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| Titel |
Analysing the relationship between rainfalls and landslides to define a mosaic of triggering thresholds for regional-scale warning systems |
| VerfasserIn |
S. Segoni, A. Rosi, G. Rossi, F. Catani, N. Casagli |
| 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 ; 14, no. 9 ; Nr. 14, no. 9 (2014-09-29), S.2637-2648 |
| Datensatznummer |
250118675
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| Publikation (Nr.) |
 copernicus.org/nhess-14-2637-2014.pdf |
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| Zusammenfassung |
We propose an original approach to develop rainfall thresholds to be used in
civil protection warning systems for the occurrence of landslides at
regional scale (i.e. tens of thousands of kilometres), and we apply it to
Tuscany, Italy (23 000 km2).
Purpose-developed software is used to define statistical
intensity–duration rainfall thresholds by means of an automated and
standardized analysis of rainfall data. The automation and standardization
of the analysis brings several advantages that in turn have a positive
impact on the applicability of the thresholds to operational warning
systems. Moreover, the possibility of defining a threshold in very short
times compared to traditional analyses allowed us to subdivide the study area
into several alert zones to be analysed independently, with the aim of setting
up a specific threshold for each of them. As a consequence, a mosaic of
several local rainfall thresholds is set up in place of a single regional
threshold. Even if pertaining to the same region, the local thresholds vary
substantially and can have very different equations. We subsequently
analysed how the physical features of the test area influence the parameters
and the equations of the local thresholds, and found that some threshold
parameters can be put in relation with the prevailing lithology. In
addition, we investigated the possible relations between effectiveness of
the threshold and number of landslides used for the calibration.
A validation procedure and a quantitative comparison with some literature
thresholds showed that the performance of a threshold can be increased if
the areal extent of its test area is reduced, as long as a statistically
significant landslide sample is present. In particular, we demonstrated that
the effectiveness of a warning system can be significantly enhanced if a
mosaic of site-specific thresholds is used instead of a single regional
threshold. |
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