Geological model of the Åknes rockslide, western Norway

Ganerød, Guri V.; Grøneng, Guro; Rønning, Jan Steinar; Dalsegg, Einar; Elvebakk, Harald; Tønnesen, Jan Fredrik; Kveldsvik, Vidar; Eiken, Trond; Blikra, Lars Harald; Braathen, Alvar

doi:10.1016/j.enggeo.2008.01.018

Cited by 86 publications

(79 citation statements)

References 14 publications

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“…However, point based measurements provide only information on a few selected monitoring points and not on the whole landslide (Bitelli et al, 2004). The measured slope movements reach about 1-3 cm/year (Braathen et al, 2004;Derron et al, 2005;Kveldsvik et al, 2006;Ganerød et al, 2008), but higher annual displacements are recorded in the most unstable parts (7-20 cm/year) (Blikra et al, 2006b) (Fig. 1c).…”

Section: Introductionmentioning

confidence: 98%

“…Detailed investigations however revealed that the whole rockslide covers a much larger area (approximately 550 000 m 2 ) and stretches from 900 m down to 100 m above sea level . The new volume was estimated to T. Oppikofer et al: Characterization and monitoring ofÅknes rockslide by TLS Derron et al, 2005); (c) shaded relief map of the rockslide showing its extent, the location of the main scarp and the fast-moving ridge, as well as the annual displacement vectors in cm/year obtained by GPS (blue), extensometers (green) and total station (red) (displacement data from Ganerød et al (2008); ALS digital elevation model ©Åknes/Tafjord Project, 2005).…”

Section: Introductionmentioning

confidence: 99%

“…It is one of the biggest landslide monitoring projects in the world employing a multitude of geological, structural, geophysical and borehole investigations (Blikra et al, 2006a;Ganerød et al, 2008;Roth and Blikra, 2009). The monitoring focuses not only on the measurement of slope movements using a large variety of techniques (Kveldsvik et al, 2006), but also includes measurements of meteorological, seismic and groundwater conditions (Blikra et al, 2006a;Roth and Blikra, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Characterization and monitoring of the Åknes rockslide using terrestrial laser scanning

Oppikofer

Jaboyedoff

Blikra

et al. 2009

Nat. Hazards Earth Syst. Sci.

222

148

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Abstract. Terrestrial laser scanning (TLS) provides highresolution point clouds of the topography and new TLS instruments with ranges exceeding 300 m or even 1000 m are powerful tools for characterizing and monitoring slope movements. This study focuses on the 35 million m 3Å knes rockslide in Western Norway, which is one of the most investigated and monitored rockslides in the world. The TLS point clouds are used for the structural analysis of the steep, inaccessible main scarp of the rockslide, including an assessment of the discontinuity sets and fold axes. TLS acquisitions in 2006, 2007 and 2008 provide information on 3-D displacements for the entire scanned area and are not restricted like conventional survey instruments to single measurement points. The affine transformation matrix between two TLS acquisitions precisely describes the rockslide displacements and enables their separation into translational components, such as the displacement velocity and direction, and rotational components, like toppling. This study shows the ability of TLS to obtain reliable 3-D displacement information over a large, unstable area. Finally, a possible instability model for the upper part ofÅknes rockslide explains the measured translational and rotational displacements by a combination of southward planar sliding along the gneiss foliation, gravitational vertical settlement along the complex, stepped basal sliding surface and northward toppling toward the opened graben structure.

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Characterization and monitoring of the Åknes rockslide using terrestrial laser scanning

Oppikofer

Jaboyedoff

Blikra

et al. 2009

Nat. Hazards Earth Syst. Sci.

222

148

View full text Add to dashboard Cite

show abstract

“…Those studies combine classic geomorphological and geomechanical field mapping with various deformation monitoring techniques (e.g., Oppikofer et al, 2009;Booth et al, 2013;Wolter et al, 2014). Geophysical investigations provide links to the subsurface (e.g., Ganerød et al, 2008;Willenberg et al, 2008) and numerical modelling allows us to study the pre-and post-failure mechanisms (e.g., Stead et al, 2006;Gischig et al, 2011). Surface-exposure dating with terrestrial cosmogenic nuclides helps to show the temporal distribution and long-term slide velocities of rock-slope failures (e.g., Hippolyte et al, 2009;Hermanns et al, 2012bHermanns et al, , 2013.…”

Section: Introductionmentioning

confidence: 99%

Gravitational reactivation of a pre-existing post-Caledonian fault system: the deep-seated gravitational slope deformation at Middagstinden, western Norway

Schleier¹,

Hermanns²,

Krieger³

et al. 2016

NJG

Self Cite

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

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“…lower than 1000 m) characterizes clay-filled fractures and, consequently, also fault gouge (e.g. Ganerød et al, 2008). R.P.…”

Section: Resistivity Profilesmentioning

confidence: 99%

High resolution reflection seismic profiling over the Tjellefonna fault in the Møre-Trøndelag Fault Complex, Norway

2012

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Abstract. The Møre-Trøndelag Fault Complex (MTFC) is one of the most prominent fault zones of Norway, both onshore and offshore. In spite of its importance, very little is known of the deeper structure of the individual fault segments comprising the fault complex. Most seismic lines have been recorded offshore or focused on deeper structures. This paper presents results from two reflection seismic profiles, located on each side of the Tingvollfjord, acquired over the Tjellefonna fault in the southeastern part of the MTFC. Possible kilometer scale vertical offsets, reflecting large scale northwest-dipping normal faulting, separating the high topography to the southeast from lower topography to the northwest have been proposed for the Tjellefonna fault or the Baeverdalen lineament. In this study, however, the Tjellefonna fault is interpreted to dip approximately 50-60 • towards the southeast to depths of at least 1.3 km. Travel-time modeling of reflections associated with the fault was used to establish the geometry of the fault structure at depth, while detailed analysis of first P-wave arrivals in shot gathers, together with resistivity profiles, were used to define the near surface geometry of the fault zone. A continuation of the structure on the northeastern side of the Tingvollfjord is suggested by correlation of an in strike direction P-S converted reflection (generated by a fracture zone) seen on the reflection data from that side of the Tingvollfjord. The reflection seismic data correlate well with resistivity profiles and recently published near surface geophysical data. A highly reflective package forming a gentle antiform structure was also identified on both seismic profiles. This structure could be related to the folded amphibolite lenses seen on the surface or possibly by an important boundary within the gneissic basement rocks of the Western Gneiss Region. The fold hinge line of the structure is parallel with the Tjellefonna fault trace suggesting that the folding and faulting may have been related.

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Geological model of the Åknes rockslide, western Norway

Cited by 86 publications

References 14 publications

Characterization and monitoring of the Åknes rockslide using terrestrial laser scanning

Characterization and monitoring of the Åknes rockslide using terrestrial laser scanning

Gravitational reactivation of a pre-existing post-Caledonian fault system: the deep-seated gravitational slope deformation at Middagstinden, western Norway

High resolution reflection seismic profiling over the Tjellefonna fault in the Møre-Trøndelag Fault Complex, Norway

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