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| Titel |
Application of a probabilistic model of rainfall-induced shallow landslides to complex hollows |
| VerfasserIn |
A. Talebi, R. Uijlenhoet, P. A. Troch |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1561-8633
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| Digitales Dokument |
URL |
| Erschienen |
In: Natural Hazards and Earth System Science ; 8, no. 4 ; Nr. 8, no. 4 (2008-07-23), S.733-744 |
| Datensatznummer |
250005645
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| Publikation (Nr.) |
 copernicus.org/nhess-8-733-2008.pdf |
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| Zusammenfassung |
| Recently, D'Odorico and Fagherazzi (2003) proposed "A probabilistic model of
rainfall-triggered shallow landslides in hollows" (Water Resour. Res.,
39, 2003). Their model describes the long-term evolution of colluvial
deposits through a probabilistic soil mass balance at a point. Further
building blocks of the model are: an infinite-slope stability analysis; a
steady-state kinematic wave model (KW) of hollow groundwater hydrology; and
a statistical model relating intensity, duration, and frequency of extreme
precipitation. Here we extend the work of D'Odorico and Fagherazzi (2003) by
incorporating a more realistic description of hollow hydrology (hillslope
storage Boussinesq model, HSB) such that this model can also be applied to
more gentle slopes and hollows with different plan shapes. We show that
results obtained using the KW and HSB models are significantly different as
in the KW model the diffusion term is ignored. We generalize our results by
examining the stability of several hollow types with different plan shapes
(different convergence degree). For each hollow type, the minimum value of
the landslide-triggering saturated depth corresponding to the triggering
precipitation (critical recharge rate) is computed for steep and gentle
hollows. Long term analysis of shallow landslides by the presented model
illustrates that all hollows show a quite different behavior from the
stability view point. In hollows with more convergence, landslide occurrence
is limited by the supply of deposits (supply limited regime) or rainfall
events (event limited regime) while hollows with low convergence degree are
unconditionally stable regardless of the soil thickness or rainfall
intensity. Overall, our results show that in addition to the effect of slope
angle, plan shape (convergence degree) also controls the subsurface flow and
this process affects the probability distribution of landslide occurrence in
different hollows. Finally, we conclude that incorporating a more realistic
description of hollow hydrology (instead of the KW model) in landslide
probability models is necessary, especially for hollows with high
convergence degree which are more susceptible to landsliding. |
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