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| Titel |
Large scale debris-flow hazard assessment: a geotechnical approach and GIS modelling |
| VerfasserIn |
G. Delmonaco, G. Leoni, C. Margottini, C. Puglisi, D. Spizzichino |
| 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 ; 3, no. 5 ; Nr. 3, no. 5, S.443-455 |
| Datensatznummer |
250001241
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| Publikation (Nr.) |
 copernicus.org/nhess-3-443-2003.pdf |
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| Zusammenfassung |
| A deterministic distributed model has
been developed for large-scale debris-flow hazard analysis in the basin of
River Vezza (Tuscany Region – Italy). This area (51.6 km 2 ) was
affected by over 250 landslides. These were classified as debris/earth
flow mainly involving the metamorphic geological formations outcropping in
the area, triggered by the pluviometric event of 19 June 1996. In the last
decades landslide hazard and risk analysis have been favoured by the
development of GIS techniques permitting the generalisation, synthesis and
modelling of stability conditions on a large scale investigation (>1:10
000). In this work, the main results derived by the application of a
geotechnical model coupled with a hydrological model for the assessment of
debris flows hazard analysis, are reported. This analysis has been
developed starting by the following steps: landslide inventory map derived
by aerial photo interpretation, direct field survey, generation of a
database and digital maps, elaboration of a DTM and derived themes (i.e.
slope angle map), definition of a superficial soil thickness map,
geotechnical soil characterisation through implementation of a
backanalysis on test slopes, laboratory test analysis, inference of the
influence of precipitation, for distinct return times, on ponding time and
pore pressure generation, implementation of a slope stability model
(infinite slope model) and generalisation of the safety factor for
estimated rainfall events with different return times. Such an approach
has allowed the identification of potential source areas of debris flow
triggering. This is used to detected precipitation events with estimated
return time of 10, 50, 75 and 100 years. The model shows a dramatic
decrease of safety conditions for the simulation when is related to a 75
years return time rainfall event. It corresponds to an estimated cumulated
daily intensity of 280–330 mm. This value can be considered the
hydrological triggering threshold for the whole Vezza basin. |
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