Editors: Dr Biljana Abolmasov, University of , Faculty of Mining and Geology Dr Miloš Marjanoviđ, , Faculty of Mining and Geology Uroš uriđ, MSc, University of Belgrade, Faculty of Civil Engineering

Proceedings of the 2nd Regional Symposium on LANDSLIDES in the AdriaƟ c-Balkan Region, ReSyLAB, Belgrade 14-16 May 2015

University of Belgrade, Faculty of Mining and Geology May 2017

PUBLISHER: University of Belgrade, Faculty of Mining and Geology FOR PUBLISHER: Prof. Dušan Polomēiđ, Dean COVER DESIGN: SrĜan KrsƟ đ PRINTED BY: Sapient Graphics ISSUED: 250 Copies

FRONT COVER PHOTO: Landslide Leva Reka, , (by Biljana Abolmasov) BACK COVER PHOTO: Landslide Leva Reka, Kraljevo, Serbia, UAV photo (by Dragan Milovanoviđ and Stefan Miljkoviđ)

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REGIONAL Symposium on Landslides in the AdriaƟ c-Balkan Region (2 ; 2015 ; Beograd) Proceedings of the 2nd Regional Symposium on Landslides in the AdriaƟ c-Balkan Region, RESYLAB, Belgrade 14-16 May 2015 [Elektronski izvor] ; editors Biljana Abolmasov, Miloš Marjanoviđ, Uroš uriđ / editors Biljana Abolmasov, Miloš Marjanoviđ, Uroš uriđ. - Belgrade : University of Belgrade, Faculty of Mining and Geology, 2017 (Belgrade : Sapient Graphics). - 1 elektronski opƟ ēki disk (CD-ROM) ; 12 cm

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ISBN 978-86-7352-296-8 a) ʶ̛̛̣̹̯̌̚ - ʯ̶̨̛̛̬̦̍ b) ʶ̨̛̭̦̖ - ʯ̶̨̛̛̬̦̍ COBISS.SR-ID 234417420 Proceedingsofthe2ndRegionalSymposiumonLandslides,Belgrade,2015

LandslideeventsinSerbiainMay2014:AnOverview

MilošMarjanoviđ(1,2),BiljanaAbolmasov(1),Urošuriđ(3),SnežanaBogdanoviđ (1),Michael Krautblatter(2) 1)UniversityofBelgrade,FacultyofMiningandGeology,DepartmentofGeotechnics,Belgrade,ušina7,+381113219224 2) Technische Universität München, Faculty of Civil, Geo and Environmental Engineering, Chair of Landslide Research, Munich 3)UniversityofBelgrade,FacultyofCivilEngineering,DepartmentofGeotechnicalEngineering,Belgrade  

Abstract In this paper we overview the landsliding missing temporal dimension, as they all only compile aftermath caused by a 100Ǧyear rainfall maximum in reportedhistoricevents,thereforefailingtoserveasgood WesternandCentralSerbiainmidMay2014,byapplying support for eventǦdriven analyses. This is especially various spatial analyses. The extreme character of the importantinthecasesofextremeevents,whenmassive event is well depicted throughout the damage and cost landslidingexceedstheboundariesofexpected,andleads estimations and explored for their spatial patterns and touncommonmechanismsatunprecedentedrates.One relations to other characteristics, such as landslide such episode stroke Serbia during the extreme rainfall typology, metrics (surface area, volume, depth), rock event,thataffectedtheentireBalkanregion,inmidMay types,etc.Analysesarealsoperformedonadministrative 2014. level,permunicipalityandbiggersettlements,aswellas HeavyprecipitationpeakedonMay14Ǧ16,asCyclone road communications, to enhance the overview of TamaraswepttheregioninWestǦEastdirection,passing economic and social effects of the event. We herein throughCroatia,BosniaandHerzegovinaandSerbia.The exploit only reported landslides and their effects, while rainfall locally exceeded monthly rates up to 4 times in the realistic estimates are only discussed. Shallow slipǦ these 3 days. In Western and Central Serbia, daily slides were the most dominant, although considerable precipitation onMay15exceededthenormalaverageof numberofflows,whichareuncommonforclimaticand the entire month (RHMSS 2014). Several rain gauges in environmentalconditionsinSerbia,wasalsoreported.As Belgrade,  and Loznica, registered over 100 a result, extreme landsliding, directly affected 34 mm/day, which is the highest daily precipitation total municipalities, wherein municipalities of,ukarica, everrecordedinSerbia,sincethebeginingofrecordingin ,,andLoznicahadthehighest 1888. The rainfall event was concentrated on the Sava abundance of landslides per municipality area. Analysis River catchment and partly the Velika Morava River oflandslidebufferszonessuggestthatsignificantamount system. The first torrential floods appeared in BosniaǦ of road communications was heavily affected. Most Herzegovina,andWesternandCentralSerbia,whilethe importantly, the buffer shows high percentage of the flood wave started within the following days along affecting the population for several landslides. These the Sava River. The first landslides (debris/earthflows) resultsarevaluablesupplementstothegeneralestimates occurredonMay15,andearlyestimatesoftheirnumber performedduringtheRNA(RecoveryNeedsassessment) were in the order of hundreds (WorkGroup2 2014, reportingstage. UNDAC2014).   Keywords rainfall, landslides, Cyclone Tamara, spatial Landslidingeventandaftermathoverview analysis Such a massive event required a quick response and           immediate mapping and assessment campaigns.       Geological surveys of Serbia and domestic/foreign Introduction experts, as well as international working groups (the In climate changing conditions, the Balkan region is European Union, the United Nations and the World witnessing increased landsilidng activity in the past Bank) have initialized inventorying on a municipality decade. Precipitation patterns are clustered (Bajat et al. level.Initiallystandardized,thelandslidereportswereto 2013),whereaswetareasreceiveevenmoreprecipitation containallthenecessarypiecesofinformation:location, anddryingareasevenless(KleinTankandKönnen2003). metrics, type, mechanism, activation date, previous Therefore, rainfallǦtriggered landslides are meeting activity stage, estimated damage/cost and prognostic necessary conditions for becoming more abundant. crossǦsections. After further harmonization of location Unfortunately, there are no systematic overviews of and classification standards, these reports were used in landslide events in Serbia. Existing inventories are thespatialanalyses.

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M.Marjanovi©,B.Abolmasov,U.0uri©,S.Bogdanovi©,M.Krautblatter–LandslideeventsinSerbia…

be considered uncommon in normal mass movement events.TotalremediationcostestimatesrangeuptoRSD 300millionperindividuallandslides,whichisequivalent toEUR2.5million.  Table 1 Engineering Geological units enlisting rock types that hostedthemostofthelandslides(count>20). ID rocktype count 6 sand,clay,gravel(alluvialͲproluvialcomplex) 30 20 Cretaceousflysch 26 37 Paleozoicflyschcomplex 24 24 CretaceousflyschͲlikecomplex 23 38 PaleozoiclowͲcrystalineschist 21  Forthepurposeofrocktyperelationstolandslides, we overlaid the landslide data to archived Engineering Geological Map 1:500000 (,ubrilovi© 1969). Regarding these Engineering Geological controls, it is evident that landslides dominated in certain rock types, primarily proluvial complexes, which is directly related to debrisflows initiation. Weathered flyschǦlike complexes (labeled 20, 37, and 24; mostly composed of alternating conglomerateǦsandstone,marl,andshale)andweathered lowǦcrystalline Paleozoic schists (labeled 38) expectedly hostedmanyreportedlandslides(Fig.1).Saturatingtheir  thick detritus was critical for appearance of shallow Figure1LandslidesfollowingtheMay2014rainfallandrelevant landslides,whichwerethemostabundant. Engineering Geological units (rock types exampled in Table 1  areheregivenbytheirIDlabelsinwhite).Thetoneofeachunit SocioͲeconomicelementsoverview depends on the landslide count (intense tones have more landslides).Encircledareaistheareaofinterestchosenforthe Wefurtheranalyzedmunicipalitiesthatwereaffectedby analysis. landsliding, i.e. those that had at least one landslide occurrenceovertheirterritory. The total of (345) landslides were reported (Fig. 1), The following municipalities suffered the greatest including:34debrisflows,33debrisslides,34earthflows, damage to landsliding (Fig. 3a): Kraljevo, Mionica 223 earthslides, and 8 rockfalls, while 37 instances ,andOse«ina,followedby,, remained unclassified (Fig. 2a,b). Earth slides were the Užice, , Para©in, etc. However, significant largest in volume (also the biggest in area and the number of reported instances did not include the total deepest)ofalllandslidetypes,as59of70landslidesthat 3 remediationcostestimates(30%0r106/345).Thisislikely were larger than 10000 m  belong to this type (Fig. 2a). the reason why these estimates are not that well Majority of the landslides (80% or 277/345) were correlatedwiththeactuallandslideabundanceorrelative relatively shallow (<5 m). All reported landslides are landslide areaǦthe total area of all landslides in a identified as entirely new, caused by the May 2014 municipalitydividedbythesizeofthatmunicipality(Fig. rainfall,butthisfindingisarguableduetotheabsenceof 3b). The latter is probably the most realistic estimate reliable activation date estimates in many reports. The (than for instance the landslide count) as it normalizes mostdamagingweretheearthslidesanddebrisflows(Fig. the surface area of landslide by the area of the 2b). municipality.Itistherefore,morejustifiedtosaythatthe Relative damage was not equally distributed: 108 landsliding hotspots and the hotspots of the economic high, 84 low, 115 medium, but it is well correlated with impact due to landsliding where concentrated on landslide volumes (Fig. 2c). In comparison to the municipalities in Western Serbia: Loznica, Krupanj, and estimated remediation cost, relative damage was locally Mionica. Relations between the relative damage and overestimatedinsomecases,mostlyintheBelgradeCity landslidevolumealsosupportthisview(Fig.2c). area wherelandslides depicted in redhavehigh relative  damage estimates, while actual costs were estimated to  reasonably lower values (Fig. 2d). The opposite, underestimatedcostsareapparentusuallyinrelationto earthslides,whichisunderstandablegiventhatthesecan

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 Figure2Scaledlandslideinstancesplots:a)landslidetypesvs.volume,b)landslidetypesvs.estimatedremediationcosts,c)estimated relativedamagevs.landslidevolume,d)estimatedrelativedamagevs.estimatedremediationcosts.  We further analyzed the socioǦeconomic influence dasymetricmapat100mresolutionisnowavailablefor ofthelandslidebufferzoneontheroadcommunication all municipalities in Serbia for free at: infrastructureandsettlements.Assumingthebufferzone http://osgl.grf.bg.ac.rs/. Consistently with the preceding around each individual landslide, we acknowledged the analyses we used only affected municipalities for critical radius of 10km (the greatest reported landslide overlaying the landslide data with dasymetric data length). Overlaying the road network to the landslide (relative population density at 0Ǧ100% range). By buffer gives a preliminary insight into the affected extractingdasymetricvaluespereachlandslide,wewere infrastructure (Fig. 3c). Summing the effect of landslide abletoscalelandslideinstancesplot(Fig.3d).Theresults vicinityovertheselinearfeaturesleavesdefinestheroads show that around 20% of population was directly or closesttolandslidesasthemostaffected.Onlytheroad indirectlyinfluencedbylandslides(superponingtoother network in the affected municipalities was observed. economic and ifrastructure issues elaborated before). According to these calculations, around 975 km of the Fortunately, small percentage (around 4%) falls on highestrankroads(nationalandregional)fallswithinthe population that is dense (more than 50% of the total most critical class (<1km away from the landslide). We populationofeachmunicipality).Thecriticalbufferof10 followedthesameanalogyfordepictingthemostaffected km however, split the population to 70Ǧ30% split, largersettlements,i.e.cities.Overlaying(Fig.3c)suggests wherein 70% of considered population remains in the that Loznica, Belgrade, Užice, Krupanj remain the wider critical zone. These results confirmed that wider hotspots in terms of endangered settlements (given in areas of Loznica, Belgrade, Užice, Krupanj are true gradual tones from darker to lighter, depending on the hotspots of socioǦeconomic effects of the May 2014 valueofthetotallandslidevicinity). landslideevents. Finally,weestimatedtheaffectedpopulationbased  on the realistic population distribution from 2006. The 

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 Figure3Choroplethsandscaledplots:a)Municipalitytotalremediationcosts(darkertonesdepicthighercosts),b)relativelandslide area(landslideareaincomparisontothemunicipalityarea),c)affectedroadcommunicationsandcitiesinvicinityoflandslides,d) impactonrealisticpopulationdistribution(relativedensity in%perpixel isgivenasthescaleforindividuallandslideseffectson population).  Conclusions probably involved only the most threatening examples, whereinsomepropertyorinfrastructurewasdamaged.It This overview of the landslide events takes into account          isnecessarytofurtheranalyzetheeventingreaterdetail, spatial patterns and relationships of landslide       i.e. to endeavor detailed and more general landslide characteristics and its socio economic aftermath. To the    Ǧ     inventorying of the entire affected area to properly best of our knowledge, it is a unique summary of the            characterizetheMay2014eventandrelateittopastand event. The scale, typology and metrics of the landslide          future events. Our current hypothesis, based only on events are summarized and some particular relations reported landslides, already suggests that it was an discovered, such as typology vs. metrics and costs, and          extreme event in terms of scale, and typology of relative damage vs. metrics and costs. The second part of           occurrences,aswellasitssocioǦeconomicimpacts. the research was concentrated on soci0 economic effects      Ǧ    upon administrative entities, i.e. municipalities, cities, Acknowledgements population and road infrastructures. Some interesting relationsrevealthelandslidinghotspotsnotonlyeventǦ This work was supported by the project of TUM wise, but also costǦwise and in respect to other socioǦ University Foundation Fellowship and the project of economicinfluences.Itisfinallyimportanttoemphasize MinistryofScienceoftheRepublicofSerbia(TR36009). thatalltheanalyseswerebasedonreporteddata,butwe Hereby we thank Geological Survey of for leaving their have found enough evidence to believe that the actual dataatdisposal.AspecialthanksgoestoVukašinVu«evi© landslidng (unreported occurrences) was much more fromMinistryofMiningandEnergyofSerbia,andJelka abundant and widespread. Reported occurrences Kruši©andDraganaPetrovi©fromUniversityofBelgrade,

242 Proceedingsofthe2ndRegionalSymposiumonLandslides,Belgrade,2015

FacultyofMiningandGeologyforhelpingusretrievethe Republiēki Hidrometeorološki Zavod, analoguedata. http://www.hidmet.gov.rs/podaci/meteorologija/ciril/Maj.pdf  Accessed23March2015(inSerbian) References UNDACͲUN Disaster Assessment and Coordination (2014) End of Mission Report. United Nations Office for the Coordination of Bajat B, Pejoviđ M, Lukoviđ J, Manojloviđ P, Duciđ V, Mustafiđ S Humanitarian AffairsͲOCHA, p 78, (2013) Mapping average annual precipitation in Serbia (1961– https://www.humanitarianresponse.info/system/files/document 1990)byusingregressionkriging.Theor.Appl.Climatol.112:1Ͳ13 s/files/Final%20UNDAC%20Report%20Ͳ ubriloviđP(1969)Explanationoftheengineering–geologicalmap %20Serbia%20Floods_May2014.pdf,Accessed23March of SFR Yugoslavia scale 1:500 000. Federal Geological Institute, WorkGroup2ͲSerbianGovernment,EU,UNSerbiaandWorldBank Belgrade,p137 (2014)ReportonNeedsAssessmentͲSerbiafloods2014.Serbian Klein Tank AMG, Können GP (2003) Trends in Indices of Daily Government, EU, UN and World Bank, Belgrade, Serbia, p 163, Temperature and Precipitation Extremes in , 1946Ͳ99. http://ec.europa.eu/enlargement/pdf/press_corner/floods/20 JournalofClimate16:3665Ͳ3680 140715-serbia-rna-report.pdf,Accessed23March2015 RHMSSͲRepublic HydroͲMeteorological Survey of Serbia (2014)  MeseēnibiltenzaSrbijuͲmaj2014(QFͲEͲ002).RepublikaSrbija, 

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