ACTA GEOGRAPHICA GEOGRAFSKI ZBORNIK SLOVENICA 2015 55 1 ACTAGEOGRAPHICA SLOVENICA GEOGRAFSKIZBORNIK 55­1 2015 2 ZNANSTVENORAZISKOVALNI CENTER SLOVENSKE AKADEMIJE ZNANOSTI IN UMETNOSTI GEOGRAFSKI INŠTITUT ANTONA MELIKA — RESEARCH CENTRE OF THE SLOVENIAN ACADEMY OF SCIENCES AND ARTS ANTON MELIK GEOGRAPHICAL INSTITUTE ACTAGEOGRAPHICA SLOVENICA GEOGRAFSKIZBORNIK 55­1 2015 LJUBLJANA 2015 ACTA GEOGRAPHICA SLOVENICA/GEOGRAFSKI ZBORNIK 55-1 2015 ISSN: 1581-6613 COBISS: 124775936 UDC/UDK: 91 . Geografski inštitut Antona Melika ZRCSAZU 2015 I/ : Michael Bründl (Switzerland), Rok Cigli„ (Slovenia), MatejGabrovec (Slovenia), Peter Jordan (Austria), Drago Kladnik (Slovenia), Bla. Komac (Slovenia), Andrej Kranjc (Slovenia),Dénes Lóczy (Hungary), Simon McCharty (United Kingdom), Slobodan Markovi” (Serbia), Milan Orožen Adami„ (Slovenija), Drago Perko (Slovenia), Marjan Ravbar (Slovenia), Ale’ Smrekar (Slovenia), Annett Steinführer (Germany), Mimi Urbanc (Slovenia), Matija Zorn (Slovenia). E --C / : Bla. Komac; blaz.komac@zrc-sazu.si E/ : Drago Perko; drago@zrc-sazu.si C/ : Matija Zorn; matija.zorn@zrc-sazu.si C/ : Mimi Urbanc; mimi@zrc-sazu.si C/ : Drago Kladnik; drago.kladnik@zrc-sazu.si C/ 9 Janez Nared; janez.nared@zrc-sazu.si C/ : Rok Cigli„ rok.ciglic@zrc-sazu.si C /9 Ale’ Smrekar; ales.smrekar@zrc.sazu E/ 9 Matja. Gerši„ / : Geografski inštitut Antona Melika ZRC SAZU I/ : Založba ZRC C-/ : Slovenska akademija znanosti in umetnosti A /N 9 Geografski inštitut Antona Melika ZRC SAZU, Gosposka ulica 13, SI – 1000 Ljubljana, Slovenija š -E / š : http://ags.zrc-sazu.si (E I N9 1581-8314/ I N9 1581 8314) O/ 9 Založba ZRC Novi trg 2, p.p. 306, SI – 1001 Ljubljana, Slovenija /9 +386 (0)1 4706464 F/ 9 +386 (0)1 4257794 E-/-9 zalozba@zrc-sazu.si A / :20“ / , 12,50“ /. C/ 9 Geografski inštitut Antona Melika ZRC SAZU Translations/9 DEKS, d.o.o. D/ 9 SYNCOMP, d.o.o. /9 Collegium Graphicum d.o.o. /9 400 copies/izvodov š š A/ J . š / 9 SCIE (Science citation index expanded, IF 2013: 0.750, 2012:0.484, 2011: 1.333, 2010: 0.346, 2009: 0.714), Scopus (SNIP 2013: 1.037, 2012: 1.475, 2011: 0.997, 2010: 0.164, 2009:1.047), CGP (Currentgeographicalpublications), Directory of Open AccessJournals, EBSCOhost, Electronic publishingCenter, Findin a library, GEOBASE Journals, GEODOK(Virtual GeographicLibrary Database), Geosource,JS (JournalCitationReports/ScienceEdition),OHSUElectronicJournals,Googlescholar,Geosciencee-Journals,FRANCIS,ERIHPLUS. F9 Cultural terraces, such as these in the Brkini Hills, are an important element of numerous Slovenian regions (photograph: Matev. Lenarčič). F9 Kulturne terase, kot te v Brkinih, so pomembna prvina številnih slovenskih pokrajin (fotografija: Matev. Lenarčič). ISSN: 1581-6613 UDC – UDK: 91 Number – številka: 55-1 Year – leto: 2015 C e Vebi a Anita JERŠE, Andrej GOSAR, Mladen ŽIV I Mš  L 7 Makroseizmične raziskave vplivov lokalne geološke zgradbe na intenzitete izbranih potresov na širšem območju Ljubljane 20 Lučka AŽMAN MOMIRSKI, Drago KLADNIK BH 29 Terasirana pokrajina v Brkinih 50 Kristina KNIFIC, Štefan BOJNEC 59 Spremembe v strukturi uporabe zemljiš„ na kmečkih gospodarstvih na hribovitih podeželskih območjih 70 Nika RAZPOTNIK VISKOVI Eš 9 79 Vrednotenje razvojnega potenciala obmestnih kmetij – metodologija 90 Mimi URBANC, Primo GAŠPERI , Jani KOZINA G :š 99 Geografsko zamišljanje pokrajin: analiza fotomonografije Slovenske krajine 116 Piotr RA NIAK, Anna WINIARCZYK-RA NNIAK D  2008 E : 127 Nina ZUPAN I , Aleksander HORVAT, Simona SKOBE E  K š 139 Okoljski vpliv prašenja s terminala koprskega pristanišča za razsuti tovor na kmetijska tla 152 5 S ecia i eČ Wikia Janey NARED, Nika RAZPOTNIK VISKOVI , Bla KOMACA 161 Janey NARED, Nika RAZPOTNIK VISKOVI , Bla KOMACA 9 A , , 165 Axel BORSDORF, Oliver BENDER, Fides BRAUN, Andreas HALLER - A 173 6 MacroseisMicinvestigationsofthe geologicalsiteeffectsonintensitiesofselected earthquakesinthe greaterljubljanaarea MakroseizMičneraziskavevplivovlokalnegeološkezgradbenaintenziteteizbranihpotresovnaširšeMobMočjuljubljane Anita Jerše, Andrej Gosar, Mladen ŽivčiŤ Macroseismic investigations of the geological site effects onintensities of selected earthquakes in greater Ljubljana area DOI: http://dx.doi.org/10.3986/AGS.793 UDC: 550.34(497.451) COBISS: 1.01 ABStrACt:LjubljanaisoneofthreeregionswiththehighestseismichazardinSlovenia.Inadditionsoft sediments in the Ljubljana basin have a strong influence on seismic ground motion. We used macroseis­micdatatoinvestigatetheinfluenceoflocalgeologicalstructureonearthquakeintensitiesingreaterLjubljana area.WedeterminedintensitiesforelevenearthquakesaccordingtogroundclassificationbasedonEurocode 8 standard (EC8). the results showed a systematic increase in observed seismic intensities, determined accordingtoEuropeanMacroseismicScale(EMS-98),astheseismogeologicalcharacteristicsoftheground deteriorated. Onlyonegroundtype(D)showedslightly lowerintensitiesthan expected. this maybe due to some unrevealed geological and other factors, or because of very limited macroseismic data available for this particular ground type. KE WOrDS:EuropeanMacroseismicScale,intensity,macroseismicinvestigations,Eurocode8,seismic microzonation, Ljubljana basin the article was submitted for publication on May 9th, 2014. ADDrESSES: Anita Jerše Slovenian Environment Agency Seismology and Geology Office Dunajska 47, SI ) 1000 Ljubljana, Slovenia E-mail: anita.jerse@gmail.com Mladen Živčić, M.Sc. Slovenian Environment Agency Seismology and Geology Office Dunajska 47, SI ) 1000 Ljubljana, Slovenia E-mail: mladen.zivcic@gov.si Andrej Gosar, Ph.D. Slovenian Environment Agency Seismology and Geology Office Dunajska 47, SI ) 1000 Ljubljana, Slovenia and University of Ljubljana Faculty of Natural Sciences and Engineering Aškerčeva 12, SI ) 1000, Ljubljana, Slovenia E-mail: andrej.gosar@gov.si 1 Introduction Earthquakesareanaturalphenomenonthatcannotbeforecastedandcontrolled,butthatcanbewellobserved through the analysis of its effects. Macroseismic data consist of systematic descriptions of earthquakes' effects on humans, objects, buildings and nature. the amplitude of ground oscillation depends on earthquakes' source properties (magnitude, depth, distance, focal mechanism), on the impact of regional geology on the propagation of seismic waves, and on the local geological condition known as site effects. In seismic hazard assessment for a site located on asoftgroundthevalueofground-motionaccelerationonabasesolidrockismultipliedbyacorresponding soil factor. the aim of this study is to evaluate the influence of local geological structure on certain earthquake intensities in thegreater Ljubljanaarea,based onthe ground classificationaccording toEurocode 8stan­dard(EC8)(SIStEN1998-1,2005;SIStEN1998-1/A101,2005).Forthepurposesofmacroseismicanalysis we evaluated macroseismic questionnaires, which are kept in our archive. In estimating intensity we fol­lowed the principles of the European Macroseismic Scale (EMS-98) (Grünthal 1998). Intensities were determined for areas with a radius not exceeding 5km, which were located on homogeneous ground in accordancetoEC8classification.Basedonthegeologicalmap,inscale1:100,000,anditsmapinterpreters, we divided geological substrate areas into five classes according to EC8. Data of three separate groups of earthquakeswasstatisticallyanalysed.Foreachgroupwehaveselectedthereferenceintensityofthecom­parative polygon, with which we compared the intensity in other polygons for the same earthquake. 2 Previous research of the influence of local geological structure on earthquake effects Seismicwaveamplificationinalluvialdepositshascontributedtodamageandlossoflifeinseveralrecent earthquakes, for example in Christchurch, 2011 (Bradley 2012) and in Emilia-romagna 2012 (Maugerietal.2013).Inareaswithcomplexgeologysiteeffectscanvarysignificantly(toshinawaetal.1997). Many techniques all over the world have been presented to investigate the relationship between intensi­tyandgeologicalsettingusingmacroseismicdata.thefirstsignificantstudyofthiskindwasmadeinNew ealand(Elderetal.1991;toshinawaetal.1997).AlsoinItalytherehavebeenseveralstudiesonthevari­ationofearthquakeseffectscausedbysiteeffects,forexampleinPalermo(Giammarinaroetal.2005)and rome(Cifellietal.2000;Sbarraetal.2012).InSlovenialargevariationsindamagetobuildingswereobserved in case of 1998 and 2004 Krn mountains earthquakes. they were explained mainly by soil-structure res­onance effects (Gosar 2007; Gosar 2010). Basedonrecentstudies,expertshadsuggested(Sbarraetal.2012)usingmacroseismicintensityresid­uals as a contribution to the elaboration of hazard maps. they found that the intensity also depends on soil variations with the depth and thickness of each layer. 3 Geological setting and ground classification based on EC8 in the greater Ljubljana area Ljubljana, which is one of three regions with the highest seismic hazard in Slovenia (Lapajneetal. 2001), is located in a shallow sedimentary basin filled with heterogeneous Quaternary deposits (Figure 1) with variousseismologicalproperties.Wedistinguishthreemainparts:theLjubljanaField(Ljubljanskopolje), the north part of the Ljubljana Moor (Ljubljansko barje), and surrounding hills. the bedrock of the basin is built of Permian and Carboniferous clastic rocks (claystones, sandstones, conglomerates) and partly ofMesozoic carbonaterocks. It outcrops on themargins ofthe hills. Ljubljana Field is covered by gravel deposits of the Sava river. Sand and gravel in the Ljubljana Moor are covered by lake and marsh sediments. In EC8 site effects of different ground types are expressed with coefficient s (soil factor), which tell ushowmuchgreaterthegroundaccelerationisexpectedincomparisonwiththereferencesolidrock.there Legend/legenda Paleozoic clastic rocks (sandstones, shales)/paleozojske klastične kamnine (peščenjaki, laporovci) Mesozoic rocks (limestones, dolomites, clastic rocks)/mezozojske kamnine (apnenci, dolomiti, klastične kamnine) tertiary rocksandsediments(sandstone,conglomerate,sand,silt,clay)/terciarnekamnineinsedimenti(peščenjak,konglomerat,pesek,melj,glina) Quaternary alluvium (gravel, sand)/kvartarna prod in pesek Quaternary clay, sandy clay, silt/kvartarna glina, peščena glina, melj Quaternary lacustrine and paludal sediments (peat, clay)/kvartarni jezerski in barjanski sedimenti (šota, glina) Urban area/urbano območje (čČ ) aresevengroundtypesdescribedbythestratigraphicprofilesandbythreequantitativeparameters:average shear-wavevelocityinthetopmost30mofsediments(.s,30),theresultofStandardPenetrationtest(Nspt) andtheundrainedshearstrength(cu).ForspecialgroundtypesS1andS2,soilfactorSisnotgivenandmust be determined by specific investigations. theinfluenceoflocalgeologicalstructureonseismicgroundmotionisgiveninamicrozonationmap. Basedonthe geological map(OGK 100)and themapinterpreterweexpandedtheseismicmicrozonation mapoftheMunicipalityofLjubljana( upančičetal.2004)togreaterLjubljanaarea(Figure2).theground is classified into five types: * A ) factor 1.00, * C ) factor 1.15, * D ) factor 1.35, * E ) factor 1.70, * S1–factor2.55. WeusedgroundclassificationbasedonEC8accordingtothebasicgeologicalmap( upančičetal.2004), wherethegeologicalandlithologicalstructureoftheLjubljanaareawastakenupbyOGK100,sheetKranj (GradandFerjančič1974),Ljubljana(Premru1983),Postojna(Buseretal.1967)andribnica(Buser1969). Since the printed map OGK 100 is made on a relatively weak geodetic basis, the accuracy in the digital format is also poorer. Consequently, on the digital map they declared accuracy of the borders at 50m. therefore,wehavetoconsiderthatobservers,whofilled-inthemacroseismicquestionnairesandarelocat­ed near the boundaries, may not be placed in the right class according to EC8. thesouthwesternpartofthestudyarea(LjubljanaMoor)belongstogroundtypeS1,mostoftheeast­ernandwesternpartoftheareabelongstogroundtypeA,centralparthasbeenclassifiedasgroundtypeC, butthere arealso smallerareas whichfall within groundtype D andE(Figure 2). Inthe greater Ljubljana area there is no ground type B or S2. 4 Macroseismic data collection and intensity assessment Effectsofearthquakesonhumans,objects,buildingsandonnatureareassessedbyintensity,whichisdescribed byanintensityscale.Inordertoassesstheintensity,thefirststepistogatherallthedescriptivedataavailable Legend/legenda Observers/opazovalci Polygons/poligoni Groundtype/tipital(EC8) 1 A 2 C 3 D 4 E !! ! ! 5 S1 ! ! ! !! ! Filocat:ifflrs rditlassificatifiiintensities.iindicate 05 1234 km Authorofthecontents/avtorvsebine:AnitaJerše Authorofthemap/avtorzemljevida:AnitaJerše Source/vir:ARSO,GURS,2012 © MKO,AgencijaRSzaokolje gure3Mapopoygonsonhomogeneousgroundaccong otheEC8con orwhchwedetermnedearthquake Ponts the onsotheobserve foraparticularlocation.thenwesortthedatabylocationandcomparethemwiththelistsofdiagnostic elementsandmakeadecisiononwhichprovidesthebestfit. AllmacroseismicquestionnairesarekeptinthearchivesofSeismologyandGeologyOffice.Macroseismic dataincludequestionnaires,receivedbymail,viaonlinewebformandbye-mail. WedeterminedintensitiesforselectedareasinLjubljanaaccordingtogroundclassificationbased onEC8.Eachdeterminedintensityreferstosmallareaswitharadiusnotexceeding5kmandareaswith homogeneousgroundaccordingtoEC8,otherwisetherangeofshakingeffectsreportedmaybevery largesincegeotechnicalconditionsofthegroundvary.Consequentlywedividedthegroundwhere observersresideintoseveralpolygons(Figure3)andforeachpolygonwedeterminedintensityoftheearth­quake.Wehaveclassified4polygonsonthegroundtypeS1,2ongroundE,6ongroundD,10ongroundC and8polygonsongroundtypeA. InestimatingtheintensitywefollowedtheprinciplesofEMS-98 (Grünthal1998). 5 Methodology and data analysis Formacroseismicdataanalysiswegathered17earthquakes(table1)whichoccurredbetween1998and2005 andwerestrongenoughforourpurposes.Fromthisgroupof17earthquakes,wethenused11ofthemwhich best fulfilled the following requirements: * that they occurred far enough from Ljubljana. In this case we can neglect the variations of epicentral distancebetweendifferentpartsofthecityandthuswecanseethedifferencesinintensitiesduetotheinflu­ence of geological substrates; * thatseismicwavesarecomingfromsimilardirections.theinfluenceofthegeologicalstructureontheprop­agation of earthquake waves is similar in this case; * that they reached maximum intensity at least V EMS, and in the Ljubljana area an intensity of at least IV-V EMS; * that there is sufficient macroseismic data available for them. InthecaseofearthquakeswhichoccurredinthevicinityofBrezovica(2002)andCerkno(2005)there were several successive aftershocks, for which we have characterized the effects together, since there was insufficient data to allow precise assessment of the intensity for each shock separately. research was conducted for three separate groups of earthquakes. First, we focused on earthquakes (fiveofthem)thatbestfulfilledtherequirements.theirdistancefromLjubljanaisbetween45and120km. Seismic waves of this group come to Ljubljana from the northwest. In the second group earthquakes do notfullfiltherequirementssowell(sixofthem).theirdistancefromLjubljanaisshorter,between10and 45km.Seismicwaveshaveinthesecasesdifferentarrivaldirections.theestimatedintensitiesofearthquakes in this group are slightly lower than in the first group. the third group represents all eleven earthquakes. We analysed1,296 questionnairesonseismiceffects, filled-in by616observers. We dealt with thegreater Ljubljana area, which extends in the south to Želimlje, in the north to trzin, Dragomer in the west and in the east to the village Volavlje (Figure 3). 6 Results and Discussion For each group we selected a comparative polygon with reference intensity and compared the inten­sityofotherpolygonswiththereferenceoneforeachearthquake. thenumberofallestimatedintensities is 224 and they are presented in table 2. In the table, beside intensities, there is also the number of questionnaires on which basis the intensi­tywasestimated. Intensities,whicharedefinedonlyonthebasisofonequestionnaire(markedred),were not used in the statistical analysis. In further research 160 intensities were used. In case when intensity is given as range for example IV–V EMS–98, we used the value of 4.5 for the calculation purpose. We chose the polygon on ground type C as comparative, since it has mean values of geomechanical parameters in relation to other ground types. In the group of all eleven earthquakes, we chose the third one(C 3)asthecomparativepolygon,inthegroupoffiveearthquakesthesecondone(C 2),andinthegroup of other six earthquakes the fifth polygon (C 5). the selected polygon contains data for all earthquakes, does not contain any data that a single observer has not felt the earthquake, and has approximate mean value of intensity compared to other polygons on the ground C. We did not select polygon C 4 as com­parative ground, because its values slightly deviate from the average. For each polygon we calculated the deviation from the reference intensity for each earthquake sepa­rately and deviations of mean values from the reference intensity, which are: arithmetic mean, median, mode and modified median, where we have assumed that information »not felt( is the smallest. When calculating arithmetic mean we excluded data »not felt«. First we made a statistical analysis of each individual polygon (table 3), and then for grouped poly­gons according to ground type by EC8 (table 4). the results on the selection of five earthquakes showed that deviations from the reference intensity increasedasthequalityofthesoildeteriorated(especiallyongroundtypeE).However,theresultsofground type D deviate from others, since we would expect higher values than on ground C and not lower. this may be due to unrevealed geological or other factors. () () () () Č čČ č Č | questionnaires of five earthquakes 531 | questionnaires of eleven earthquakes 1296 | of all questionnaires 1849 () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () C_3 comparative III–IE (3) E (3) IID (6) E (7) IE (6) IV–E (8) IE (3) E (4) IE (4) IE (2) IE (10) polygon ()() () () () () ()() () () () () () () () ()() () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () ()() () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () ()() () () ()() () () () () () () () ( ) ( ) ( ) ( ) ( ) ( ) () () () () () () () () () () () () () () () () () () () () () () () () () () () () resultsonthetotalofelevenearthquakesshowasimilarrisingtrendofdeviationsfromthereference intensity as with analysis on five earthquakes. On ground D we got higher arithmetic mean of then on the ground C, but the mode is negative. In table 5 we present number of cases when intensity of earthquakes is smaller, greater or equal to thereferenceintensityongroundtypeCchosenascomparativeground.Blueindicatesintensitiesthatare prevailing on each ground. For the group of five earthquakes the results showed an increase in the intensities of earthquakes as the quality of the soil deteriorated. type A has more low intensities than high. the intensities of earth­quakesongroundC aremore equallydistributedwhichwasexpected. Ground typeE showed more high intensities than low and as well ground S1. Ground type S1 has also more high intensities than ground E, which is expected according to EC8. the only data to deviate is data for ground D, which showed slightly lowerintensitiesthantheintensitiesongroundC.WealsonoticedasignificantdatadeviationwithingroundD intensities,suggestingamajorinfluenceofotherfactors.Forthegroupofallelevenearthquakesweobtained similarresults.Despitethefactthattheothersixearthquakesslightlylessfulfiltherequirements,weobtained similar results also for them. We conducted also Wilcox rank-sum test (SPSs Inc. 1999), a nonparametric test to determine signif­ icantdifferencesbetweenmeanvaluesforindependentsamples.testshowedsimilarresultsasothertests, that the most distinguished ground from ground type C is ground S1 and the least is ground D. 7 Conclusion Seismic wave amplification contributed to severe damage and loss of life in a number of earthquakes in therecentpast.Itisbecauseofheavydamagetostructures,causedbysiteeffectsonsoftground,thatstud­ies of the effects of the local ground increased so greatly. Since quantitative seismic ground-motion data arenotalwaysavailableforcarryingoutmicroseismicresearch,macroseismicdataareimportantforanaly­sis of earthquake effects. thestudycoveredthegreaterLjubljanaarea,forwhichweestimatedintensitiesbyusing1,296macro­seismicquestionnaires,whichcorrespondto11differentearthquakes.Wedeterminedintensitiesforareas witharadiusnotexceeding5kmwhichwerelocatedonhomogeneousgroundaccordingtoEC8.Weused groundclassificationbasedonEC8derivedfromOGK( upančičetal.2004),butinsomelithologicalunits difficulties in determining the ground types have emerged. this is mainly due to a lack of clarity in EC8 classificationbasedonlithologyandalackofdataonquantitativegeomechanicalproperties.thisapplies especiallyforsedimentsintheLjubljanaMoor(groundtypeS1).Groundwhereobserversresidewasdivid­ed into several polygons and for each polygon we determined seismic intensity. Statisticalanalysiswasdoneforthreeseparategroupsofearthquakes.Foreachgroupweselectedtheref­erence polygon on ground type C, with which we compared the intensity of other polygons for the same earthquake. the results showed an increase in seismic intensities as the quality of the soil deteriorated. OngroundtypeAtherearemorelowintensitiesthanhighcomparedtothegroundC.Intensitiesofearth­quakesongroundCaremoreequallydistributed.GroundtypeEandS1showedmorehighintensitiesthan low compared to the ground type C. Ground S1 has also more high intensities than ground E. results on ground type D deviate from others, since according to EC8, we would expected higher values. this may be due to some unrevealed geological characteristics, like lateral distribution of soft ground, thickness of deposits, influence of topography or just because we have very limited macroseismic data for individual polygonswithingroundD.therefore,itwouldbenecessarytoinvestigatealsootherpropertiesofsoftsed­iments in the future. IngeneralinvestigationsbasedonintensitydatainSloveniaarequitedifficulttoperformbecausethere arenotmanystrongearthquakes. therefore,wehaveto usealso lowerintensitydata,whichare often not as indicative regarding the influence of local ground. the results of this study will contribute to a better assessment of seismic hazard in the greater Ljubljana area, because it is important that methodology of analysing macroseismic data sits side by side with other analyses of site effects. 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SPSs Inc. 1999: SPSs Base 9.0 applications guide. toshinawa, t., taber, J.J., Berill, J.B. 1997: Distribution of ground–motion intensity inferred from ques­tionnairesurvey,earthquakerecordings,andmicrotremormeasurments–acasestudyinChristchurch, New ealand,duringthe1994Arthurspassearhquake.BulletinoftheSeismologicalsocietyofAmerica 87-2. upančič,P.,ŠketMotnikar,B.,Gosar,A.,Prosen,t.2004:KartapotresnemikrorajonizacijeMestneobčine Ljubljana. Potresi v letu 2002. Ljubljana. upančič,P.2013:MikrorajonizacijaobmočijvSlovenijizvečjopotresnonevarnostjo.Potresivletu2012. Ljubljana. Makroseizmične raziskave vplivov lokalne geološke zgradbena intenzitete izbranih potresov na širšem območju Ljubljane DOI: http://dx.doi.org/10.3986/AGS.793 UDK: 550.34(497.451) COBISS: 1.01 I VLEČEK:LjubljanaležinaenemodtrehpotresnonajboljnevarnihobmočijvSloveniji.Polegtegameh­kejšisedimentivLjubljanskikotlinimočnovplivajonapotresnonihanjetal. makroseizmičnimipodatki smoraziskalivplivgeološkepodlagenaintenzitetenekaterihpotresovnaširšemobmočjuLjubljane.Določili smo intenzitete enajstih potresov na homogenih območjih, ki smo jih določili v skladu s klasifikacijo tal poevropskemstandarduEvrokod8(EC8).rezultatisopokazalisistematičnopovečevanjepotresnihinten­zitet,opredeljenihpoEvropskipotresnilestvici(EMS–98),sslabšanjemseizmogeološkihlastnostital.rahlo odstopanje smo zaznali le na tleh vrste D, na katerih imajo potresi nekoliko nižje intenzitete od pričako­vanih.Vzrokselahkoskrivavostalihgeološkihindrugihdejavnikihalizgoljvtem,daimamozaposamezna območja na tleh D zelo malo podatkov. KLJUČNEBESEDE:Evropskapotresnalestvica,intenziteta,makroseizmičneraziskave,Evrokod8,potresna mikrorajonizacija, Ljubljanska kotlina NASLOVI: Anita Jerše Agencija rs za okolje Urad za seizmologijo in geologijo Dunajska 47, SI ) 1000 Ljubljana, Slovenija E-pošta: anita.jerse@gmail.com mag. Mladen Živčić Agencija rs za okolje Urad za seizmologijo in geologijo Dunajska 47, SI ) 1000 Ljubljana, Slovenija E-pošta: mladen.zivcic@gov.si dr. Andrej Gosar Agencija rs za okolje Urad za seizmologijo in geologijo Dunajska 47, SI ) 1000 Ljubljana, Slovenija in Univerza v Ljubljani Naravoslovnotehniška fakulteta Aškerčeva cesta 12, SI ) 1000, Ljubljana, Slovenija E-pošta: andrej.gosar@gov.si 1 Uvod Potresjenaravnipojav,kiganemoremonapovedatiinnadzorovati,lahkopagadobroopišemoskoziana­lizonjegovihučinkov.Makroseizmičnipodatkipodajalosistematičenopisučinkovpotresanaljudi,predmete, zgradbe in naravo. Amplitudanihanjataljeodvisnaodžariščnihlastnostipotresa(magnituda,globina,oddaljenost,žarišč­nimehanizem),odvplivaregionalnegeološkezgradbenaširjenjepotresnegavalovanjainodvplivalokalne geološke zgradbe. Vpliv slednje imenujemo tudi vpliv lokalnih tal. Pri ocenjevanju potresne nevarnosti na mehkih tleh, pospešek nihanja tal na trdni skali v podlagi pomnožimo z ustreznim faktorjem tal. Namen te raziskave je bil oceniti vpliv lokalne geološke zgradbe na intenzitete nekaterih potresov na širšemobmočjuLjubljanenapodlagiklasifikacijetalpoEvrokod8standardu(EC8)(SIStEN1998–1,2005; SIStEN1998–1/A101,2005). apotrebemakroseizmičnihraziskavsmoanaliziralivprašalnike,kijihhra­nimo v arhivu. Pri opredeljevanju intenzitete smo sledili načelom Evropske potresne lestvice (EMS–98) (Grünthal 1998). Intenzitete potresov smo določili za območja, katerih polmer ne presega 5km in ki se nahajajona homogenihtleh gledena EC8. Napodlagi geološkekartevmerilu1:100.000 innjenih tolma­čev smo geološko podlago območja razdelili v pet razredov po EC8. Statistično analizo smo naredili za podatke treh ločenih skupin potresov. Pri vsaki skupini smo izbrali referenčno intenziteto primerjalnega poligona, s katero smo primerjali intenzitete drugih poligonov istega potresa. 2 Dosedanje raziskave vpliva lokalne geološke zgradbe na učinke potresov Ojačitvepotresnegavalovanjavaluvialnihnanosihsoževelikokratprispevalekvečjiškodiinizgubi živ­ljenj, na primer v Christchurchu, 2011 (Bradley 2012) in v Emiliji–romani 2012 (Maugeri s sod. 2013). Naobmočjihzzapletenogeološkosestavosevplivlokalnihtallahkozelospreminja(toshinawaet.al.1997). Posvetujebilonarejenihžekarnekajraziskav,skaterimisonapodlagimakroseizmičnihpodatkoviskali povezavo med intenziteto in geološko podlago. Prve pomembnejše raziskave so bile narejene na Novi elandiji(Elderssod.1991,toshinawassod.1997).tudivItalijijebiloopravljenihvečraziskavoučinkih potresanpr.naobmočjuPalerma(Giammarinarossod.2005)inrima(Cifellissod.2000;Sbarrassod.2012). V Sloveniji smo velike razlike v poškodovanosti stavb opazovali v primeru potresov 1998 in 2004 v Krn­skempogorju. Pretežnosmojihlahkopojasnilizresonančnimiučinkimedtlemiinobjekti(Gosar2007; Gosar 2010). Na podlagi novejših rezultatov so strokovnjaki predlagali (Sbarra s sod. 2012) uporabo makroseizmič­nihrezidualovpriizdelavikartpotresnenevarnosti.Ugotoviliso,danaintenzitetovplivatudispreminjanje tal z globino in debelina posameznih plasti. 3 Geološke značilnosti in klasifikacija tal po EC8 na širšem območju Ljubljane Ljubljana,kijeenoodtrehpotresnonajboljnevarnihobmočijvSloveniji(Lapajnessod. 2001),leživpli ­tvem sedimentnem bazenu zapolnjenim s heterogenimi kvartarnimi nanosi (slika 1), ki imajo različne seizmogeološkelastnosti.razlikujemotriglavnedele:Ljubljanskopolje,Ljubljanskobarjeinobrobnohri ­bovje. Podlago bazena gradijo permski in karbonski skrilavi glinavci, peščenjaki in konglomerati ter mezozojske karbonatne kamnine, ki izdanjajo na robovih hribovja. Ljubljansko polje prekrivajo prodni nanosi reke Save, na Ljubljanskem barju pa sta prod in pesek prekrita z jezerski in barjanski sedimenti. Č (čČ ) Glej angleški del prispevka. V EC8 je vpliv lokalnih tal na učinke potresa predpisan s koeficientom tal s (ang. soi1 factor), ki nam pove, koliko večje pospeške nihanja pričakujemo v primerjavi z referenčno trdno kamnino. EC8 določa sedemtipovtal,kisoopisanisstratigrafskimprofilomintremikvantitativnimiparametri:hitrostjostrižnega valovanjavzgornjih30m(.s,30),zrezultatomstandardnegapenetracijskegapreizkusa(Nspt)instrižnotrdnost­jotal(cu). aposebnatipatalS1inS2koeficienttalnipodaningajetrebadoločitisposebnimiraziskavami. Vpliv krajevne geološke sestave na potresno nihanje tal podaja karta potresne mikrorajonizacije. Na podlagigeološkekarte(OGK100)innjenihtolmačevsmorazširilikartopotresnemikrorajonizacijeMest­ne občine Ljubljana ( upanči s sod. 2004) na širše območje Ljubljane (slika 2). tla so razdeljena v pet razredov: * A ) koeficient 1,00, * C ) koeficient 1,15, * D ) koeficient 1,35, * E ) koeficient 1,70, * S1 ) koeficient 2,55. Č Glej angleški del prispevka. UporabilismoklasifikacijotalpoEC8napodlagiosnovnegeološkekarte( upančičssod.2004),kjer sogeološkoinlitološkozgradboobmočjaLjubljanepovzelipoOGK100,listKranj(GradinFerjančič1974), Ljubljana(Premru1983),Postojna(Buserssod.1967)inribnica(Buser1969).KerjetiskanakartaOGK100 narejena na precej slabi geodetski podlagi, je tudi njena natančnost v digitalni obliki slabša. Na digitalni kartisozatoprivzelinatančnostmej50m. atomoramoupoštevati,damakroseizmičniopazovalci,kise nahajajo blizu meje, morda niso uvrščeni v pravi razred tal po EC8. Jugozahodnidelozemlja(Ljubljanskobarje)spadavtiptalS1,večinavzhodnegaindelzahodnegaozem­ lja spada v tla A, osrednji del v tla C, vmes pa so manjša območja, ki spadajo v tip tal D in E (slika 2). Na širšem območju Ljubljane ni ugotovljenih tal tipa B ali S2. 4 Zbiranje makroseizmičnih podatkov in opredeljevanje intenzitete Oceno učinkov potresa na predmete, ljudi, zgradbe in naravo podaja intenziteta potresa, ki jo določimo spomočjointenzitetnelestvice.Prvikorakjepridobitevvsehopisnihinformacijoučinkihpotresanadolo­čenilokaciji.Podatkenatorazvrstimoponaseljihterjihprimerjamosseznamomdiagnostičnihkriterijev ter določimo kateri opis intenzitetnih stopenj najbolj ustreza podatkom. MakroseizmičnevprašalnikehranimovarhivuUradazaseizmologijoingeologijo.Podatkivključuje­jovprašalnike,kisojihopazovalciposlalipopošti,poelektronskipoštialiprekospletnegaobrazca.Intenzitete smo določali za izbrana območja v Ljubljani, opredeljena s klasifikacijo tal po EC8 in ne po naseljih, kot je običajno. Vsaka ocenjena intenziteta se nanašala na območje, katerega polmer ne presega 5km, in ki se nahajanahomogenih tlehpo EC8,saj je sicerrazponzabeleženih učinkov lahkozelo velik,gledenato da se geotehnične lastnosti tal spreminjajo. Posledično smo tla, kjer prebivajo opazovalci, razdelili na ve poligonov(slika3)invsakemupoligonudoločiliintenzitetopotresa.Določilismo4poligonenatlehtipaS1, 2 na tleh E, 6 na tleh D, 10 na tleh C in 8 poligonov na tleh tipa A. Pri opredeljevanju intenzitete smo sle­dili načelom Evropske potresne lestvice (EMS–98) (Grünthal 1998). čČ Glej angleški del prispevka. 5 Uporabljene metode in analiza podatkov a analizo makroseizmičnih podatkov smo zbrali 17 potresov (preglednica 1), ki so se zgodili med leto ­ ma1998in2005tersobilidovoljmočnizanašnamen. Izteskupinesmonatouporabili11tistih,kisočim bolje izpolnjevali naslednje pogoje: * da so čim bolj oddaljeni od Ljubljane. V tem primeru lahko zanemarimo razlike v nadžariščni razdalji med različnimi deli mesta in tako vidimo razlike v intenzitetah zaradi vpliva geološke podlage; * dapotresnovalovanjeprihajaizpodobnesmeri.Vplivgeološkezgradbenaširjenjepotresnegavalovanja je v tem primeru podoben; * da so dosegli največjo intenziteto najmanj V EMS, na območju Ljubljane pa najmanj IV–V EMS; * da zanje obstoja zadostno število makroseizmičnih podatkov. Pri potresih v okolici Brezovice (2002) in pri Cerknem (2005) je šlo za ve zaporednih sunkov, kate­rihučinkesmoopredeljevaliskupaj,sajjebilopremalopodatkov,kibiomogočilitočnoopredelitevintenzitete vsakega sunka posebej. raziskavo smo opravili za tri skupine potresov. Najprej smo se osredotočili na potrese (pet od njih), ki pogoje najbolje izpolnjujejo. Njihova oddaljenost od Ljubljane je med 45 in 120km. Potresno valova­nje te skupine prihaja iz severozahodne smeri. Druga skupina potresov pogojev ne izpolnjuje tako dobro (šest od njih). Njihova oddaljenost od Ljubljane je manjša in sicer med 10 in 45km, potresno valovanje pa prihaja iz različnih smeri. Ocenjene intenzitete potresov te skupine so malo nižje od tistih v prvi sku­pini.tretjaskupinapredstavljavsehenajstpotresov.Analiziralismo1296vprašalnikovopotresnihučinkih, kijihjeizpolnilo616opazovalcev.ObravnavalismoširšeobmočjeLjubljane,kiseraztezanajugudoŽeli­melj, na severu do trzina, na zahodu do Dragomera in na vzhodu do vasi Volavlje (slika 3). 6 Rezultati in razprava a vsako od treh skupin potresov smo izbrali primerjalni poligon, katerega intenziteta je bila referenčna. njo smo primerjali intenzitete drugih poligonov za vsak potres (preglednica 3). Število vseh ocenjenih intenzitet znaša 224 in so podane v preglednici 2. Vpreglednici jepolegintenzitetev oklepaju podano še številovprašalnikovnapodlagikaterih je bila intenzitetaopredeljena.Intenzitet,kisodoločenelenapodlagienegavprašalnika(označenordeče),nismo uporabili v statistični analizi. V nadaljnji raziskavi smo uporabili 160 intenzitet. Pri razponu intenzitet, npr. IV–V EMS, je bila v izračunih uporabljena vrednost 4,5. a primerjalnega smo izbrali poligon na tleh tipa C, saj imajo tla C srednje vrednosti geomehanskih parametrovgledenaostaletipetal.Vskupinivsehenajstihpotresovsmoizbralitretji(C 3),vskupinipetih potresovdrugega(C 2)invskupiniostalihšestpotresovpetipoligon(C 5).Izbranpoligonvsebujepodat­ke za vse potrese, ne vsebuje podatka, da opazovalec potresa ni čutil, in ima približne srednje vrednosti intenzitetvprimerjavizostalimipoligoninatlehC.PoligonaC 4nismoizbralizaprimerjalnega,kernje­gove vrednosti nekoliko odstopajo od povprečnih. avsakpoligonsmoizračunaliodstopanjeodreferenčneintenzitetezavsakpotresposebejtervečsrednjih vrednosti odstopanj od referenčne intenzitete, in sicer: aritmetično sredino, mediano, modus in modifi­ciranomediano,prikaterismopredpostavili,dajepodatek»ničutil«najmanjši.Priizračunuaritmetične sredine pa podatka nismo upoštevali, če opazovalci potresa niso čutili. Najprej smo opravili statistično analizo vsakega posameznega poligona (preglednica 3) in nato še za združene poligone glede na tip tal po EC8 (preglednica 4). rezultati na podlagi petih potresov kažejo, da odstopanja od referenčne intenzitete naraščajo s slab­šanjem lastnosti tal (predvsem na tleh tipa E). Vendar pa rezultati tipa tal D odstopajo od ostalih, saj bi glede na koeficient tal po EC8 pričakovali višje vrednosti od tistih na tleh C in ne manjše. Verjetno tičijo vzroki v neodkritih geoloških in ostalih dejavnikih. rezultati na podlagi vseh enajstih potresov kažejo podoben trend naraščanja vrednosti odstopanj od referenčne intenzitete kot pri rezultatih analize petih potresov. Na tleh D dobimo višjo aritmetično sre­dino od tiste na tleh C, nasprotno pa je modus negativen. V preglednici 5 podajamo, kolikokrat je bila intenziteta manjša, večja ali enaka referenčni intenziteti natlehC,kisobilaprivzetazaprimerjalnatla.Modrabarvaoznačujeintenzitete,kiprevladujejonaposa­meznih tleh. Vskupinipetihpotresovjevidnopoviševanjeintenzitetsslabšanjemtal.NatiputalAimamoopredeljenih ve nižjih intenzitet kot višjih. tla C imajo precej enakomerno razporejene intenzitete, kar je pričakova ­ no,gledenato,dasmotatlaizbralizaprimerjalna.tlaEimajovečvišjihintenzitetkotnižjihinpravtako tudi tla S1. tla S1 imajo tudi ve višjih intenzitet kot tla E, kar je pričakovano po EC8. Edini podatki, ki odstopajo, so tisti za tla D, saj so intenzitete na teh tleh nekoliko nižje od intenzitet na tleh C. Opazili pa smo veliko odstopanje intenzitet znotraj tal D, kar nakazuje velik vpliv drugih dejavnikov. V preglednici čČ ()() čČ () () Č čČ čČ | vprašalniki o petih potresih 531 | vprašalnik o enajstih potresih 1296 | o vseh potresih 1849 () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () C_3 primerjalni III–IE (3) E (3) IID (6) E (7) IE (6) IV–E (8) IE (3) E (4) IE (4) IE (2) IE (10) poligon ()() () () () () ()() () () () () () () () ()() () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () ()() () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () () ()() () () ()() () () () () Č č() () () Č Č ( ) ( ) ( ) Č ( ) ( ) ( ) () () () () () () Č () () () () () () () () Č Č ( ) ( ) ( ) Č () () () () () () Č () () () () () intenzitetvsehenajstihpotresovsmodobilipodobnerezultate.Kljubtemu,daostalihšestpotresovneko ­liko slabše izpolnjuje pogoje, smo tudi pri njih dobili podobne rezultate. Opravili smo tudi Wilcoxov rank–sum test (SPSs Inc. 1999), to je neparametričen test, da bi določili značilne razlike med srednjimi vrednostmi neodvisnih vzorcev. Pokazal je podobne rezultate kot drugi testi in sicer, da se od tal C najbolj razlikujejo tla S1 in najmanj tla D. 7 Sklep Ojačitvepotresnegavalovanjasovpreteklostipogostoprispevalekvečjiškodiinizgubiživljenjobpotre ­sih. Prav zaradi težkih poškodb objektov, povzročenih z lokalnimi učinki, so se študije vplivov mehkih sedimentovzelopovečale.Kerkvantitativnipodatkigibanjatalnisovednonavoljozaizvedbomikroseiz­mičnih raziskav, je pomembna analiza makroseizmičnih podatkov o učinkih potresa. raziskavesozajeleširšeobmočjeLjubljane,zakateregasmoopredeliliintenzitetezuporabo1296ma­kroseizmičnihvprašalnikov,kisosenanašalina11različnihpotresov.Intenzitetesmodoločaliza območja katerih polmer ni presegel 5km in ki ležijo na homogenih tleh po EC8. tla smo klasificirali po EC8 na podlagiOGK( upančičssod.2004),vendarsejeprinekaterihlitološkihenotahpojaviladilemapridolo­čanjutipatal.VzrokjepredvsemvnedorečenostipriklasificiranjutalpoEC8gledenaopislitološkesestave inpomanjkanjukvantitativnihpodatkovogeomehanskihlastnostih.toveljapredvsemzasedimenteLjub­ljanskegabarja(tiptalS1). Območjesmonatoznotrajistegatipatalrazdelilinavečpoligonovinvsakemu poligonu določili intenziteto potresa. Statističneanalizesmoopravilinatrehrazličnihskupinahpotresov. avsakoskupinosmoizbralirefe­renčni poligon na tipu tal C. rezultati so pokazali povišanje intenzitete potresov na slabših tleh. Na tipu talAjebiloopredeljenihvečnižjihintenzitetkotvišjihvprimerjavistlemiC.IntenzitetepotresovnatlehC so enakomerno razporejene. tla E in S1 imajo ve višjih intenzitet kot nižjih v primerjavi s tlemi tipa C. tla S1 pa imajo tudi ve višjih intenzitet kot tla E. Na tipu tal D se pojavi odstopanje rezultatov, saj bi po EC8pričakovalivišjevrednosti.Mordatičijovzrokivostalihneodkritihgeološkihdejavnikih,kotsolateral­narazširjenostmehkihzemljin,debelinananosov,vplivtopografijealipazgoljvtem,daimamozaposamezne poligonenatlehDzelomalopodatkov.Vprihodnjebibilotorejdobroraziskatitudidrugelastnostimeh­kih sedimentov. raziskavenapodlagipodatkovointenzitetahjevSlovenijidokajtežkoopravljati,sajnivelikomočnih potresov. ato se moramo zadovoljiti s podatki o nižjih intenzitetah, ki pa pogosto niso tako indikativni gledevplivalokalnihtal.rezultatiteštudijeprispevajokboljšiocenipotresnenevarnostinaširšemobmočju Ljubljane, saj je pomembno, da metodologijo analize makroseizmičnihpodatkov postavimoob bok dru­gim metodam analize lokalnih učinkov potresov. AHVALA: Avtorji se zahvaljujejo Ini Ceci za pomo v zvezi z makroseizmičnimi podatki. Anita Jerše sezahvaljujetudiPoloni upančičzavsopomočpriuporabigeografskegainformacijskegasistema(GIS). 8 Literatura Glej angleški del prispevka. theterracedlandscape inthebrkinihills terasiranapokrajina v brkinih Lučka Ažman Momirski, Drago Kladnik Č The terraced landscape in the Brkini Hills DOI: http://dx.doi.org/10.3986/AGS.1627 UDC: 911.53:631.613(497.47) COBISS: 1.01 ABStrACt:thestudyofterracedlandscapesisbecominganincreasinglyimportantareaofinternational research. this paper starts by presenting the most important research and professional activities related toterracedlandscapesandexamplesofstudyingthemaroundtheglobe.thisisfollowedbyadetailedpre­sentationofthefeaturesoftheuniqueterracedlandscapeintheBrkiniHills,Slovenia.Foramoredetailed analysis,fivevillageswereselectedinthecentralandwesternpartoftheregion.Interdisciplinaryresearch includes studying extremely unfavorable demographic processes, natural factors at work in the modern terraced landscape,historicalchangesinlandscapephenomena, andadetailed observation oftheterrace forms thatcomprise theterraced landscape. Despitemodern mechanizedfarming, the remainingfarmers arefindingitincreasinglydifficulttomaintaintheterracedlandscape,whichisalsothreatenedbyafforesta­tion. the mixture of very long terrace platforms and the distinct intermediate slopes presents a unique experiential value that is increasingly being lost. KE WOrDS:ruralgeography,culturallandscape,landuse,terracedlandscape,cultivatedterraces,Brkini Hills, Slovenia the article was submitted for publication on January 26, 2015. ADDrESSES: Lučka Ažman Momirski, Ph.D. Faculty of Architecture University of Ljubljana oisova cesta 12, SI ) 1000 Ljubljana, Slovenia E-mail: lucija.azman@fa.uni-lj.si Drago Kladnik, Ph.D. Anton Melik Geographical Institute research Center of the Slovenian Academy of Sciences and Arts Gosposka ulica 13, SI ) Ljubljana, Slovenia E-mail: drago.kladnik@zrc-sazu.si 1 Introduction the study of terraced landscapes intensified at the close of the twentieth century. In 1997, Cinque terre, a belt on the northeastern coast of the Ligurian Sea in Italy, was added to the UNESCO World Heritage List(underthe new »cultural landscape( category; Albertiand Lodatti 2012). this steep cliffcoastisalso an exceptionally picturesque terraced area. the significance of areas »whose character is the result of the action and interaction of natural and/or human factors( (Internet 1, Article 1 of the General Provisions) was also highlighted by the adoption of the European Landscape Convention. Between 2001 and 2010, several international projects on safeguarding, restoring, and planning ter­raced landscapes were carried out, including the following: * PAttEr: the purpose of this project was to identify and describe the types and condition of cultivated terracesontheSpanishislandofMajorca,andintheareassurroundingNiceandGenoa(Lasantaetal.2013); * PrOtErrA: this project supported twelve pilot actions aimed at restoring cultivated terraces in six Mediterranean countries (Internet 2); * ALPtEr:themaingoalofthisprojectwastoimproveawarenessofthespatialfeaturesofterracedland­scapes in the Alpine region (Internet 3); and * tErrISC:thisprojectexploresthepreservationofterracedlandscapesasastrategyforpreventingnat­uraldisasters,especiallyfloodsanderosion,intheBalearicandCanaryIslands,Portugal,andsouthwest France (Internet 4). theEUincludedcultivatedterracedlandscapesinits2007–2013ruraldevelopmentplan,itsBiodiversity Action Plan for Agriculture (to improveor maintain biodiversity and prevent its decrease dueto agricul­tural activities), and its Soil thematic Strategy. the EU also supports areas with limited development opportunities and agricultural areas with highly ranked natural values, which in many cases include ter­racedland. thepreservation andmaintenance ofterraced landscapes arealsoamong thepriorities ofthe Soil thematic Strategy (Lasanta et al. 2013). the international study of terraced landscapes reached its peak with the first two international con­ferencesonterracedlandscapes.Atthefirstone,whichtookplaceinChinainthefallof2010,theInternational terracedLandscapesAlliance(ItLA)wasestablishedandtheHongheDeclarationontheprotectionand developmentofterraces(Internet5)wasadopted.togetherwithoverahundredconferencepapersonvar­ious aspects of terraced landscapes from around the globe, this declaration is also published in extensive volumes in Chinese and English (Peters and Junchao 2012). Not many regional studies of terraced land­scapeswerepresentedattheconference.Inadditiontoafairlyinsufficientpresentationoftheglobaldistribution ofterracedlandscapes(rivera2012)andtheALPtErprojectresultsintheVenetoregion(AlbertiandLodatti 2012), the noteworthy contributions are on efforts to protecting the traditional terraced landscape in the southernChineseprovinceof unnan(Wenxing,KunandLingchong2012)andeffortstoprotectanddevel­op terraced areas in the Philippine Cordilleras (Baguilat 2012). Ann Kendall’s article (2012) presents in detailthestudy ofextensificationof cultivatedterracesin theAlpujarraValleyonthesouthernrimsof the Sierra Nevadas (Douglas, Critchley and Park 1996) and compares them to the Inca terraces in Peru. the second ItLA conference was held in Peru in the spring of 2014. It began with the presentation of animportantChineseachievement:in2013,theculturallandscapeoftheHaniriceterracesinHonghePrefecture intheprovinceof unnanwaslistedasaWorldHeritageSite(Junchao2014).theextensivestudyofeleven terraced landscapes in Peru took into account both active and abandoned terraces (Lambruschini 2014), andespeciallyinterestingwasthecomparisonofthefeaturesandissuesofterracedlandscapesinPeruand Japan(Baba2014).therestorationofBolivianterraceswaspresentedindetailusingthecaseofthesettlements in tapacara Province in the Cochabamba Department (Crespo 2014). there were a few presentations of Europeanterracedlandscapes;noteworthyamongthemweretheeffortstopreservetheterracedlandscape in the Cembra Valley north of trento in the trentino–Alto Adige region in Italy ( anotelli 2014). Withtheexpansionoftheresearcharea,thepublicationofresearchfindingsalsointensified.theresults of the ALPtEr project had already been presented in two publications: Terraced LandscapeA of the Alps: AtlaA (ScaramelliniandVarotto2008)and TerracedLandscapesoftheAlps:ProjectsinProgresA (Fontanari andPatassini2008).thefirstpublicationalsoincludesseveralsynthesesofresultsofregionalstudiescon­ducted as part of this project (Castex et al. 2008; Brancucci and Comenale Pinto 2008; Freppaz et al. 2008; Mazzolenietal.2008;Werderetal.2008;CheminandVarotto2008;AžmanMomirski2008;Arnberger,Eder andBrandenburg2008).WithregardtotheALPtErproject,onealsoneedstomentiontheinterdisciplinary volumeontheterracedlandscapeoftheGoriziaHills(AžmanMomirskietal. 2008),whichalsoincludes studies on land use changes and landslide hazard. this publication is definitely the most comprehensive Slovenian presentation of this topic to date. An exhaustive chronological overview of research on cultivated terraces and terraced landscapes in Slovenia, and an outline of Slovenian terraced landscapes were only published a few years ago (Ažman Momirski and Kladnik 2009). Considering that in many parts of Slovenia cultivated terraces have fairly strongly(andinsomeplacesevenpredominantly)characterizedthelandscape,onewouldrightfullyexpect thatmuchmoreresearchhasbeendoneinthisarea.thecurrencyofthisresearchtopicwasdefinitelythe impetusfortwograduate-levelstudiesbyHelenaKrižajSmrdel(2010a;2010b).Continuednationalresearch on Slovenian terraced landscapes provided the motivation for a volume on terraced landscapes in sub-Mediterranean Slovenia (Ažman Momirski 2014). the traditional terraced landscape of the Brkini Hills is unique in both Slovenia and beyond, and it therefore deserves more detailed treatment. It has been studied relatively poorly to date. Perhaps the most directtreatmentsofarhasbeenprovidedbyacomparativestudyofthelandusechangesintheMediterranean terracedsettlementsofKrkavčeintheKoperHillsandOstrožnoBrdointheBrkiniHills(AžmanMomirski andGabrovec2014);OstrožnoBrdoisalsooneofthefivesamplesettlementsinthisstudy.Itwasalsostud­ied as a pilot area by Križaj Smrdel (2010a; 2010b). It is interesting that in his detailed demographic and economic study of the region between Mount Snežnik and Mount Slavnik, in which he also describes in detail theconditions inthe BrkiniHills,therecognized Sloveniansocial geographerVladimir Klemenči wasbarelyawareofcultivatedterracesandterracesasimportantlandscapeelementsbecausehementions them only fleetingly in two places (Klemenči 1959). 1.1 Outline of the study area Slovenia is among the few places in Europe with cultivated terraces throughout the entire country. they appearinalltypes ofSlovenianlandscapes, butdifferby frequency,purpose,and contemporary function (Ažman Momirski and Kladnik 2009). Notmany countries can compare toSlovenia in termsoflandscapediversity;it is locatedat theinter­section of the Alps, the Pannonian Plain, the Dinaric Alps, and the Mediterranean, and is influenced by theGermanic,Hungarian,Slavic,andromancecultures.Itisknownforbothitsnaturalandculturaldiver­sity, as well asits variability and transitional character. One can distinguish between four basic landscape types and nine subtypes (Kladnik, Perko and Urbanc 2009). One of the basic Slovenian landscape types is theMediterraneanlandscape,whichisdividedintotwosubtypes:MediterraneanlowhillsandMediterranean plateaus(Perko1998).Mediterraneanhillsarecharacterizedbyapoorlypermeableflyschsubstratum,and Mediterraneanplateausarecharacterizedbyapermeablelimestonesubstratum,ofwhichdiversekarstfea­tures are typical. the majority of terraces that define the most typical terraced landscapes can be found in the Mediterranean region, but many can also be found in karst Dinaric landscapes and the winegrow­ing Pannonian low hills (Ažman Momirski and Kladnik 2009). they are rarer elsewhere, but only a few Slovenianlandscapeslackthemcompletely. Amongtheninenaturalsubtypes,onlythePannonianplains are completely without any terraces. the Brkini Hills are classified under Mediterranean low hills, but their characteristics make them sig­nificantlydifferentfromtypicalMediterraneanlowhills(e.g.,theGorica,Koper,andVipavaHills,andeven theflyschVipavaValley);becauseof theirhigherelevation(theirhighestpoint,817mabovesealevel,isat Saint Servulus’ Church above Artviže), they are more like hills, and because of their location towards the interiorofSloveniatheycombinethefeaturesoftheMediterraneanandcontinentalclimates(Ogrin1996). the mesoregion of the Brkini Hills and reka Valley has a diverse landscape composition and runs in anorthwest-southeastDinaricdirectioninsouthwestSlovenia(Figure1).Ithasanareaof341.5km2,which accounts for 1.68% of Slovenia’s total area. the region is divided between the municipalities of Divača, Hrpelje -Kozina,IlirskaBistrica,andPivka,andalsoincludestherekaValleyinadditiontotheBrkiniHills. the reka Valley is divided into the Podgora area, the Ilirska Bistrica Basin, the gorge section of the valley, andtheVremeValley;inaddition,theKošanaValleynorthoftherekaValleyisalsopartofthemesoregion. p the BrkiniHillsare predominantly composedof impermeableEoceneflysch andcanbe divided intothe western,central,andeasternparts.thereisanotherareaoflesspronouncedflyschhillsbeyondtheJelšane lowland to the southeast, which can be referred to as the Jelšane Hills (Šebenik and Kladnik 1998). the majority of terraces ) which can be classified as agricultural under the basic typology (Ažman Momirski andKladnik 2009) –canbe foundinthe centraland western partsof theBrkiniHills. therefore,fiveset­tlementswereselectedinthisareaformoredetailedstudy:ArtvižeintheMunicipalityofHrpelje -Kozina, Ostrovica, Vatovlje, and Kozjane in the Municipality of Divača, and Ostrožno Brdo in the Municipality of Ilirska Bistrica. the selected settlements in the northwestern part of the mesoregion border on one another, and the total areatheycover runsinaneast-westdirectionandmeasures2,201.9ha or 6.4%oftheentiremesore­gion. the average elevation of the mesoregion is 562m, but the average elevation of the area studied is nearly 635m. Compared tothe rest of themesoregion,it includesmore land with anorthern and eastern aspect,butevenmoreobviousisitsgreaterinclination:itspredominantslopegradientrangesfrom30.1% to 50% (16.8č to 26.6°; 44.5% of the area), whereas the inclination in the rest of the region predominant­ly ranges from 15.1% to 30% (8.6č to 16.7°; 32.4% of the region). In the entire mesoregion, 30.9% of land has a slope gradient below 15% (below 8.5°), whereas in the pilot area this percentage is only 10.6%. the Brkini Hills and the reka Valley have a 71.4 percent share of forest, which ranks them among extremely wooded Slovenian mesoregions. the study area is even more wooded than that (81.4%); meadows and pasturespredominateamongagriculturalareasandtilledlandaccountsforlessthanonepercent(0.83%). thestudyareaofthefivesettlementsliesinŠkocjanCavesregionalPark,whichcovers450km2andincludes theentirerekawatershed(Internet6).thefivesettlementsstudiedalsopartlyextendintowaterprotection zones. the southern part of Ostrožno Brdo extends into a natural asset area (the Šmagurka Creek Valley), anditsnorthernpartalongtherekariverbelongstoimportantecologicalareasorspecialconservationareas. the sample settlements selected vary by location. Ostrožno Brdo and Kozjane are located at the top oftheridge,Artviželiesslightlybelowthetop,andOstrovicaandVatovljelieontheslopes.OstrožnoBrdo and Kozjane are ribbon villages and the other three are clustered villages. () All of the settlements are away from main traffic routes and major employment centers. In addition, theirdramaticdemographicdevelopmenthasbeeninfluencedbytheirlocationattheedgesoftheirrespec­tive municipalities. In 2011, all five settlements had a total population of 191, which is only 16.8% of the population they had during the peak year of 1890, when 1,140 people lived in the area. the population began to rapidly and inexorably decrease after the Second World War, even though it had already been decreasing persistently during the first half of the twentieth century. Ostrožno Brdo is the largest among the five; in 2011, it had a population of 94, and a full 433 in 1890. Kozjane is now the smallest settlement in terms of population (13 people lived there in 2011), even though its population in 1880 was 283; this wastwiceasmuchasinOstrovicaandVatovlje,whicharenowaheadofKozjanebyafewinhabitants(Ostrovica has a population of 17 and Vatovlje a population of 20). Compared to its maximum population in 1880, thepopulationinKozjanedecreasedto4.6%;Artvižeseemstohavefaredbest,withapopulationof28.0% compared to the peak year of 1880. thepopulationoftheentiremesoregionoftheBrkiniHillsandrekaValleyis15,086.theshareofpop­ulation of the five sample settlements in the entire mesoregion is 1.3%, and the share of population of the mesoregioninSloveniais0.7%.Inthemesoregionasawhole,thepopulationhasalsobeengraduallydecreas­ingeversincethepeakyearof1910,whereasthepopulationintherestofSloveniaischaracterizedbygradual growth across all time periods (Figure 2). thedemographicprofileoftheBrkiniHillsandespeciallythesample settlements isaffectednot only by the extensive decrease in the population, but also the closely related unfavorable age structure, char­acterizedbyapredominanceoftheelderlyandonlyasmallnumberofyoungpeople.theshareoffarming populationhasalsodecreasedbecausepeoplefoundjobsinthevalley.Despitethewidespreaduseofagri­culturalmachinery,theremainingfarmersfinditdifficulttomanageandmaintaintheavailablefarmland andsubsequentlyalsothecultivatedterraces;accordingly,anincreasingnumberoftheseterracesareaban­doned and gradually becoming overgrown with bushes and trees. 1.2 Theoretical premises Withthenewculturalgeography,thestudyoflandscapesshouldextendbeyondmeremorphologicalanaly­sisandbecomeinterpretativeinnature.Attentionisdirectedtowardsmetaphorical,ideological,value-related, and other intangible qualities of landscapes. According to this perspective, the world cannot be compre­hended merely through objective approaches, but can be experienced and understood even more deeply by usinga subjective approach. the»landscape( refers not only tophysical reality and hence, primarilyto space, but also to the organization and perception of the social, cultural, cognitive, political, and econom­icelementsofhumanexistence.thusalandscapeisalsoamentalmapandimage,inwhichonecanidentify diverse stories connected with people’s past and their everyday lives (Urbanc 2008). InSloveniangeography,theevaluationoflandscapeshasbeentackledmostseriouslybyBojanErhartič. In addition to the intrinsic or existential, cultural, socioeconomic, functional, geosystemic, and research andeducationaltypesoflandscapevalues,healsoidentifiedaestheticvalues,whichprovideuniqueexpe­riences.Humanperceptionappreciatesdiversity,complexity,typicalpatterns,andalocalcharacter.Healso mentionsattraction value,inwhich thepresenceof aspecific phenomenonimproves thequalityof lifein a non-material sense and provides an important ace in the hole for tourism (Erharti 2012). theaestheticvalueofterracedlandscapes,includingtheoneintheBrkiniHills,isdefinedbyarepeat­ingpatternofterraceplatformsandslopes,orslopegeometrization.terracedlandscapesarespatialfeatures withexceptionalphysiognomy,inwhichterracesarethemostimportantelementoftheculturallandscape. these types of landscapes are attractive not only during the time of year when the lush and colorful veg­etationseducethelocalsandpassersby,butalsointhewinter,whenthegeometryoftheterracesbecomes evenmorepronouncedinthelandscape(AžmanMomirskiandradikon2008).Duetotheirtypicalland­form, there are frequent attempts to typify terraces that influence the landscape aesthetics. the land use typologyofterraces(AžmanMomirskiandKladnik2009)iswidelyacceptedandused,butsomeauthors alsotypifyterracesbygeographicalarea.Suchtypologicalapproachesmaybeinappropriatebecauseterrace typescanalsooccuroutsideadefinedgeographicalarea. Duetotheiruniqueness,KrižajSmrdel(2010b) defined the terraces in the Brkini Hills as a Brkini type of cultivated terraces or as one of the three types oftraditionalterracesinSlovenia.theexceptionalityoftheBrkiniHillsterracedlandscapeliesintheclear-lyidentifiablecultivatedterracesacrossanextensiveareathataccountforthemajorityoffarmlandaround thelargelyelongatedsettlementsalongtheridges.Eventhoughthelanduseonthemhasextensifiedand partsofthemarealreadybecomingovergrownwithbushesandtrees,themajorityarestillusedandprop­erlymaintained. Acombinationofusuallyverylong,mostlygrass-coveredterraceplatformsadaptedtotheterrain, andpronouncedintermediateslopes,whicharereinforcedwithfruittreesinplaces,offersauniqueexpe­rientialvalue,whichisbecomingincreasinglyevidentwhencomparingthislandscapetootherattractive landscapesinSloveniaandabroad.Itisprobablynocoincidencethatterracedlandscapesareofteninclud-edinthevariousslideshowsofexceptionallybeautifulandpicturesquelandscapesavailableontheInternet (e.g.,Internet7).Infact,oneofthemostfrequentlyusedphotofromSloveniaistheaerialphotoofthe BrkiniHillsslopewithOstrožnoBrdotakenbyMarjanGarbajs.thankstoitsaestheticvalue,ithasbeen publishedinseveralvolumes(e.g.,PerkoandOroženAdamič1998;Lutharetal.2008;KrižajSmrdel2010a) andscholarlypaperswithillustrations(e.g.,Kladnik,PerkoandUrbanc2009). 1.3 Methodology theALPtErprojectteam,foundedin2003and2004basedonuniversityinitiatives,developedthemethod­ologicalbasesforevaluatingterracedlandscapes.thebasesenvisageadescriptionoftheselectedstudy areaandapresentationofitsgeologicalconditions,climate,historicaldevelopment,landuse,terracechar­acteristics,drainage,accessibility,ownership,landprotection,terraceconservationstatus,anddevelopmental factors.Terraced landscapeA of theAlps:AtlaA (ScaramelliniandVarotto2008)containsseveralarticleson thetheoreticalandmethodologicalbasesandthemethodologyofmeasuringandevaluatingterracedland­scapes(e.g.,Scaramellini2008;Acovitsióti-Hameau2008;Bonardi2008;BrancucciandMasetti2008);the article»MappingandGeographicalClassificationofterracedLandscapes:problemsandproposals«(Varotto andFerrarese2008)isespeciallyvaluablefromthemethodologicalpointofview. Digitalorthophotomaps(acolororthophotowithapixelresolutionof0.50m),adigitalelevationmodel (DEM),andtheregisterofthecurrentuseofagriculturalandforestland(Internet8)wereusedtopro­ducemaps.Dataobtainedthroughdeskworkweresupplementedthroughfieldresearchandmapping.the 5×5mdigitalelevationmodelused(DMV5)wascreatedin2011inparallelwiththecyclicalrecording anddesignoftheorthophoto.theregisterofthecurrentuseofagriculturalandforestlandiskeptbythe MinistryofAgricultureandEnvironmentforallofSlovenia.Aninterpretationalkeyisusedfordetermining thecurrentuse,whichincludesvariousdefinitionsoftheavailabledata. thedataonthecurrentusearecapturedusingacomputer-supportedinterpretationoforthophotos andsupplementedwithdatafromotherregisters,fieldresearch,andmeasurements.theregisterofcur­rentlandusedefinesagriculturallandasanylandwithcultivationpotentialthatisnotdefinedasforest. Minimumareasofdatacapturearespecifiedfortheindividualtypesoflanduse(Internet8).thefollowing fivebasiclandcategoriescanbefoundontheterracesintheBrkiniHills:tilledlandandgardens,orchards, grassland,forest,andbuilt-upareas. Eventhoughthelocalnamesofterracesandtheircomponentsareaninterestingresearchtopic,this studyusesthegenerallyknowntechnicalterms.Aterraceiscomposedoftwobasicelements:theterrace platformandtheterraceslope(AžmanMomirskietal.2008).theterraceplatformistheflatpartofthe terrace,wherecropsareusuallygrown,andtheterraceslopeisthesteeperpartconnectingtwoplatforms. terraceslopesmaybecoveredwithsoilandgrassedover,andintheMediterraneanregiontheyareoften madefromstackedrocksthatwereclearedfromthefields. 2 Results theclaimsthatalltheridgesintheBrkiniHillshavebeenconvertedintocultivatedterraces(KrižajSmrdel 2010a,25)arenottrue.theridgeshavebeenconvertedintoterracesonlyinpart;afarmoretypicalspa­tialfeatureintheBrkiniHillsistheterracedupperpartsoftheslopesbelowtheridges(Figure3).thestudy areaincludes228haor10%ofterracedland. p 36