Upscaling and downscaling landslide susceptibility maps

Although without official standardization, landslide susceptibility models (LSM) have entered preliminary stages of design and planning practice worldwide. As design and planning itself undergoes from lower to higher level of detail, different scales of LSM apply. Nevertheless, the LSMs are mainly produced in regional scales, whereas national and local are rarely available. Limitations of downscaling and upscaling LSMs are considered herein, by comparing LSMs coming from continental scale on one hand, and regional scale on the other, while the validation was performed using national scale model (Figure 1) at 30 m pixel resolution. Pan- European model (Wilde et al. 2018) is downscaled from 200 to 30 m pixel resolution using re-gridding method based on various interpolation techniques (linear, spline, Kriging) over the area of the City of Doboj in Republic of Srpska (Bosnia and Herzegovina). The LSM for the City of Doboj (Sandić et al. 2023) was upscaled from 5 to 30 m resolution using various resampling techniques (nearest neighbor, bilinear interpolation and cubic convolution). All maps were made using heuristic or combined heuristic approaches with standard landslide conditioning factors as raster inputs (geological, geomorphological, environmental, etc.). The best performing downscaling option was spline interpolation, while cubic convolution gave the best match against the referent LSM for the upscaling. Other downscaling variants tend to pixelate the map at 30 m resolution, whereas upscaling was not that considerably affected by technique choice. For large scale urban planning and preliminary design it is important to avoid pixilation as much as possible and smoothen the susceptibility classes so they can be compared against various elements, such as road and railway network features (higher-order curves, bridges, tunnels) and urban fabric footprints (housing, industrial, infrastructure). Results indicate that downscaling can be misleading and should be avoided if there is time and resource to perform appropriate local or regional scale LSM

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

Landslade hazard and risk assessment for different level of spatial planing in the Republic of Srpska, B&H

Територија Републике Српске је у посљедних десетак година веома угрожена активирањем нових и реактивирањем старих клизишта. Она својим дјеловањем наносе огромне материјалне штете, па и људске жртве, те је неопходно озбиљније третирање и дјеловање у борби са овим природним хазардом. Чест проблем јесте одговорност, тј. надлежност институција из ове области и недостатак у законској регулативи која готово никако или само површно обрађује област хазарда и ризика од клизишта. Усљед непостојања праксе и усвојених методологија које су у примјени у свијету, циљ и предмет ове дисертације јесте процјена склоности, хазарда и ризика од клизишта за различите нивое просторног планирања у Републици Српској. Методе процјене рађене су за различите територијалне цјелине у Републици Српској и за различите нивое планирања - од нивоа националне процјене у размјери 1:100.000, локалног нивоа у размјери 1:25.000 па све до детаљног нивоа у размјере 1:5.000. Извршеним процјенама добијени су модели – карте склоности, хазарда и ризика од клизишта у GIS окружењу, урађена према савременим смјерницама и међународним препорукама из ове области. Након сваке од урађених процјена, извршена је квантитативна верификација сваког добијеног модела, односно провјера његове тачности. Као полазна основа урађена је процјена склоности ка клижењу за ниво цјелокупне територије Републике Српске у размјери 1:100.000. Овакав вид процјене може се користити за ниво Просторног плана Републике Српске. Затим је рађена процјена склоности ка клижењу за територију Града Зворника, у размјери 1:25.000. На овом нивоу вршена је упоредна процјена са два различита методолошка приступа, хеуристичког AHP приступа и статистичког LSA приступа. Добијени резултати су показали да LSA приступ даје нешто боље резултате. Процјена у овој размјери одговара нивоу Просторног плана јединица локалне самоуправе, односно нивоу општина и градова. У размјери 1:5.000, на детаљном нивоу, процјена је рађена за дио територије урбаног дијела Града Добоја. Процјена прати цјелокупан процес, почевши од склоности ка клижењу, односно квази – хазарда, изложености, затим угрожености елемената ризика, па све до процјене ризика. Примјењен је детерминистички приступ, односно процјена базирана на методи бесконачне косине (SINMAP модел) у GIS окружењу. Резултати добијени процјенама на овом нивоу могу се користити у урбанистичком планирању, за израду акционих планова упозорења, у системима одлучивања приоритета за санацију и сл. Недвосмислено се може закључити да овакве процјене морају бити интегрални дио просторно планских и урбанистичких докумената, а све у циљу превентивног дјеловања, правилног третмана ризика од клизишта и управљања истим.The territory of the Republic of Srpska has been in great danger over the last ten years by activating new landslides and reactivating old landslides. That cause enormous material damage, including human casualties, and require more serious treatment and action to combat this natural hazard. A common problem is accountability, ie the competence of institutions in this field and the lack of legal regulation, that almost completely or superficially addresses the area of landslide hazards and risks. Due to the lack of practice and adopted methodologies that are applicable in the world, the aim and subject of this dissertation is the assessment of landslide susceptibility, hazard and risk for different levels of spatial planning in the Republic of Srpska. Assessment methods were developed for different territorial units in the Republic of Srpska and for different levels of planning - from the national assessment scale of 1:100.000, the local level at 1:25.000 to the detailed level at 1:5.000. The map of landslides susceptibility, hazard and risk in GIS environment, made according to modern guidelines and international recommendations in this field were estimated. After each of the assessments, a quantitative verification of model obtained was performed, i.e. verification of its accuracy. In the first step, for the territory of the Republic of Srpska, was performed the landslide susceptibility assessment in the scale 1:100.000. This kind of assessment can be used for the level of Spatial Plan of the Republic of Srpska. Then, the landslide suceptibility assessment of the Zvornik City was made, in the scale of 1:25.000. At this level, a comparative assessment was performed with two different methodological approaches, the heuristic AHP approach and the statistical LSA approach. The obtained results showed that the LSA approach gives slightly better results. The estimation in this scale corresponds to the level of the Spatial Plan of local government units, or level of municipalities and cities. In the scale of 1:5.000, at a detailed level, the assessment is done for part of the territory of the urban part of the of Doboj City. The assessment follows the whole process, starting from the landslide susceptibility, i.e. quasi - hazard, exposure, then vulnerability of element of risk, until the risk assessment. А deterministic approach was applied, that is, an assessment based on the infinite slope method (SINMAP model) in the GIS environment. The results obtained from assessments at this level can be used in urban planning, for the development of different action plans, in decision-making systems for prioritizing location for remediation, etc. It can be unequivocally concluded that such assessments must be an integral part of spatial planning and urban planning documents, all with the aim of preventive action, proper landslide risk management

Terenske metode određivanja nosivosti vertikalno opterećenog šipa u peskovitom tlu

U radu su prikazane najčešće metode proračuna nosivosti vertikalno opterećenog šipa, zasnovane na rezultatima terenskih istraživanja (probnom opterećenju šipa i opitima statičke penetracije - CPT). Za analizu su iskorišćeni podaci dobijeni od starne Instituta za ispitivanje materijala Srbije - IMS, za dve relativno bliske lokacije u Novom Beogradu (blokovi 29 i 32). U pitanju je teren izgrađen od aluvijalnih sedimenata sličnih litoloških i geomehaničkih karakteristika

The rainfall-induced landsliding in Western Serbia: A temporal prediction approach using Decision Tree technique

This paper focuses on modeling rainfall-induced massive landsliding in the Western Serbia in the 2001-2014 period. The motivation for conducting the study was the rainfall-induced flooding and landsliding that took place across most of the Serbia and Bosnia and Herzegovina in May 2014, and had devastating effects, including human casualties, and destruction of natural and urban environment. In the first part of the study, the general analysis was conducted. It includes a wide area (70,000 km(2)), wherein spatial rainfall patterns were identified using the monthly rainfall data from the 2001-2014. Areas that have higher monthly precipitation than the baseline monthly rainfall (1961-90) were outlined. One location within these zones was chosen as critical Loznica in Western Serbia. The area of Loznica was further examined: comparison between local daily rainfall and local landslide events recorded in 2001-2014; correlation between specific rainfall conditions, i.e. cumulative rainfall for different time windows, and the landsliding events in the specified period; identification of additional non-reported rainfall events that were potentially responsible for landsliding; analyses of the rainfall thresholds and temporal rainfall distribution. The Decision Tree algorithm was used to identify rainfall conditions that triggered landslides in the specified period. It was hypothesized that short-term rainfall has less influence on massive landsliding than the mid/long-term rainfall. Unlike other black-box techniques, Decision Tree-based modeling gives a good insight into the thresholding process. Namely, it was possible to follow the Decision Tree structure and reconstruct the critical cumulative rainfall distribution and thresholds that have led to landsliding. The main findings suggest that a high-yield mid-term rainfall (2 and 3-day rainfall) are the most important for massive landsliding, while long-term cumulative rainfall (30-day) has some additional influence in the case of Loznica. The upper threshold values extracted from the original, and appended synthetic rainfall events were about 30 mm for 2- and 3-day rainfall, and 140 mm for 30-day rainfall, which is in agreement with the evidence of the May 2014 event. It is thereby shown how proposed approach can be used preliminarily in the case of rainfall/landslide data scarcity for rough threshold estimation and extrapolation. However, limitations regarding utilization of such data must be accounted for

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