Landslide databases in the Geological Surveys of Europe

Acceso electrónico sólo desde el IGMELandslides are one of the most widespread geohazards in Europe, producing significant social and economic impacts. Rapid population growth in urban areas throughout many countries in Europe and extreme climatic scenarios can considerably increase landslide risk in the near future. Variability exists between European countries in both the statutory treatment of landslide risk and the use of official assessment guidelines. This suggests that a European Landslides Directive that provides a common legal framework for dealing with landslides is necessary. With this long-term goal in mind, this work analyzes the landslide databases from the Geological Surveys of Europe focusing on their interoperability and completeness. The same landslide classification could be used for the 849,543 landslide records from the Geological Surveys, from which 36% are slides, 10% are falls, 20% are flows, 11% are complex slides, and 24% either remain unclassified or correspond to another typology. Most of them are mapped with the same symbol at a scale of 1:25,000 or greater, providing the necessary information to elaborate European-scale susceptibility maps for each landslide type. A landslide density map was produced for the available records from the Geological Surveys (LANDEN map) showing, for the first time, 210,544 km2 landslide-prone areas and 23,681 administrative areas where the Geological Surveys from Europe have recorded landslides. The comparison of this map with the European landslide susceptibility map (ELSUS 1000 v1) is successful for most of the territory (69.7%) showing certain variability between countries. This comparison also permitted the identification of 0.98 Mkm2 (28.9%) of landslide-susceptible areas without records from the Geological Surveys, which have been used to evaluate the landslide database completeness. The estimated completeness of the landslide databases (LDBs) from the Geological Surveys is 17%, varying between 1 and 55%. This variability is due to the different landslide strategies adopted by each country. In some of them, landslide mapping is systematic; others only record damaging landslides, whereas in others, landslide maps are only available for certain regions or local areas. Moreover, in most of the countries, LDBs from the Geological Surveys co-exist with others owned by a variety of public institutions producing LDBs at variable scales and formats. Hence, a greater coordination effort should be made by all the institutions working in landslide mapping to increase data integration and harmonization.Earth Observation and Geohazards Expert Group (EOEG), EuroGeoSurveys, the Geological Surveys of Europe, BélgicaGeohazards InSAR Laboratory and Modeling Group, Instituto Geológico y Minero de España, EspañaRisk and Prevention Division, Bureau de Recherches Géologiques et Minières, FranciaEngineering Geology Department, Institute of Geology and Mineral Exploration, GreciaGeoHazard team, Geological Institute of Romania, RumaníaGeological Survey of Slovenia, EsloveniaCroatian Geological Survey, CroaciaItalian Institute for Environmental Protection and Research, Geological Survey of Italy, ItaliaSwiss Federal Office for the Environment, SuizaGeological Survey of Austria, AustriaPolish Geological Institute, National Research Institute, PoloniaGeological Survey of Ireland, IrlandaCzech Geological Survey, República ChecaFederal Institute for Geosciences and Natural Resources, AlemaniaGeological Survey of Norway, NoruegaCyprus Geological Survey, ChipreGeological Survey of Sweden, SueciaInstitut Cartogràfic i Geològic de Catalunya, EspañaBritish Geological Survey, Reino UnidoGeological Survey of Slovakia, EslovaquiaGeological Survey of Lithuania, LituaniaFederalni zavod za geologiju, Bosnia y HerzegovinaGeological Survey of Estonia, EstoniaLaboratório Nacional de Energia e Geologia, PortugalGeological Survey of Hungary, HungríaNorwegian Water and energy Directorate of Norway, Norueg

Transfer of deformation during indentation : Inferences from the post- middle Miocene evolution of the Dinarides

Understanding the structural and kinematic effects of indentation is still debated due to the large number of competing mechanisms associated with the complex orogenic build-up. Among the many examples available worldwide, the evolution of the Adriatic continental microplate in the Mediterranean domain provides one of the best places to understand the mechanics of indentation. This understanding is hampered by the lack of structural and kinematic data in the Dinarides, an orogen situated at the critical transition between the Alps, Albanides and Hellenides, and across the Adriatic margin of the Apennines. We have studied the less known area of the central and south-eastern Dinarides by focussing on collecting a new kinematic dataset for structures formed during the Adriatic indentation, which postdates the main Late Jurassic – Paleogene orogenic structuration. Our results are in agreement with previous interpretations of an early-middle Miocene period of extension that affected the entire orogen across its strike and is incompatible with indentation effects in the studied parts of the Dinarides. More importantly, we demonstrate for the first time that the post- middle Miocene Dinarides deformation was characterized by a coherent regional system of large offset dextral strike-slip faults, which transfer gradually their offsets to thrusts and high-angle reverse faults. The overall deformation transfer mechanism can be described as a special class of continental restraining bends or stepovers, whose geometry is controlled by rheological distribution. The integration of our results in the larger geodynamic context shows that the post-middle Miocene Dinarides fault system accommodates the differential motion between the N- to NE-wards Adriatic indentation and the rapid S- to SW- ward movement of a Hellenides area situated SE of the Kefalonia Fault, driven by the Aegean slab-roll back

Kinematics of foreland-vergent crustal accretion : inferences from the Dinarides evolution

One of the most common observation in Mediterranean areas is the migration of contractional deformation and associated slabs through time towards external orogenic areas, associated with lower plate crustal accretion. The Dinarides orogen of Central Europe is an optimal place to study such a sequence of contractional deformation. Compared with other areas, contraction in the Dinarides was less overprinted by subsequent extension, while a remnant of the subducted slab is observed in a far external orogenic position. Understanding the deformational evolution of the Dinarides is hampered by the reduced availability of kinematic studies. Therefore, we have performed a surface kinematic study in the external parts of the Dinarides. By correlating with available geophysical and evolutionary constraints, we constructed two large-scale, kinematically controlled regional transects. The results demonstrate a long-lived evolution of shortening that affected the Dinarides lower orogenic plate. While the Late Jurassic?earliest Cretaceous deformation was associated with an earlier obduction moment, the latest Cretaceous onset of continental collision has gradually focused deformation at inherited rheological weakness zones. We show that shortening was interrupted by a period of Miocene extension that affected all orogenic areas and created the Dinarides Lake System. The extension was followed by renewed shortening, that started during the latest Miocene and remains presently active, whose kinematics in the central and SE part of the Dinarides is revealed for the first time by our study. These results indicate a lower plate crustal accretion mechanism that was spatially and temporally connected with gradual slab-retreat in the Dinarides

Kinematics of foreland-vergent crustal accretion : inferences from the Dinarides evolution

One of the most common observation in Mediterranean areas is the migration of contractional deformation and associated slabs through time towards external orogenic areas, associated with lower plate crustal accretion. The Dinarides orogen of Central Europe is an optimal place to study such a sequence of contractional deformation. Compared with other areas, contraction in the Dinarides was less overprinted by subsequent extension, while a remnant of the subducted slab is observed in a far external orogenic position. Understanding the deformational evolution of the Dinarides is hampered by the reduced availability of kinematic studies. Therefore, we have performed a surface kinematic study in the external parts of the Dinarides. By correlating with available geophysical and evolutionary constraints, we constructed two large-scale, kinematically controlled regional transects. The results demonstrate a long-lived evolution of shortening that affected the Dinarides lower orogenic plate. While the Late Jurassic?earliest Cretaceous deformation was associated with an earlier obduction moment, the latest Cretaceous onset of continental collision has gradually focused deformation at inherited rheological weakness zones. We show that shortening was interrupted by a period of Miocene extension that affected all orogenic areas and created the Dinarides Lake System. The extension was followed by renewed shortening, that started during the latest Miocene and remains presently active, whose kinematics in the central and SE part of the Dinarides is revealed for the first time by our study. These results indicate a lower plate crustal accretion mechanism that was spatially and temporally connected with gradual slab-retreat in the Dinarides

Transfer of deformation during indentation: Inferences from the post- middle Miocene evolution of the Dinarides

Understanding the structural and kinematic effects of indentation is still debated due to the large number of competing mechanisms associated with the complex orogenic build-up. Among the many examples available worldwide, the evolution of the Adriatic continental microplate in the Mediterranean domain provides one of the best places to understand the mechanics of indentation. This understanding is hampered by the lack of structural and kinematic data in the Dinarides, an orogen situated at the critical transition between the Alps, Albanides and Hellenides, and across the Adriatic margin of the Apennines. We have studied the less known area of the central and south-eastern Dinarides by focussing on collecting a new kinematic dataset for structures formed during the Adriatic indentation, which postdates the main Late Jurassic – Paleogene orogenic structuration. Our results are in agreement with previous interpretations of an early-middle Miocene period of extension that affected the entire orogen across its strike and is incompatible with indentation effects in the studied parts of the Dinarides. More importantly, we demonstrate for the first time that the post- middle Miocene Dinarides deformation was characterized by a coherent regional system of large offset dextral strike-slip faults, which transfer gradually their offsets to thrusts and high-angle reverse faults. The overall deformation transfer mechanism can be described as a special class of continental restraining bends or stepovers, whose geometry is controlled by rheological distribution. The integration of our results in the larger geodynamic context shows that the post-middle Miocene Dinarides fault system accommodates the differential motion between the N- to NE-wards Adriatic indentation and the rapid S- to SW- ward movement of a Hellenides area situated SE of the Kefalonia Fault, driven by the Aegean slab-roll back

Integration of geohazards into urban and land-use planning. Towards a Landslide Directive. The EuroGeoSurveys Questionnaire

Exposure to hazards is expected to increase in Europe, due to rapid population growth in urban areas and the escalation of urbanization throughout many countries. In the framework of the European Geological Surveys (EGS), the Earth Observation and Geohazards Expert Group (EOEG) has carried out a survey based enquiry regarding the integration of geohazards (earthquakes, volcanoes, landslides, ground subsidence, floods and others) into urban and land-use planning. Responses from 19 European countries and 5 regions reveal heterogeneous policies across national borders. 17% of the countries have not yet implemented any legal measures to integrate geohazards into urban and land-use plans and half of the participating countries have no official methodological guides to construct geohazard maps. Additionally, there is a scarce knowledge about real social impacts of geohazards and resulting disasters in many of the countries, although they have a significant impact on their national economies. This overview stresses the need for a common legislative framework and homogenization of the national legislations as well as mutual guidelines which adopt the principles applicable to the management of geohazards and explain the process to be followed in the production of hazard documentation. This is especially relevant in case of landslide and subsidence hazards; although those are of great importance in Europe, there are no common guidelines and practices similar to Directive 2007/60/EC on the assessment and management of flood risk. Based on their expertise, EuroGeoSurveys (EGS) have the potential to coordinate this activity in European geohazard guidelines and to promote the interaction among stakeholders