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| Titel |
The application of numerical debris flow modelling for the generation of physical vulnerability curves |
| VerfasserIn |
B. Quan Luna, J. Blahut, C. J. Westen, S. Sterlacchini, T. W. J. Asch, S. O. Akbas |
| 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 ; 11, no. 7 ; Nr. 11, no. 7 (2011-07-25), S.2047-2060 |
| Datensatznummer |
250009573
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| Publikation (Nr.) |
 copernicus.org/nhess-11-2047-2011.pdf |
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| Zusammenfassung |
| For a quantitative assessment of debris flow risk, it is essential to
consider not only the hazardous process itself but also to perform an
analysis of its consequences. This should include the estimation of the
expected monetary losses as the product of the hazard with a given magnitude
and the vulnerability of the elements exposed. A quantifiable integrated
approach of both hazard and vulnerability is becoming a required practice in
risk reduction management. This study aims at developing physical
vulnerability curves for debris flows through the use of a dynamic run-out
model. Dynamic run-out models for debris flows are able to calculate
physical outputs (extension, depths, velocities, impact pressures) and to
determine the zones where the elements at risk could suffer an impact. These
results can then be applied to consequence analyses and risk calculations.
On 13 July 2008, after more than two days of intense rainfall,
several debris and mud flows were released in the central part of the
Valtellina Valley (Lombardy Region, Northern Italy). One of the largest
debris flows events occurred in a village called Selvetta. The debris flow
event was reconstructed after extensive field work and interviews with local
inhabitants and civil protection teams. The Selvetta event was modelled with
the FLO-2D program, an Eulerian formulation with a finite differences
numerical scheme that requires the specification of an input hydrograph. The
internal stresses are isotropic and the basal shear stresses are calculated
using a quadratic model. The behaviour and run-out of the flow was
reconstructed. The significance of calculated values of the flow depth,
velocity, and pressure were investigated in terms of the resulting damage to
the affected buildings. The physical damage was quantified for each affected
structure within the context of physical vulnerability, which was calculated
as the ratio between the monetary loss and the reconstruction value. Three
different empirical vulnerability curves were obtained, which are functions
of debris flow depth, impact pressure, and kinematic viscosity, respectively.
A quantitative approach to estimate the vulnerability of an exposed element
to a debris flow which can be independent of the temporal occurrence of the
hazard event is presented. |
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