In hilly and mountainous urbanized areas, shallow and rapid landslides cause significant, often unpredictable, hazard conditions. The mass movements may cross roads, crash or bury vehicle, destroy infrastructures, run into villages and houses and kill people. However, in such critical context the landslide source areas are often found along the road network. This represents one of the most recurring situations during not particularly exceptional rainstorms in Northern Tuscany. Owing to its geographical, geomorphologic and climatic features, the Northern Tuscany (Northern Tuscan Apennines, Apuan Alps, Garfagnana, Serchio Valley, Versilia) is frequently hit by rainstorms. In many cases such meteorological events trigger rapid and shallow landslides. They are generally first time movements, mainly referable to complex, translational debris slide-flow or soil slip-debris flows, typically triggered by intense rainfall. In the study area they occurred in peculiar geologic and geomorphologic environments: colluvium/debris thin slope cover (from few decimetres to 1-2 metres thick), semi-permeable or impermeable bedrock, hollow shaped slope, high slope gradient. Despite their little size, they caused heavy damage and also deaths, due to their high speed and erosion power. Less intense rainfall often can trigger such mass movements along the road network, which probably are caused by the lack or absence of a correct maintenance of the road drainage systems. In fact, the concentration and of uncontrolled running water on the roads and its subsequent flowing downslope may produce an “unnatural” increase in pore pressure that the only rainfall, hitting the same slope in natural conditions, should not have produced. Actually, this phenomenon generates the reaching and exceeding of the local critical rainfall threshold, making landslide prevision and landslide hazard assessment difficult. This paper summarises characteristics and main effects of the meteorological events, which hit the Northern Tuscany in December 2009 and October 2010, focusing on the landslides triggered and on their geological, geomorphologic and geotechnical features.

Fragility of territory and infrastructures resulting from not heavy meteorological events: case studies in Northern Tuscany, Italy

D'AMATO AVANZI, GIACOMO ALFREDO;GALANTI, YURI;GIANNECCHINI, ROBERTO;PUCCINELLI, ALBERTO
2011-01-01

Abstract

In hilly and mountainous urbanized areas, shallow and rapid landslides cause significant, often unpredictable, hazard conditions. The mass movements may cross roads, crash or bury vehicle, destroy infrastructures, run into villages and houses and kill people. However, in such critical context the landslide source areas are often found along the road network. This represents one of the most recurring situations during not particularly exceptional rainstorms in Northern Tuscany. Owing to its geographical, geomorphologic and climatic features, the Northern Tuscany (Northern Tuscan Apennines, Apuan Alps, Garfagnana, Serchio Valley, Versilia) is frequently hit by rainstorms. In many cases such meteorological events trigger rapid and shallow landslides. They are generally first time movements, mainly referable to complex, translational debris slide-flow or soil slip-debris flows, typically triggered by intense rainfall. In the study area they occurred in peculiar geologic and geomorphologic environments: colluvium/debris thin slope cover (from few decimetres to 1-2 metres thick), semi-permeable or impermeable bedrock, hollow shaped slope, high slope gradient. Despite their little size, they caused heavy damage and also deaths, due to their high speed and erosion power. Less intense rainfall often can trigger such mass movements along the road network, which probably are caused by the lack or absence of a correct maintenance of the road drainage systems. In fact, the concentration and of uncontrolled running water on the roads and its subsequent flowing downslope may produce an “unnatural” increase in pore pressure that the only rainfall, hitting the same slope in natural conditions, should not have produced. Actually, this phenomenon generates the reaching and exceeding of the local critical rainfall threshold, making landslide prevision and landslide hazard assessment difficult. This paper summarises characteristics and main effects of the meteorological events, which hit the Northern Tuscany in December 2009 and October 2010, focusing on the landslides triggered and on their geological, geomorphologic and geotechnical features.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/246204
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