Reginald L. Hermanns

Norwegian University of Science and Technology

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Ivanna Penna

Ramboll (Norway)

Martina Böhme

Norwegian Geological Survey

Bernd Etzelmüller

University of Oslo

Paula Hilger

Norwegian Geological Survey

Florence Magnin

Université Savoie Mont Blanc

Thierry Oppikofer

Terra Quantum (Switzerland)

John Gosse

Dalhousie University

John Dehls

Norwegian Geological Survey

Sebastian Westermann

University of Oslo

Samuel Niedermann

Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences

Cooperative Institutions

Norwegian Geological Survey

EuroGeoSurveys

Centre National de la Recherche Scientifique

University of Oslo

University of Iceland

United States Geological Survey

Norwegian University of Science and Technology

University of Buenos Aires

University of Lausanne

Université Savoie Mont Blanc

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Multiple rock-slope failures from Mannen in Romsdal Valley, western Norway, revealed from Quaternary geological mapping and ¹⁰Be exposure dating

The Holocene (2018)

Paula Hilger Reginald L. Hermanns John Gosse Benjamin Jacobs Bernd Etzelmüller

Oversteepened valley walls in western Norway have high recurrences of Holocene rock-slope failure activity causing significant risk to communities and infrastructure. Deposits from six to nine catastrophic rock-slope failure (CRSF) events are preserved at the base of the Mannen rock-slope instability in the Romsdal Valley, western Norway. The timing of these CRSF events was determined by terrestrial cosmogenic nuclide dating and relative chronology due to mapping Quaternary deposits. The stratigraphical chronology indicates that three of the CRSF events occurred between 12 and 10 ka, during regional deglaciation. Congruent with previous investigations, these events are attributed to the debuttressing effect experienced by steep slopes following deglaciation, during a period of paraglacial relaxation. The remaining three to six CRSF events cluster at 4.9 ± 0.6 ka (based on 10 cosmogenic 10 Be samples from boulders). CRSF events during this later period are ascribed to climatic changes at the end of the Holocene thermal optimum, including increased precipitation rates, high air temperatures and the associated degradation of permafrost in rock-slope faces. Geomorphological mapping and sedimentological analyses further permit the contextualisation of these deposits within the overall sequence of post-glacial fjord-valley infilling. In the light of contemporary climate change, the relationship between CRSF frequency, precipitation, air temperature and permafrost degradation may be of interest to others working or operating in comparable settings.

Deglaciation

Chronology

Cosmogenic nuclide

10.1177/0959683618798165

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Citations (41)

Earthquakes, subaerial and submarine landslides, tsunamis and volcanoes in Aysen Fjord, Chile

2014 AGU Fall Meeting (2014)

Galderic Lastras David Amblàs A. M. Calafat-Frau Miquel Canals Jaime Frigola

Subaerial

Fjord

10.13140/2.1.2219.2966

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Citations (0)

Evidence for propagating, active tensional faulting in Upper Kåfjord valley, Troms County, Norway

EGUGA (2010)

T.F. Redfield Per Terje Osmundsen I.H.C. Henderson Reginald L. Hermanns

Fjord

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SPLASH: semi-empirical prediction of landslide-generated displacement wave run-up heights

Geological Society London Special Publications (2018)

Thierry Oppikofer Reginald L. Hermanns Nicholas J. Roberts Martina Böhme

Abstract Displacement waves (or tsunamis) generated by sub-aerial landslides cause damage along shorelines over long distances, making run-up assessment a crucial component of landslide risk analysis. Although site-specific modelling provides important insight into the behaviour of potential waves, more general approaches using limited input parameters are necessary for preliminary assessments. We use a catalogue of landslide-generated displacement waves to develop semi-empirical relationships linking displacement wave run-up ( R in metres) to distance from landslide impact ( x in kilometres) and to landslide volume ( V in millions of cubic metres). For individual events, run-up decreases with distance according to power laws. Consideration of ten events demonstrates that run-up increases with landslide volume, also according to a power law. Combining these relationships gives the SPLASH equation: R = a V b x c , with best-fitted parameters a = 18.093, b = 0.57110 and c = −0.74189. The 95% prediction interval between the calculated and measured run-up values is 2.58, meaning that 5% of the measured run-up heights exceed the predicted value by a factor of 2.58 or more. This relatively large error is explained by local amplifications of wave height and run-up. Comparisons with other displacement wave models show that the SPLASH equation is a valuable tool for the first-stage preliminary hazard and risk assessment for unstable rock slopes above water bodies.

10.1144/sp477.1

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Citations (16)

Neotectonics in the foothills of the southernmost central Andes (37°–38°S): Evidence of strike‐slip displacement along the Antiñir‐Copahue fault zone

Tectonics (2004)

Andrés Folguera Víctor A. Ramos Reginald L. Hermanns José A. Naranjo

The Antiñir‐Copahue fault zone (ACFZ) is the eastern orogenic front of the Andes between 38° and 37°S. It is formed by an east vergent fan of high‐angle dextral transpressive and transtensive faults, which invert a Paleogene intra‐arc rift system in an out of sequence order with respect to the Cretaceous to Miocene fold and thrust belt. 3.1–1.7 Ma volcanic rocks are folded and fractured through this belt, and recent indicators of fault activity in unconsolidated deposits suggest an ongoing deformation. In spite of the absence of substantial shallow seismicity associated with the orogenic front, neotectonic studies show the existence of active faults in the present mountain front. The low shallow seismicity could be linked to the high volumes of retroarc‐derived volcanic rocks erupted through this fault system during Pliocene and Quaternary times. This thermally weakened basement accommodates the strain of the Antiñir‐Copahue fault zone, absorbing the present convergence between the South America and Nazca plates.

Neotectonics

Foothills

Transform fault

Strain partitioning

Thrust fault

10.1029/2003tc001533

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Citations (94)

Analyses of past and present rock slope instabilities in a fjord valley: Implications for hazard estimations

Geomorphology (2015)

Martina Böhme Thierry Oppikofer Oddvar Longva Michel Jaboyedoff Reginald L. Hermanns

Rockslide

Deglaciation

Frequency distribution

Fjord

Rockfall

10.1016/j.geomorph.2015.06.045

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Citations (45)

Permafrost distribution in steep slopes in Norway: measurements, statistical modelling and geomorphological implication

Florence Magnin Bernd Etzelmüller Sebastian Westermann Ketil Isaksen Paula Hilger

Abstract. Permafrost in steep slopes has been increasingly studied since the early 2000s in conjunction with a growing number of rock-slope failures, which likely resulted from permafrost degradation. In Norway, rock-slope destabilization is a widespread phenomenon and a major source of risk for the population and infrastructure. However, the lack of precise understanding of the permafrost distribution in steep slopes hinders the assessment of its role in these destabilizations. This study proposes the first nation-wide permafrost probability map for the steep slopes of Norway (CryoWall map). It is based on a multiple linear regression model fitted with multi-annual rock surface temperature (RST) measurements, collected at 25 rock-wall sites, spread across a latitudinal transect (59–69° N) over mainland Norway. The CryoWall map suggests that discontinuous permafrost widely occurs above 1300–1400 and 1600–1700 m a.s.l. in the north and south slopes of southern Norway (59° N), respectively. This lower altitudinal limit decreases in northern Norway (70° N) by about 500 ± 50 m, with more pronounced decrease for south faces, in reason of the insolation patterns largely driven by midnight sun in summer and polar night in winter. Similarly, the mean annual RST differences between north and south faces of similar elevation range around 1.5 °C in northern Norway and 3.5 °C in southern Norway. The CryoWall map is evaluated against direct ice observations in steep slopes and discussed in the context of former permafrost studies in various types of terrains in Norway. We show that permafrost can occur at much lower elevations in steep rock slopes than in other terrains, especially in north faces. We demonstrate that the CryoWall map is a valuable basis for further investigations related to permafrost in steep slopes in both practical concerns and fundamental science.

Elevation (ballistics)

10.5194/esurf-2018-90

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Citations (7)

Rock-avalanche deposit causes extreme high indoor radon concentrations in Kinsarvik, Ullensvang municipality, Western Norway

Engineering Geology (2023)

Jan Steinar Rønning Martina Böhme Ola Fredin Louise Hansen Reginald L. Hermanns

Bedrock

Cosmogenic nuclide

Uranium ore

Surface exposure dating

10.1016/j.enggeo.2023.107136

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Citations (1)

Rock avalanches in northeastern Baffin Island, Canada: understanding low occurrence amid high hazard potential

Landslides (2024)

Maureen C. Matthew John Gosse Reginald L. Hermanns Alexandre Normandeau T Tremblay

Abstract Rock avalanches in fjord environments can cause direct catastrophic damage and trigger secondary submarine landslides and tsunamis. These are well-documented in Greenland, Norway, and Alaska but have gone largely unreported in the extensive fjord terrain of the eastern Canadian Arctic. We provide the first inventory of rock avalanche deposits in northeastern Baffin Island—a region characterized by moderate to high seismic hazard, steep and high-walled fjords and glacial valleys, active deglaciation, and observed climate warming. Over a broad study area of ~60,000 km 2 , one sixth of the terrain had sufficient slope height and gradient to potentially generate rock avalanches. Within that hazard zone, we identified eight rock avalanche deposits at six locations. Only three rock avalanche deposits at two locations are dated, using aerial imagery (1958-present), to the last century while five deposits at four locations are inferred as syn- to post-glacial, likely occurring shortly after local debuttressing. These total numbers fall well below documented inventories from Greenland, Norway, and Alaska. We hypothesize that (1) continuous permafrost persists throughout this region and continues to act as a stabilizing factor and (2) rock mass quality is high in areas of most extreme relief contrast within the study region relative to analogous high-latitude fjord systems such as those in southwestern Greenland. We suggest that Baffin Island is currently in a period of quasi-stability that follows the intense instability during initial deglaciation, yet precedes the higher anticipated slope instability that may occur during permafrost degradation.

Natural hazard

10.1007/s10346-024-02315-8

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Citations (1)

Mega-deslizamientos de la pared sur del cerro Aconcagua y su relación con depósitos asignados a la glaciación pleistocena

Revista de la Asociación Geológica Argentina (2009)

Luis Enrique Fauqué Reginald L. Hermanns Kenneth Hewitt Mario Rosas Carlos G. J. Wilson

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Citations (20)