Geomorphic effects caused by heavy rainfall in southern Calabria (Italy) on 30 October–1 November 2015

Abstract

A severe rainfall event occurred in southern Calabria between 29 October and 2 November 2015, causing two deaths and serious damage to transport infrastructure. Widespread slope erosion and thousands of shallow landslides were triggered on the slopes, combined with flooding and transport of debris along the streams. Rains recorded by the regional gauge network and the national radar monitoring system were analysed by means of Kriging techniques. Ground effects were surveyed in the field, and mapped using post-event air photos taken along the coastal sector. Shallow landslides, soil erosion (including sheet, rill, and gully erosion), flooding, lateral erosion, and debris deposition along streambeds, overflow on lateral slopes, and fan deposition at the mouths of the streams were mapped at 1:60,000 scale. Isohyets of the rainfall eventin terms of cumulative maxima over 24 hare also shown on the Main Map. In Annex A, a list of notices of processes and/or damage, arranged by municipalities, with coordinates, types of ground effect, and synthetic descriptions, is also provided.

Heavy Rainfall Triggering Shallow Landslides: A Susceptibility Assessment by a GIS-Approach in a Ligurian Apennine Catchment (Italy)

“…The geological and morphological settings of the catchment area represent the main predisposing factors for the triggering of rainfall-induced landslides: a significant relationship between lithology, slope aspect and steepness, and instability processes in the Entella River basin was observed, according to other examples in literature [13,77,82]. Lithological heterogeneous sequences and chaotic complexes with a very high susceptibility to the development of landslides account for 80% of damaging events.…”

“…Destructive slope mass-movements, due to very short but heavy or intense prolonged rainfall, kill people every year and cause countless socio-economic damage. In modern urban society, a large portion of the population is exposed to landslides risk, which is greatly increased by global climate change [6,7], human interventions and landscape modifications, i.e., urbanization, deforestation, land-changes and the abandonment of rural areas [8][9][10][11][12][13]. Rainfall-induced shallow landslides initiate mainly on steep and very steep slopes, and involve small thickness materials originating from the weathering of the bedrock, as well as from soil erosion and downslope transportation due to meteoric and running waters.…”

Examples of Application of GASAKe for Predicting the Occurrence of Rainfall-Induced Landslides in Southern Italy

“…For past activations, further investigations may allow to better define the history of landslide mobilizations in the considered areas; rainfall data recorded at the surface by the gauge network may profitably be combined with weather radar prospections (cf. e.g., [68,69]). Moreover, it would be desirable that regional geological and hydrographic services were strengthened to guarantee adequate activities of surveying and monitoring of the geo-hydrological events, by implementing and updating suitable data bases on triggered slope movements (including details such as location, type, type of involved materials, dates of activation, damage).…”

Inventory of geo-hydrological phenomena in Genova municipality (NW Italy)

“…Risk mitigation strategies include even the essential role played by the communication and dissemination to people exposed to the hazard (Silvestro et al, 2012;Merz et al, 2014;Rago et al, 2017): a dedicated map is an important tool of diffusion of the actual knowledge of geo-hydrological hazard in a critical situation as in Genova Municipality. Such a tool should be part of a wider activity of communication aimed to reduce the inappropriate behavior that people often have particularly during flood events and consequently exposing themselves to a high risk.…”