolution terrain mapping using optical cameras and LiDAR scanning methods, both using commercial and open-source tools.

• Tregaskis, Callum; Jaedicke, Christian; Gauer, Peter; Gisnås, Kjersti Gleditsch; Robinson, Kate & Issler, Dieter [Show all 9 contributors for this article] (2023). Research Plan 2023–2025. Norges Geotekniske Institutt. Full text in Research Archive Show summary

  Snow avalanches are a frequent and significant natural hazard in Norway. Each year, avalanche events result in fatalities, evacuations, interruptions, and damage to infrastructure networks such as roads, railways, and electrical transmission lines. This combines to a substantial impact on the livelihoods of the people living and working in mountainous areas or also along the fjords in Norway. Persistent avalanche hazard in steep terrain is a major factor considered during land-use planning and development. During the snow season, variations in the avalanche danger identified in regional and site-specific bulletins influence the operation of the transportation networks and the safety of workers in these areas. Applied research on avalanches and their societal impacts has been conducted at the Norwegian Geotechnical Institute (NGI) since 1973. The year 2023 will mark the 50 years anniversary of this research project. The research has been funded in part by an annual grant from the Norwegian parliament administered by the Norwegian Water Resources and Energy Directorate (NVE). Recent research activities have improved our understanding of avalanche formation, movement and impacts from avalanches. For example, enhanced knowledge of the individual processes leading to avalanche initiation, avalanche dynamics and avalanche impacts have been applied to develop tools for prediction of avalanche events, runout distance and impact pressures. While much has been accomplished within the avalanche research community in recent years, many key questions remain. Research in this area becomes increasingly important as a changing climate will vary the frequency and behaviour of avalanche events. In addition, the transfer of resent research outcomes into common practise is an ongoing challenge which needs continuous attention. This project plan will: Present the research goals for the 2023–2025 period. Outline the project organisation. Present the work-package structure and specific research tasks to be undertaken by the applied avalanche research group at NGI over the next three years.

• Frauenfelder, Regula; Salazar, Sean; Dahle, Halgeir; Humstad, Tore; McCormack, Edward & Solbakken, Emil [Show all 11 contributors for this article] (2022). Field test of UAS to support avalanche monitoring: Field test activity report - Fonnbu March 2022. Statens vegvesen. Full text in Research Archive
• Reutz, Elisabeth Hoffstad; Frauenfelder, Regula & Salazar, Sean (2022). GEOSFAIR – Geohazard Survey from Air: Consolidation of requirements - Analysis of questionnaire. Norges Geotekniske Institutt. Full text in Research Archive
• McCormack, Edward; Solbakken, Emil; Humstad, Tore; Dahle, Halgeir; Vaa, Torgeir & Andreassen, Dag Theodor [Show all 10 contributors for this article] (2022). Lidar on UAS to support avalanche monitoring: Findings from demonstration in Trollstigen, October 2021. Statens vegvesen. Full text in Research Archive
• Frauenfelder, Regula & Moldestad, Dag Anders (2020). CO2 storage site monitoring with InSAR. Norsk Romsenter. Full text in Research Archive
• Bohloli, Bahman; Sparrevik, Per; Vöge, Malte; Frauenfelder, Regula; Park, Joonsang & Berndt, Christian [Show all 10 contributors for this article] (2020). Quantification of ground movement. State-of-the-art. NGI (Norges Geotekniske Institutt). Full text in Research Archive
• Bilt, Willem van der; Bakke, Jostein; Smedsrud, Lars H.; Sund, Monica; Schuler, Thomas & Westermann, Sebastian [Show all 47 contributors for this article] (2019). Climate in Svalbard 2100. Norsk klimaservicesenter. Full text in Research Archive Show summary

  This report was commissioned by the Norwegian Environment Agency in order to provide basic information for use in climate change adaptation in Svalbard. It includes descriptions of historical, as well as projections for the future climate development in the atmosphere, hydrosphere, cryosphere and ocean, and it includes effects on the physical nature e.g. on permafrost and various types of landslides and avalanches. The projections for the future climate are based on results in the IPCCs fifth assessment report. The report is to a large degree an assessment of existing literature and model results. New results from atmosphere, ocean and hydrological models are, however, also presented.

• Frauenfelder, Regula; Kaiser, Gunilla; Harbitz, Carl Bonnevie; Glimsdal, Sylfest; Liu, Zhongqiang & Cepeda, Jose [Show all 9 contributors for this article] (2017). GeoRisk Assessment and Management (GRAM). Subproject 4.3: Climate adaptation in risk and vulnerability analysis. NGI. Full text in Research Archive
• Frauenfelder, Regula; Kronholm, Kalle; Solberg, Rune; Salberg, Arnt Børre & Larsen, Siri Øyen (2011). Service Implementation Document – Deliverable 3. ESA project report, AvalRS, ESRIN/Contract No. 22139/08/I-EC. European Space Agency. Full text in Research Archive

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