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Landslide susceptibility map
Programma Operativo Nazionale Programma Operativo Nazionale “Ricerca Ricerca e Competitività 2007 Ricerca e Competitività 2007‐ e Competitività 2007‐ 2007‐2013 2013” Regioni Regioni Convergenza ASSE I –– Sostegno ai mutamenti strutturali ASSE I Obiettivo Operativo: Aree scientifico Obiettivo Operativo: Aree scientifico‐‐tecnologiche generatrici di processi di trasformazione del sistema produttivo e creatrici di nuovi settori p Azione: Interventi di sostegno della ricerca industriale GEOLOGY GEOLOGY, GEOMORPHOLOGY AND LANDSLIDE GEOMORPHOLOGY AND LANDSLIDE SUCEPTIBILITY ALONG A HIGHWAY SECTION IN NORTHERN CALABRIA (ITALY) IN NORTHERN CALABRIA (ITALY) Working group: Francesco Muto1, Massimo Conforti2, Salvatore Critelli1, Davide Fabbricatore1, Luciana Filomena1, Teresa Pelle1, Valeria Rago1, Gaetano Robustelli1, Fabio Scarciglia1, Vincenzo Tripodi1 1 DiBEST-Università 2 CNR–ISAFOM, della Calabria, Arcavacata di Rende (CS), Italy Rende (CS), Italy Geological and Hydraulic Safety along Motorways and Railways Università della Calabria, Arcavacata di Rende (CS), 25 – 26 November 2014 Aula Magna Cosenza Sud Aims Research project PON01-01503 “Integrated Systems for Hydrogeological Risk Monitoring, Early Warning and Mitigation Along the Main Lifelines” – Multidisciplinary approach Hydrogeological risk mitigation and early warning along 3 highway sections of southern Italy Assessment of landslide susceptibility along the A3 highway section between Cosenza Sud and Altilia in northern Calabria (~26 km) Altilia Geological and structural setting Carbonate rocks (Mesozoic) N S trending Savuto fault system N‐S trending fault system Metamorphic rocks (Palaeozoic) Clay Unit (Upper Miocene) North Palaeozoic metamorphic and plutonic basement rocks Mesozoic to Paleogene g ophiolitic, p , metasedimentary and sedimentary rocks Tansi et al. (2007) Miocene to Miocene to Quaternary sedimentary cover N‐S fault Geomorphological features Geological, lithological and structural control; Weathering and morphodynamic processes Fault scarps, high local relief and stream incision, lateral and vertical juxtaposition of terrains with different behaviour in respect to erosion and mass movements COSENZA sud Geological map ALTILIA ‐ GRIMALDI COSENZA sud Lithological map p ALTILIA ‐ GRIMALDI Geomorphological map COSENZA sud ALTILIA ‐ GRIMALDI Landslide inventory maps Legend Landslide scarp Active Dormant Inactive Landslide body Fall Slide Flow 1955 Complex Shallow landslide P Present‐day td Landslides Calcarenite Sand and sandstone Sand and sandstone Sandstone and conglomerate Phyllite Altilia Altilia Sand (and soils) Gneiss Iassa Mancarelli Calcarenite Sandstone Conglomerate Ogliara site Geological map Ogliara Schist and phyllite and phyllite Garcito Piano d’Infante site Highway Geological map Garcito Geological map Fiego Legend Sand (and soils) Road Scarp p edge g Fiego site Gabions Highway Bulkhead piles Soils Entisols Inceptisols Mollisols Alfisols Pedological discontinuities Fiego site F2 Perched Perched water table F3 0,80 15,0 0,60 10,0 0,40 50 5,0 0 20 0,20 0,0 0,00 WL% IP% 30 25 IP = WL - WP 20 15 10 5 0 PD A Tasca P PD Bw PD 2Bt1 PD 2Bt2 PD 2Bt3 20,0 PD A Tasca Bw PD B PD 2B Bt1 PD 2B Bt2 PD 2B Bt3 1,00 F3 Bw F3 2Bt1 F3 2Bt2 F3 2Btg3 25,0 F3 B Bw F3 2B Bt1 F3 2B Bt2 F3 2Bttg3 1,20 F2 2 A F2 B/A F2 2Bt1 F2 2Bt2 1,40 30,0 2 A F2 2 F2 B B/A F2 2B Bt1 F2 2B Bt2 1,60 35,0 F1 AB F1 Bg1 F1 Btg2 F1 Bg3 F1 Bg4 F1 CB Clay (%) Clay (%) F1 AB Bg1 F1 B F1 Bttg2 F1 B Bg3 F1 B Bg4 F1 CB 50 45 40 35 30 25 20 15 10 5 0 GPI A GPI AB GPI 2Bt1 GPI 2Bt2 PD A Tasca P PD Bw PD 2Bt1 PD 2Bt2 PD 2Bt3 F3 Bw F3 2Bt1 F3 2Bt2 F3 2Btg3 F2 2 A F2 B/A F2 2Bt1 F2 2Bt2 F1 AB F1 Bg1 F1 Btg2 F1 Bg3 F1 Bg4 F1 CB GPI A GPI AB GPI 2Bt1 GPI 2Bt2 40,0 GP PI A GPI AB Bt1 GPI 2B GPI 2B Bt2 PD A Tasca D Bw PD PD 2 2Bt1 PD 2 2Bt2 PD 2 2Bt3 F3 3 Bw F3 2 2Bt1 F3 2 2Bt2 F3 2B Btg3 F2 2 A F2 B/A 2Bt1 F2 2 F2 2 2Bt2 F1 1 AB F1 Bg1 Btg2 F1 B F1 Bg3 F1 Bg4 1 CB F1 GPI A GPI AB 2Bt1 GPI 2 GPI 2 2Bt2 Some physical and rheological data ‐3 3) (ρa) BD (g cm BD ( )( ) Landslide susceptibility map Predisp posing fac ctors UCUs IIntersection t ti off predisposing factors Training set Landslides Conditional Analysis Landslide susceptibility map (50%) Testing g set (50%) Validation of landslide susceptibility map Thematic layers subdivided into classes UCU = Unique Condition Unit Estimation E ti ti off the th probability b bilit to t obtain bt i a certain t i density d it off landslides l d lid per each h UCU, UCU i.e. the probability (%) that a landslide could occur in that specific area Landslide susceptibility map UCUs map construction 7030 UCUs Landslide susceptibility map Relationship between the UCUs map and the landslide map Landslide Training set Testing set Highway Landslide susceptibility map Distribution of susceptibility classes Validation of the susceptibility map Susceptibility class Low Moderate High Very high Highway Susceptibility class Area (%) ( ) Landslide testing set (%) set (%) Very high High Moderate Low 9 29 24 38 33 47 17 3 Correct classification: most of the landslides is included in the 2 highest susceptibility classes High probability (80%) that a landslide could occur in the red-orange areas (The validation set mimics future landslides) 80% Landslide spatial risk Independent of of magnitude and return period of landslides of landslides Susceptibility Low Moderate High Very high Highway Vulnerable objects (highway) are overlain on the susceptibility on the susceptibility map Spatial Risk Very high High Moderate Low km 2.9 7.5 82 8.2 9.3 % 10.4 26.8 29 4 29.4 33.4 Relatively low spatial risk because vulnerable highway tracks are not are not included in higher‐risk areas or potential landslides will not involve them (e.g., viaducts) Spatial risk class Low Moderate High Very High Conclusive remarks Prominent role of litho-structural (fault scarps, spatial arrangement of different lithologies) and geomorphological features (high local relief, steep slopes stream dissection) as predisposing factors of landslides and their slopes, types Morphological and physical discontinuities caused on geological terrains by weathering and pedogenetic processes (soil horizon differentiation, argillification, oxidation, development of pedogenic structure, clay illuviation) interfingered with geomorphic dynamics (truncation by erosion, burial by younger sediments, e.g., colluvial material, slope deposits, landslide debris) Corresponding p g changes g in p physical y and g geomechanical p properties p of rock types (e.g., particle size distribution, liquid and plastic limits, bulk density, organic carbon content, porosity) in depth, evidenced by laboratory analyses High reliability of the landslide susceptibility and spatial risk assessment along the pilot section of the A3 highway between Cosenza Sud and Altilia (N Calabria) using the UCUs (Unique Condition Units) method and the conditional analysis Thank you for your for your attention !
