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Titel |
Site-specific to local-scale shallow landslides triggering zones assessment using TRIGRS |
VerfasserIn |
M. Bordoni, C. Meisina, R. Valentino, M. Bittelli, S. Chersich |
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 Sciences ; 15, no. 5 ; Nr. 15, no. 5 (2015-05-21), S.1025-1050 |
Datensatznummer |
250119477
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Publikation (Nr.) |
copernicus.org/nhess-15-1025-2015.pdf |
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Zusammenfassung |
Rainfall-induced shallow landslides are common phenomena in many parts of
the world, affecting cultivation and infrastructure and sometimes causing
human losses. Assessing the triggering zones of shallow landslides is
fundamental for land planning at different scales. This work defines a
reliable methodology to extend a slope stability analysis from the
site-specific to local scale by using a well-established physically based
model (TRIGRS-unsaturated). The model is initially applied to a sample slope
and then to the surrounding 13.4 km2 area in Oltrepò Pavese (northern
Italy). To obtain more reliable input data for the model, long-term
hydro-meteorological monitoring has been carried out at the sample slope,
which has been assumed to be representative of the study area. Field
measurements identified the triggering mechanism of shallow failures and
were used to verify the reliability of the model to obtain pore water
pressure trends consistent with those measured during the monitoring
activity. In this way, more reliable trends have been modelled for past
landslide events, such as the April 2009 event that was assumed as a
benchmark. The assessment of shallow landslide triggering zones obtained
using TRIGRS-unsaturated for the benchmark event appears good for both the
monitored slope and the whole study area, with better results when a
pedological instead of geological zoning is considered at the regional
scale. The sensitivity analyses of the influence of the soil input data show
that the mean values of the soil properties give the best results in terms
of the ratio between the true positive and false positive rates. The scheme
followed in this work allows us to obtain better results in the assessment
of shallow landslide triggering areas in terms of the reduction in the
overestimation of unstable zones with respect to other distributed models
applied in the past. |
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