Mathematical modeling of talus development

Obanawa, Hiroyuki; Matsukura, Yukinori

doi:10.1016/j.cageo.2006.05.004

Cited by 19 publications

(16 citation statements)

References 11 publications

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“…The rate of talus aggradation thus decays exponentially ( Fig. 2c) (Hutchinson 1998;Obanawa and Matsukura 2006). During talus accumulation, the slope of its surface steepens from initially low-dipping to steep-dipping, until a stable dip value of a 'mature' talus slope is attained ( Fig.…”

Section: Geological Settingmentioning

confidence: 94%

“…Over glacial-interglacial cycles the 'talus window' (Hales and Roering 2005) varies considerably in altitude. Field observations (Penck 1924), degradation of man-made cliffs (Hutchinson 1998), and mathematical analyses (Bakker and Le Heux 1952;Caine 1969;Obanawa and Matsukura 2006) indicate that the onlap surface of an aggrading talus slope develops in a convex shape while the cliff retreats in its original steepness and declines in vertical height (Fig. 2b).…”

Section: Geological Settingmentioning

confidence: 99%

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Quaternary carbonate-rocky talus slope successions (Eastern Alps, Austria): sedimentary facies and facies architecture

Sanders

Ostermann

Kramers

2009

Facies

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Quaternary carbonate-lithic talus slope successions of the Eastern Alps record an overall correlation between prevalent sedimentary facies, depositional geometry, and geomorphic maturity of the slope. After exposure of high cliffs by deglaciation or rocksliding, a low-dipping immature talus dominated by unsorted rockfalls initially accumulates. With progressive talus buildup, slope segments of different dips develop. Concomitantly, prevalent depositional processes change to grain flows and sorted rockfalls in the proximal, steep-dipping (35°-30°) slope segment, while deposits of cohesive debris-flows, ephemeral fluid flows and larger rockfalls prevail in the distal, lower-dipping slope segment. In mature talus deposystems, the proximal slope succession overlies the lower-dipping package of the distal slope along a thin 'downlap interval'. Immediately after cliff exposure by deglaciation or rocksliding, talus may aggrade at rates of up to a few tens of meters per 1,000 years, but the accumulation rate slows strongly with progressive maturity of slopes.

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Section: Geological Settingmentioning

confidence: 94%

Section: Geological Settingmentioning

confidence: 99%

Quaternary carbonate-rocky talus slope successions (Eastern Alps, Austria): sedimentary facies and facies architecture

Sanders

Ostermann

Kramers

2009

Facies

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“…The rates of topographic change due to these two modes of retreat are called the "rate of declining retreat" and "rate of parallel retreat". Obanawa and Matsukura (2006) have proposed a mathematical model for the topographic change of a cross section of a talus landform, based on the material balance between the volumes of erosion and deposition. The model is based on equations relating to topographic forms and the rates of topographic change.…”

Section: Definition Of Geomorphological Termsmentioning

confidence: 99%

“…These two equations are shown in Appendix A (for detailed derivation of the equations, see Obanawa and Matsukura, 2006). Numerical integration by the finite difference method, using a computer, is used to find solutions of these equations.…”

Section: Equations In the Modelmentioning

confidence: 99%

“…They are unable to separate the rate of retreat of a cliff into two components corresponding to the rates of parallel retreat and declining retreat, so that they cannot describe topographic change involving both types of retreat. To overcome this problem, Obanawa and Matsukura (2006) proposed a new mathematical model for talus development and retreat of a cliff behind the talus, which can deal with the rates of declining cliff retreat and parallel retreat independently. This allows better modeling of changes in talus topography.…”

Section: Introductionmentioning

confidence: 99%

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Cliff retreat and talus development at the caldera wall of Mount St. Helens: Computer simulation using a mathematical model

Obanawa

Matsukura

2008

Geomorphology

Self Cite

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To simulate the landform evolution at the caldera wall of Mount St. Helens, USA, a mathematical model for talus development was applied to model the topographic change during the 11years from the volcanic eruption, i.e., from formation of the cliff. Simulated results show that the topographic change is predicted to be large for about 10years after the eruption and to decline thereafter. If snow accumulation in the talus slope deposits is negligible, the talus top will not reach the cliff top within 300years after the eruption. Talus growth in Mount St. Helens was much faster than that in the Chichibu Basin, Japan. This may indicate the low strength and/or high weathering rate of the rockwall of Mount St. Helens, resulting in rapid production of debris and rapid retreat of the cliff.

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Environmental drivers of paraglacial time duration and intensity for scree slopes dynamics in forested environments

Germain

Stabile‐Caillé

2023

Earth Surf Processes Landf

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The highly fissile lithology of the rockwalls and the diversity of mass-wasting processes provide a specific character to the active talus slopes of the northern Gaspé Peninsula since deglaciation. At a regional scale, the geology of the rockwalls, the patterns and modalities of deglaciation and the evolution towards a cold temperate morphoclimatic regime in a maritime context still influence the geomorphological dynamics of scree slopes today. At a local scale, the south-north orientation of the main coastal valleys influences insolation and exposure to prevailing winds, which in turn influence the snow cover regime and the occurrence of freeze-thaw cycles. The statistical analyses carried out from the mapping of 43 talus slopes and their geometric variables allowed the identification of significant environmental factors for the characterization of the dominant geomorphic processes: snow avalanches, frostcoasted clast flows, debris flows and rockfalls. Slope aspect appears to be a key parameter in the nature of the processes acting on the talus slopes. East-and northfacing talus slopes are generally covered by a significant snowpack in winter and the dominant processes are snow avalanches and debris flows. West-and south-facing talus slopes face prevailing winds and insolation and are subject to frost-coated clast flows, the main driver for forest regression, and rockfalls. However, the evolution of scree slopes in forested environments remains extremely complex due to the multiscale components that affect their evolution in the short, medium and long term.

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Mathematical modeling of talus development

Cited by 19 publications

References 11 publications

Quaternary carbonate-rocky talus slope successions (Eastern Alps, Austria): sedimentary facies and facies architecture

Quaternary carbonate-rocky talus slope successions (Eastern Alps, Austria): sedimentary facies and facies architecture

Cliff retreat and talus development at the caldera wall of Mount St. Helens: Computer simulation using a mathematical model

Environmental drivers of paraglacial time duration and intensity for scree slopes dynamics in forested environments

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