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| Titel |
Rainfall thresholds for the possible occurrence of landslides in Italy |
| VerfasserIn |
M. T. Brunetti, S. Peruccacci, M. Rossi, S. Luciani, D. Valigi, F. Guzzetti |
| 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 ; 10, no. 3 ; Nr. 10, no. 3 (2010-03-11), S.447-458 |
| Datensatznummer |
250008002
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| Publikation (Nr.) |
 copernicus.org/nhess-10-447-2010.pdf |
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| Zusammenfassung |
| In Italy, rainfall is the primary trigger of landslides that frequently cause
fatalities and large economic damage. Using a variety of information sources,
we have compiled a catalogue listing 753 rainfall events that have resulted
in landslides in Italy. For each event in the catalogue, the exact or
approximate location of the landslide and the time or period of initiation of
the slope failure is known, together with information on the rainfall
duration D, and the rainfall mean intensity I, that have resulted in the
slope failure. The catalogue represents the single largest collection of
information on rainfall-induced landslides in Italy, and was exploited to
determine the minimum rainfall conditions necessary for landslide occurrence
in Italy, and in the Abruzzo Region, central Italy. For the purpose, new
national rainfall thresholds for Italy and new regional rainfall thresholds
for the Abruzzo Region were established, using two independent statistical
methods, including a Bayesian inference method and a new Frequentist
approach. The two methods proved complementary, with the Bayesian method more
suited to analyze small data sets, and the Frequentist method performing
better when applied to large data sets. The new regional thresholds for the
Abruzzo Region are lower than the new national thresholds for Italy, and
lower than the regional thresholds proposed in the literature for the
Piedmont and Lombardy Regions in northern Italy, and for the Campania Region
in southern Italy. This is important, because it shows that landslides in
Italy can be triggered by less severe rainfall conditions than previously
recognized. The Frequentist method experimented in this work allows for the
definition of multiple minimum rainfall thresholds, each based on a different
exceedance probability level. This makes the thresholds suited for the design
of probabilistic schemes for the prediction of rainfall-induced landslides. A
scheme based on four probabilistic thresholds is proposed. The four
thresholds separate five fields, each characterized by different rainfall
intensity-duration conditions, and corresponding different probability of
possible landslide occurrence. The scheme can be implemented in landslide
warning systems that operate on rainfall thresholds, and on precipitation
measurements or forecasts. |
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