Alluvial fans form a wide category of morphological features built-up by a variety of flow and depositional processes. Despite the tendency of alluvial fans to be characterised by intense and extensive flooding, they have been historically preferred sites for urban development especially in alpine and pre-alpine areas. Hazard assessment on alluvial fans has consequently been an important research subject for many years. Researchers tried to characterise alluvial fan hazard by means of morphological parameters. This approach is used and discussed in this paper, starting from a series of data and observations collected in the Central Italian Alps (Lombardy Region). Statistical techniques have been used to verify the parameters able to discriminate alluvial fans in classes of different depositional processes. A sample population of 106 alluvial fans has been classified according to the determined discriminant function. Finally, historical data and the more discriminating morphometric parameters have been used to develop semi-empirical formulae to forecast maximum expected magnitude of flooding events characterised by different flow and depositional mechanisms. The results are discussed by comparison with those obtainable from similar approaches proposed in the literature.

Le conoidi detritico-alluvionali sono forme del territorio derivanti da vari e complessi processi di tipo deposizionale e caratterizzate da diverse tipologie di flusso. Nonostante siano interessate da frequenti ed intensi fenomeni di esondazione, le conoidi sono siti storicamente preferenziali di insediamento per le comunità delle aree alpine e prealpine, da cui l’importanza di valutare attentamente la loro pericolosità idrogeologica a fini di pianificazione territoriale e di protezione civile. Nel presente lavoro si discute l’utilizzo di parametri morfometrici per la caratterizzazione della pericolosità su conoide a partire da una serie di dati raccolti nelle Alpi Centrali (Lombardia, Italia). In primo luogo sono stati analizzati statisticamente i parametri morfometrici e geologici, al fine di individuare quelli più adatti a descrivere e caratterizzare le diverse tipologie di trasporto e deposizione e l’intensità attesa degli eventi alluvionali in conoide. Un campione di 106 conoidi alpine è stato quindi classificato attraverso l’analisi discriminante in base alle diverse tipologie attese di trasporto e deposizione. Infine, sono state sviluppate formule semi-empiriche per il calcolo dell’intensità massima attesa degli eventi alluvionali in conoide, sulla base dei dati storici e dei parametri morfometrici e geologici raccolti.

Frattini, P., Ceriani, M., Crosta, G. (2002). A statistical approach for hazard assessment on alluvial fans. QUADERNI DI GEOLOGIA APPLICATA- SERIE A.I.G.A, 1, 1-20.

A statistical approach for hazard assessment on alluvial fans

FRATTINI, PAOLO;CROSTA, GIOVANNI
2002

Abstract

Alluvial fans form a wide category of morphological features built-up by a variety of flow and depositional processes. Despite the tendency of alluvial fans to be characterised by intense and extensive flooding, they have been historically preferred sites for urban development especially in alpine and pre-alpine areas. Hazard assessment on alluvial fans has consequently been an important research subject for many years. Researchers tried to characterise alluvial fan hazard by means of morphological parameters. This approach is used and discussed in this paper, starting from a series of data and observations collected in the Central Italian Alps (Lombardy Region). Statistical techniques have been used to verify the parameters able to discriminate alluvial fans in classes of different depositional processes. A sample population of 106 alluvial fans has been classified according to the determined discriminant function. Finally, historical data and the more discriminating morphometric parameters have been used to develop semi-empirical formulae to forecast maximum expected magnitude of flooding events characterised by different flow and depositional mechanisms. The results are discussed by comparison with those obtainable from similar approaches proposed in the literature.
Articolo in rivista - Articolo scientifico
Alluvial fans, geologic hazards, multivariate statistical analysis, debris flows, event magnitude, Lombardy, Italy
English
2002
1
1
20
none
Frattini, P., Ceriani, M., Crosta, G. (2002). A statistical approach for hazard assessment on alluvial fans. QUADERNI DI GEOLOGIA APPLICATA- SERIE A.I.G.A, 1, 1-20.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/39004
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