Frequency of debris flows and their relation with precipitation : a case study in the Central Alps, Italy
Articolo
Data di Pubblicazione:
2008
Citazione:
Frequency of debris flows and their relation with precipitation : a case study in the Central Alps, Italy / M. Pelfini, M. Santilli. - In: GEOMORPHOLOGY. - ISSN 0169-555X. - 101:4(2008 Nov), pp. 721-730.
Abstract:
Debris flows are very important and widespread mass movements, and represent a remarkable
geomorphological hazard. This research deals with debris flows in an alpine environment, studied using
dendrogeomorphological dating techniques, outlining their relation with precipitation, and analysing
possible changes in their frequency and intensity over time. The study area is the upper Valle del Gallo
(Northern Italy), a typical high mountain environment dominated by mass wasting processes, where many
debris-flow fans occupy the valley bottom. Dendrogeomorphological research was conducted on twelve of
these fans and two channels located on slopes. Tree growth anomalies (abrasion scars, compression wood
and abrupt growth changes) were used as dating methods. Two hundred and thirty nine debris debris-flow
events between 1875 and 2003 were dated using 757 trees (Pinus montana Mill.). Analysis between dated
events and precipitation suggests that debris flows in the study area could be triggered by 20–30 mm of rain
concentrated in a few hours. The debris-flow frequency tends to increase gradually, but the highest value
seems to have occurred in the period 1974–1983. This trend agrees with the historical occurrence of flooding
events in Northern Italy as inferred by literature, and with similar studies conducted in the Swiss Alps. The
results of this research are intended as a contribution for understanding the response of geomorphological
processes to climatic changes.
Tipologia IRIS:
01 - Articolo su periodico
Elenco autori:
M. Pelfini, M. Santilli
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