Hillslope Evolution by Bedrock Landslides

Densmore, Alexander L.; Anderson, Robert S.; McAdoo, Brian G.; Ellis, Michael A.

doi:10.1126/science.275.5298.369

Cited by 119 publications

(106 citation statements)

References 20 publications

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“…Canyon incision and wall undercutting are therefore proposed as the first order driver of landslides in the CS canyons. The larger landslides occur where scouring of the canyon floor undermines and steepens the base of the canyon wall, whereas the upper, smaller slides occur due to loss of support; this is comparable to the origin of terrestrial bedrock landslides in the physical model of Densmore et al (1997). In spite of the numerous canyon wall failures, we notice a general absence of landslide deposits within the canyon axes.…”

Section: Causes Of Landslidesmentioning

confidence: 84%

Deep-Seated Bedrock Landslides and Submarine Canyon Evolution in an Active Tectonic Margin: Cook Strait, New Zealand

Micallef

Mountjoy

Canals

et al. 2011

Submarine Mass Movements and Their Consequences

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The Cook Strait sector of the Hikurangi subduction margin, off south-east central New Zealand, is dominated by a multi-branched canyon system where landslides are widespread. The objective of this study is to determine the character, origin, and influence of these landslides on the evolution of the canyon system. Multibeam bathymetry covering seven submarine canyons is utilised to characterise landslides' spatial distribution, morphological attributes and area-frequency characteristics. We demonstrate that mass movements within the Cook Strait canyons consist of spatially dense, predominantly retrogressive, small, deep-seated, translational bedrock landslides occurring in Late Cenozoic sequences. These landslides affect up to a quarter of the canyoned area. Concentration of landslides in the shallow canyon reaches (down to 800 m) is attributed to the influence of oceanographic processes originating on the continental shelf such as tidegenerated currents, dense shelf water cascading and internal waves. Canyon incision and wall undercutting, locally favoured by underlying lithological control, are proposed as major landslide drivers in Cook Strait. Ground motion during regional earthquakes is considered a secondary cause. Retrogressive landslides are responsible for canyon widening and wall retreat, cross-sectional asymmetry, preconditioning for additional failure, destabilisation of adjacent slopes and delivery of sediment into canyon floors.

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Section: Causes Of Landslidesmentioning

confidence: 84%

Deep-Seated Bedrock Landslides and Submarine Canyon Evolution in an Active Tectonic Margin: Cook Strait, New Zealand

Micallef

Mountjoy

Canals

et al. 2011

Submarine Mass Movements and Their Consequences

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“…However, the landslides do not propagate in this model like the avalanches in the sandpile model; instead an explicit rule for their size was introduced. Motivated by experiments (Densmore et al, 1997), it is assumed that the size of a landslide being initiated at a certain location depends on the time span since the previous landslide at the location. The model yields powerlaw distributions with realistic exponents for the landslide volumes, but clean power laws can be recognized only over about one order of magnitude in landslide volume, which is in fact a very narrow range.…”

Section: The Role Of Time-dependent Weakeningmentioning

confidence: 99%

Landslides, sandpiles, and self-organized criticality

Hergarten

2003

Nat. Hazards Earth Syst. Sci.

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Abstract. Power-law distributions of landslides and rockfalls observed under various conditions suggest a relationship of mass movements to self-organized criticality (SOC). The exponents of the distributions show a considerable variability, but neither a unique correlation to the geological or climatic situation nor to the triggering mechanism has been found. Comparing the observed size distributions with models of SOC may help to understand the origin of the variation in the exponent and finally help to distinguish the governing components in long-term landslide dynamics. However, the three most widespread SOC models either overestimate the number of large events drastically or cannot be consistently related to the physics of mass movements. Introducing the process of time-dependent weakening on a long time scale brings the results closer to the observed statistics, so that time-dependent weakening may play a major part in the long-term dynamics of mass movements.

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“…Schumm et al, 1987;Hasbargen and Paola, 2000;Lague et al, 2003;Hancock and Willgoose, 2001;Bonnet and Crave, 2006), hillslope dynamics (e.g. Densmore et al, 1997;Roering et al, 2001), physical weathering (e.g. Goudie et al, 2002) and other systems teach us a great deal about how geomorphic systems operate.…”

Section: Introductionmentioning

confidence: 99%

Natural experiments in landscape evolution

Tucker

2009

Earth Surf Processes Landf

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A natural experiment in landscape evolution is a case study of landform development in which only one element varies significantly, and for which the driving forces, initial conditions, and/or boundary conditions are well constrained. Natural experiments provide a means of testing landscape evolution theory on the large space and time scales to which that theory applies. Natural experiments can involve either steady or transient conditions. Cases with steady conditions allow one to test predictions about the relationships among topography, erosion rates, and various attributes related to climate and material properties. Transient cases are valuable for distinguishing between models whose predictions might be similar, and therefore indistinguishable, under steady conditions. Essential ingredients of a natural experiment include minimal variation in all but one factor, good constraints on timing and/or rates, well-characterized processes, and high quality topographic data. Other useful ingredients include information about intermediate topographic states (such as a former valley profile revealed by strath terraces), and knowledge of the time history of erosion rates. In order to deepen our understanding of the physics and chemistry of longterm landscape evolution, there is a pressing need to identify natural experiments and develop the necessary databases to take advantage of them.

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Hillslope Evolution by Bedrock Landslides

Cited by 119 publications

References 20 publications

Deep-Seated Bedrock Landslides and Submarine Canyon Evolution in an Active Tectonic Margin: Cook Strait, New Zealand

Deep-Seated Bedrock Landslides and Submarine Canyon Evolution in an Active Tectonic Margin: Cook Strait, New Zealand

Landslides, sandpiles, and self-organized criticality

Natural experiments in landscape evolution

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