Mass Movement in Bedrock

Brideau, Marc-André; Roberts, Nicholas J.

doi:10.1016/b978-0-12-396452-6.00003-3

Cited by 7 publications

(11 citation statements)

References 253 publications

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“…This definition is used here to distinguish RSF from 'rockfall'the smaller-scale process involving the piecemeal detachment and free fall of individual rock particleseven though the term rockfall is commonly used at all scales, including the largest landslides and rock avalanches (MRSFs), which are often complex and multiphase (Bates & Jackson 1987;Braathen et al 2004;Evans et al 2006;Hermanns et al 2006;Jarman 2006;Cruden & Varnes 2009;Frattini et al 2012;Hermanns & Longva 2012;Luckman 2013;Shakesby 2014;Brideau & Roberts 2015). This definition is used here to distinguish RSF from 'rockfall'the smaller-scale process involving the piecemeal detachment and free fall of individual rock particleseven though the term rockfall is commonly used at all scales, including the largest landslides and rock avalanches (MRSFs), which are often complex and multiphase (Bates & Jackson 1987;Braathen et al 2004;Evans et al 2006;Hermanns et al 2006;Jarman 2006;Cruden & Varnes 2009;Frattini et al 2012;Hermanns & Longva 2012;Luckman 2013;Shakesby 2014;Brideau & Roberts 2015).…”

Section: Definitions and Criteria For Recognition Of Srsfsmentioning

confidence: 99%

“…The term 'rock-slope failure' (RSF) refers to both: (i) a mass-movement process involving the deformation and loss of integrity of a volume of intact bedrock followed by its en masse collapse and downslope movement under gravity; and (ii) the resulting landform. This definition is used here to distinguish RSF from 'rockfall'the smaller-scale process involving the piecemeal detachment and free fall of individual rock particleseven though the term rockfall is commonly used at all scales, including the largest landslides and rock avalanches (MRSFs), which are often complex and multiphase (Bates & Jackson 1987;Braathen et al 2004;Evans et al 2006;Hermanns et al 2006;Jarman 2006;Cruden & Varnes 2009;Frattini et al 2012;Hermanns & Longva 2012;Luckman 2013;Shakesby 2014;Brideau & Roberts 2015).…”

Section: Definitions and Criteria For Recognition Of Srsfsmentioning

confidence: 99%

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Small rock‐slope failures conditioned by Holocene permafrost degradation: a new approach and conceptual model based on Schmidt‐hammer exposure‐age dating, Jotunheimen, southern Norway

Matthews

Winkler

Wilson

et al. 2018

Boreas

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October): Small rock-slope failures conditioned by Holocene permafrost degradation: a new approach and conceptual model based on Schmidt-hammer exposure-age dating, Jotunheimen, southern Norway.Rock-slope failures (RSFs) constitute significant natural hazards, but the geophysical processes that control their timing are poorly understood. However, robust chronologies can provide valuable information on the environmental controls on RSFoccurrence: information that can inform models of RSF activity in response to climatic forcing. This study uses Schmidt-hammer exposure-age dating (SHD) of boulder deposits to construct a detailed regional Holocene chronology of the frequency and magnitude of small rock-slope failures (SRSFs) in Jotunheimen, Norway. By focusing on the depositional fans of SRSFs (≤10 3 m 3 ), rather than on the corresponding features of massive RSFs (~10 8 m 3 ), 92 singleevent RSFs are targeted for chronology building. A weighted SHD age-frequency distribution and probability density function analysis indicated four centennial-to millennial-scale periods of enhanced SRSF frequency, with a dominant mode at~4.5 ka. Using change detection and discreet Meyer wavelet analysis, in combination with existing permafrost depth models, we propose that enhanced SRSFactivity was primarily controlled by permafrost degradation. Long-term relative change in permafrost depth provides a compelling explanation for the high-magnitude departures from the SRSF background rate and accounts for: (i) the timing of peak SRSF frequency; (ii) the significant lag (~2.2 ka) between the Holocene Thermal Maximum and the SRSF frequency peak; and (iii) the marked decline in frequency in the late-Holocene. This interpretationis supported bygeomorphological evidence, as the spatialdistributionofSRSFs isstrongly correlatedwith the aspect-dependent lower altitudinal limit ofmountain permafrost in clifffaces. Resultsare indicative of a causal relationship between episodes of relatively warm climate, permafrost degradation and the transition to a seasonal-freezing climatic regime. This study highlights permafrost degradation as a conditioning factor for cliff collapse, and hence the importance of paraperiglacial processes; a result with implications for slope instability in glacial and periglacial environments under global warming scenarios.

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Section: Definitions and Criteria For Recognition Of Srsfsmentioning

confidence: 99%

Section: Definitions and Criteria For Recognition Of Srsfsmentioning

confidence: 99%

Small rock‐slope failures conditioned by Holocene permafrost degradation: a new approach and conceptual model based on Schmidt‐hammer exposure‐age dating, Jotunheimen, southern Norway

Matthews

Winkler

Wilson

et al. 2018

Boreas

View full text Add to dashboard Cite

show abstract

“…Petley et al, 2002Petley et al, , 2005Kilburn and Petley, 2003;Intrieri et al, 2018). In first-time brittle failures, creep reflects damage accumulation during the reduction of intact material strength, discontinuity strength, or both (Brideau and Roberts, 2015; and references therein) and consequent stress concentration (Cornelius and Scott, 1993). In such slopes, acceleration increases over time (Petley et al, 2002;Kilburn and Petley, 2003).…”

Section: Mechanisms Of Failure 15mentioning

confidence: 99%

“…Geomechanical behaviour of the Pampahasi slope indicates failure nearer to that of sediment than to rock. Both the La Paz 10 Formation and the Pampahasi gravel have compressive strengths well below 1 MPa, the threshold typically used to differentiate between rock and sediment (Brideau and Roberts, 2015). Parts of the main failure zone, as well as various minor rupture zones within the landslide body, likely follow weak, fine-grained seams sheared during the Pampahasi paleolandslide or other past failures.…”

Section: Controlling Factorsmentioning

confidence: 99%

Changes in ground deformation prior to and following a large urban landslide in La Paz, Bolivia revealed by advanced InSAR

Roberts¹,

Rabus²,

Clague³

et al. 2018

Preprint

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We characterize and compare creep preceding and following the 2011 Pampahasi landslide (~40 Mm 3 ± 50%) in the city of La Paz, Bolivia, using spaceborne RADAR interferometry (InSAR) that combines displacement records from both distributed and point scatterers. The failure remobilised deposits of an ancient landslide in weakly cemented, predominantly 15 fine-grained sediments and affected ~1.5 km 2 of suburban development. During the 30 months preceding failure, about half of the toe area was creeping at 3-8 cm/a and localized parts of the scarp area showed displacements of up to 14 cm/a. Changes in deformation in the 10 months following the landslide are contrary to the common assumption that stress released during a discrete failure increases stability. During that period, most of the landslide toe and areas near the headscarp accelerated, respectively, to 4-14 and 14 cm/a. The extent of deformation increased to cover most, or probably all, of the 20 2011 landslide as well as adjacent parts of the slope and plateau above. The InSAR-measured displacement patternssupplemented by field observations and by optical satellite images -indicate that kinematically complex, steady-state creep along pre-existing sliding surfaces temporarily accelerated in response to heavy rainfall, after which the slope quickly achieved a slightly faster and expanded steadily creeping state. This case study demonstrates that high-quality groundsurface motion fields derived using spaceborne InSAR can help to characterize creep mechanisms, quantify spatial and 25 temporal patterns of slope activity, and identify isolated small-scale instabilities. Characterizing slope instability before, during, and after the 2011 Pampahasi landslide is particularly important for understanding landslide hazard in La Paz, half of which is underlain by similar, large paleolandslides.Nat.

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“…Improvement of radar systems is increasing ground resolution and phase quality, and the establishment of satellite constellations is improving temporal resolution and interferometric coherence. Due to such improvements, pre-failure accelerated creep has recently been detected and measured, for both natural Handwerger et al, 2019) and cut (Carlà et al, 2018) slopes. Such advancements similarly improve opportunities to analyze post-failure creep.…”

Section: Introductionmentioning

confidence: 99%

Changes in ground deformation prior to and following a large urban landslide in La Paz, Bolivia, revealed by advanced InSAR

Roberts

Rabus

Clague

et al. 2019

Nat. Hazards Earth Syst. Sci.

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Abstract. We characterize and compare creep preceding and following the complex 2011 Pampahasi landslide (∼40 Mm3±50 %) in the city of La Paz, Bolivia, using spaceborne radar interferometry (InSAR) that combines displacement records from both distributed and point scatterers. The failure remobilized deposits of an ancient complex landslide in weakly cemented, predominantly fine-grained sediments and affected ∼1.5 km2 of suburban development. During the 30 months preceding failure, about half of the toe area was creeping at 3–8 cm a−1 and localized parts of the scarp area showed displacements of up to 14 cm a−1. Changes in deformation in the 10 months following the landslide demonstrate an increase in slope activity and indicate that stress redistribution resulting from the discrete failure decreased stability of parts of the slope. During that period, most of the landslide toe and areas near the head scarp accelerated, respectively, to 4–14 and 14 cm a−1. The extent of deformation increased to cover most, or probably all, of the 2011 landslide as well as adjacent parts of the slope and plateau above. The InSAR-measured displacement patterns, supplemented by field observations and optical satellite images, reveal complex slope activity; kinematically complex, steady-state creep along pre-existing sliding surfaces accelerated in response to heavy rainfall, after which slightly faster and expanded steady creeping was re-established. This case study demonstrates that high-quality ground-surface motion fields derived using spaceborne InSAR can help to characterize creep mechanisms, quantify spatial and temporal patterns of slope activity, and identify isolated small-scale instabilities; such details are especially useful where knowledge of landslide extent and activity is limited. Characterizing slope activity before, during, and after the 2011 Pampahasi landslide is particularly important for understanding landslide hazard in La Paz, half of which is underlain by similar large paleolandslides.

show abstract

Mass Movement in Bedrock

Cited by 7 publications

References 253 publications

Small rock‐slope failures conditioned by Holocene permafrost degradation: a new approach and conceptual model based on Schmidt‐hammer exposure‐age dating, Jotunheimen, southern Norway

Small rock‐slope failures conditioned by Holocene permafrost degradation: a new approach and conceptual model based on Schmidt‐hammer exposure‐age dating, Jotunheimen, southern Norway

Changes in ground deformation prior to and following a large urban landslide in La Paz, Bolivia revealed by advanced InSAR

Changes in ground deformation prior to and following a large urban landslide in La Paz, Bolivia, revealed by advanced InSAR

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