Programma Operativo Nazionale Ricerca e Competitività 2007 2013 2013 Regioni Convergenza ASSE I Sostegno ai mutamenti strutturali Obiettivo Operativo: Aree scientifico tecnologiche tecnologiche generatrici di processi di trasformazione del sistema produttivo e creatrici di nuovi settori Azione: Interventi di sostegno della ricerca industriale GEOLOGY, GEOMORPHOLOGY AND LANDSLIDE SUCEPTIBILITY ALONG A HIGHWAY SECTION IN NORTHERN CALABRIA (ITALY) Working group: Francesco Muto 1, Massimo Conforti 2, Salvatore Critelli 1, Davide Fabbricatore 1, Luciana Filomena 1, Teresa Pelle 1, Valeria Rago 1, Gaetano Robustelli 1, Fabio Scarciglia 1, Vincenzo Tripodi 1 1 DiBEST-Università della Calabria, Arcavacata di Rende (CS), Italy 2 CNR ISAFOM, Rende (CS), Italy Geological and Hydraulic Safety along Motorways and Railways Università della Calabria, Arcavacata di Rende (CS), 25 26 November 2014 Aula Magna
Aims Cosenza Sud 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 Metamorphic rocks (Palaeozoic) Tansi et al. (2007) Clay Unit (Upper Miocene) Palaeozoic metamorphic and plutonic basement rocks Mesozoic to Paleogene ophiolitic, metasedimentary and sedimentary rocks Miocene to Quaternary sedimentary cover North 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 COSENZA sud Geological map Lithological map ALTILIA GRIMALDI ALTILIA GRIMALDI
Geomorphological map COSENZA sud ALTILIA GRIMALDI
Landslide inventory maps Legend Landslide scarp Active Dormant Inactive Landslide body Fall Slide Flow Complex 1955 Present day Shallow landslide
Calcarenite Landslides Sandstone and conglomerate Sand and sandstone Phyllite Altilia Altilia Sand (and soils) Gneiss Iassa Mancarelli
Calcarenite Sandstone Geological map Ogliara Conglomerate Ogliara site
Schistand phyllite Geological map Garcito Garcito Highway Piano d Infante site
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 water table F3
Some physical and rheological data 40,0 35,0 30,0 25,0 20,0 15,0 10,0 50 5,0 0,0 Clay (%) BD (g cm 3 3 ) (ρa) 1,60 1,40 1,20 1,00 0,80 0,60 0,40 020 0,20 0,00 GPI A GPI AB GPI 2Bt1 GPI 2Bt2 F1 AB F1 Bg1 F1 Btg2 F1 Bg3 F1 Bg4 F1 CB F2 2 A F2 B/A F2 2Bt1 F2 2Bt2 F3 Bw F3 2Bt1 F3 2Bt2 F3 2Btg3 PD A Tasca PD Bw PD 2Bt1 PD 2Bt2 PD 2Bt3 GPI A GPI AB GPI 2Bt1 GPI 2Bt2 F1 AB F1 Bg1 F1 Btg2 F1 Bg3 F1 Bg4 F1 CB F2 2 A F2 B/A F2 2Bt1 F2 2Bt2 F3 Bw F3 2Bt1 F3 2Bt2 F3 2Btg3 PD A Tasca PD Bw PD 2Bt1 PD 2Bt2 PD 2Bt3 WL% IP% 50 45 IP = WL - WP 40 35 30 25 20 30 25 20 15 10 5 0 GPI A GPI AB GPI 2Bt1 GPI 2Bt2 F1 AB F1 Bg1 F1 Btg2 F1 Bg3 F1 Bg4 F1 CB F2 2 A F2 B/A F2 2Bt1 F2 2Bt2 F3 Bw F3 2Bt1 F3 2Bt2 F3 2Btg3 PD A Tasca PD Bw PD 2Bt1 PD 2Bt2 PD 2Bt3 15 10 5 0 GPI A GPI AB GPI 2Bt1 GPI 2Bt2 F1 AB F1 Bg1 F1 Btg2 F1 Bg3 F1 Bg4 F1 CB F2 F2 F2 2 F2 2 2 A B/A 2Bt1 2Bt2 F3 Bw F3 2Bt1 F3 2Bt2 F3 2Btg3 PD A Tasca PD Bw PD 2Bt1 PD 2Bt2 PD 2Bt3
Landslide susceptibility map UCUs Conditional Analysis Predisp posing fac ctors Intersection ti of predisposing factors Landslides Training set (50%) Landslide susceptibility map Testing set (50%) Validation of landslide susceptibility map Thematic layers subdivided into classes UCU = Unique Condition Unit Eti ti fth b bilit t bt i t i d it f l d lid h UCU Estimation of the probability to obtain a certain density of landslides per each UCU, i.e. the probability (%) that a landslide could occur in that specific area
UCUs map construction Landslide susceptibility map 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 Susceptibility class Low Moderate High Very high Highway Validation of the susceptibility map Susceptibility Landslide Area (%) class testing set (%) Very high 9 33 High 29 47 80% Moderate 24 17 Low 38 3 Correct classification: most of the landslides is included in the 2 highest susceptibility classes High probability (80%) that a landslide could High probability (80%) that a landslide could occur in the red-orange areas (The validation set mimics future landslides)
Susceptibility Low Moderate High Very high Highway Landslide spatial risk Independent of magnitude and return period of landslides Vulnerable objects (highway) are overlain on the susceptibility map Spatial risk class Low Moderate High Very High Spatial Risk km % Very high 2.9 10.4 High 7.5 26.8 Moderate 8.2 29.4 Low 9.3 33.4 Relatively low spatial risk because vulnerable highway tracks are not included in higher risk areas or potential landslides will not involve them (e.g., viaducts)
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 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 changes in physical and geomechanical 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
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