The landslide Inventory of the alpine areas of Regione Lombardia (12500 km2, northern Italy) is a large database with more than 60000 phenomena, among which 13863 slides, 802 complex landslides, 1000 large rock-falls, 276 earth-flows, 43600 debris flows and 354 rivers with considerable bedload. The inventory was produced through air photo interpretation (3 series of air-photos -1954, 1982, 1987- 1:20000-1:55000 scale) field checks and the use of historical records. Mapping consistency and quality have been guaranteed through systematic cross-checking of photo interpreters and an evaluation of mapping reliability. We present different applications of the Inventory, aimed to provide a support tool for landslide hazard assessment. We have studied the relationships between landslides and several environmental factors. Notwithstanding the complexity of the system, the relation between landslide and lithology has been clearly outlined, especially for deep seated landslides. Shallow landslides show a stronger dependence on slope morphology and, both directly and indirectly, on land use and vegetation. The influence of rainfall on landslides has not been clearly outlined, due to the impossibility to describe the local pattern of rainstorm at the regional scale of the analysis. We have analysed the frequency area statistics of landslides of Regione Lombardia The size distribution exhibit power-law scaling over a range of 5 order of magnitude, witnessing the completeness of the inventory. We have performed the analysis for different types of movement and different geological and geomorphological settings. The non-cumulative frequency-area distribution of landslides with areas larger than 0.04 km2 correlates well with a power law relation that corresponds to the ones reported in literature. For landslides with area smaller than 0.05 km2, the power law shows a lower exponent, witnessing a progressive undersampling of small landslides. We discuss in the paper reasons and criticisms related with these results. We have also preliminarily assessed the vulnerability of the region to landslides. More than 23 km2 of urbanized areas in the Lombardy Alps are located on landslides, and other 6 km2 lie on alluvial fans recognized as active and hazardous Moreover, several dams are located in proximity to landslides.
L’inventario delle frane e dei dissesti della Regione Lombardia è un’ampia base di dati comprendente oltre 60.000 fenomeni mappati, tra cui 13863 scorrimenti, 802 frane complesse, 1000 frane di crollo, 276 colate, 43600 debris flows and 354 torrenti con elevato trasporto solido. L’inventario è stato realizzato tramite foto-interpretazione multi-temporale (foto aeree del 1954, 1982, 1987, a scala 1:20000-1:55000), verifiche di terreno e integrazione con dati storici. Questa base dati può essere utilizzata per diversi scopi di programmazione e governo del territorio. Nel presente lavoro sono inoltre mostrate alcune applicazioni di questa base dati ai fini di una valutazione preliminare della pericolosità. Attraverso analisi di tipo statistico, sono state evidenziate ed analizzate le complesse relazioni tra i dissesti ed i diversi fattori geologico-ambientali s.l.. Sono state quindi analizzate le curve di frequenza delle aree in frana, al fine di valutare la completezza dell’inventario e di analizzare le distribuzioni di frequenza per diverse tipologie di dissesto e diverse condizioni ambientali. Si è infine stimata in modo preliminare la vulnerabilità del territorio alle frane, attraverso una semplice operazione di analisi spaziale dei dissesti rispetto agli elementi a rischio, attraverso tecniche GIS
Frattini, P., Crosta, G., Ceriani, M., Fossati, D. (2003). Inventario delle frane e dei dissesti della Regione Lombardia: analisi statistica e probabilistica per una valutazione preliminare della Pericolosità. In Atti I Convegno Nazionale AIGA (pp.427-448). Chieti : Rendina Editore.
Inventario delle frane e dei dissesti della Regione Lombardia: analisi statistica e probabilistica per una valutazione preliminare della Pericolosità
FRATTINI, PAOLO;CROSTA, GIOVANNI;
2003
Abstract
The landslide Inventory of the alpine areas of Regione Lombardia (12500 km2, northern Italy) is a large database with more than 60000 phenomena, among which 13863 slides, 802 complex landslides, 1000 large rock-falls, 276 earth-flows, 43600 debris flows and 354 rivers with considerable bedload. The inventory was produced through air photo interpretation (3 series of air-photos -1954, 1982, 1987- 1:20000-1:55000 scale) field checks and the use of historical records. Mapping consistency and quality have been guaranteed through systematic cross-checking of photo interpreters and an evaluation of mapping reliability. We present different applications of the Inventory, aimed to provide a support tool for landslide hazard assessment. We have studied the relationships between landslides and several environmental factors. Notwithstanding the complexity of the system, the relation between landslide and lithology has been clearly outlined, especially for deep seated landslides. Shallow landslides show a stronger dependence on slope morphology and, both directly and indirectly, on land use and vegetation. The influence of rainfall on landslides has not been clearly outlined, due to the impossibility to describe the local pattern of rainstorm at the regional scale of the analysis. We have analysed the frequency area statistics of landslides of Regione Lombardia The size distribution exhibit power-law scaling over a range of 5 order of magnitude, witnessing the completeness of the inventory. We have performed the analysis for different types of movement and different geological and geomorphological settings. The non-cumulative frequency-area distribution of landslides with areas larger than 0.04 km2 correlates well with a power law relation that corresponds to the ones reported in literature. For landslides with area smaller than 0.05 km2, the power law shows a lower exponent, witnessing a progressive undersampling of small landslides. We discuss in the paper reasons and criticisms related with these results. We have also preliminarily assessed the vulnerability of the region to landslides. More than 23 km2 of urbanized areas in the Lombardy Alps are located on landslides, and other 6 km2 lie on alluvial fans recognized as active and hazardous Moreover, several dams are located in proximity to landslides.
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