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| Titel |
Predicting storm-triggered debris flow events: application to the 2009 Ionian Peloritan disaster (Sicily, Italy) |
| VerfasserIn |
M. Cama, L. Lombardo, C. Conoscenti, V. Agnesi, E. Rotigliano |
| 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. 8 ; Nr. 15, no. 8 (2015-08-13), S.1785-1806 |
| Datensatznummer |
250119635
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| Publikation (Nr.) |
 copernicus.org/nhess-15-1785-2015.pdf |
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| Zusammenfassung |
The main assumption on which landslide susceptibility assessment by means of
stochastic modelling lies is that the past is the key to the future. As a
consequence, a stochastic model able to classify past known landslide events
should be able to predict a future unknown scenario as well. However,
storm-triggered multiple debris flow events in the Mediterranean region could
pose some limits on the operative validity of such an expectation, as they
are typically resultant of a randomness in time recurrence and magnitude and a
great spatial variability, even at the scale of small catchments. This is the
case for the 2007 and 2009 storm events, which recently hit
north-eastern Sicily with different intensities, resulting in largely
different disaster scenarios.
The study area is the small catchment of the Itala torrent (10 km2),
which drains from the southern Peloritani Mountains eastward to the Ionian
Sea, in the territory of the Messina province (Sicily, Italy). Landslides
have been mapped by integrating remote and field surveys, producing two
event inventories which include 73 debris flows, activated in 2007, and 616
debris flows, triggered by the 2009 storm. Logistic regression was applied
in order to obtain susceptibility models which utilize a set of predictors
derived from a 2 m cell digital elevation model and a 1 : 50 000 scale geologic
map. The research topic was explored by performing two types of
validation procedures: self-validation, based on the random partition of
each event inventory, and chrono-validation, based on the time partition of
the landslide inventory. It was therefore possible to analyse and compare
the performances both of the 2007 calibrated model in predicting the 2009
debris flows (forward chrono-validation), and vice versa of the
2009 calibrated model in predicting the 2007 debris flows (backward
chrono-validation).
Both of the two predictions resulted in largely acceptable performances in
terms of fitting, skill and reliability. However, a loss of performance and
differences in the selected predictors arose between the self-validated and the
chrono-validated models. These are interpreted as effects of the
non-linearity in the domain of the trigger intensity of the relationships
between predictors and slope response, as well as in terms of the different
spatial paths of the two triggering storms at the catchment scale. |
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