a scientific network for earthquake, landslide and flood hazard...

A Scientific Network for Earthquake, Landslide and Flood Hazard Prevention –SciNet NatHazPrev

OvidiusUniversityofConstantaFaculty ofNaturalandAgriculturalSciences

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Landslide Susceptibility, Hazard and Risk Assessment in Romania – The State of the Art

Zoia Prefac

Presentation content

• Legislativeandinstitutionalframeworkforemergenciesandriskmanagement,

• Susceptibilityandhazardmapping• BibliographyandprojectscontributingtolandslidesusceptibilityandhazardmappinginRomania

• Qualitativeandquatitativeresultsonlandslidessusceptibility/hazardmapping


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Lawsregardingnaturaldisaster– withspecialfocusonlandslidehazardLow/GovernmentalDecision

(G.D.)/CommonorderofMinistry(C.O.)

Overview

G.D. No. 438 /06 June 1996

Regulation of organization and functioning of theCentral Commission for Defense against landslidesand earthquake effects, established by the Minister ofPublic Works and Planning (now the Ministry ofTransport)

C.O. of the Ministry of Public Works andTerritorial Planning, of the Chief ofDepartment for Local PublicAdministration and Ministry of Watersand Environmental Protection No. 62/N‐19.0/288‐1.955/1998

delimitation of the areas prone to natural risks

LawNo.575/22.October2001

• the Plan for national territory development• the maps and tables attached to the Law are providinginformation about the localities potential affected byfloods caused by torrents draining or water coursesoverflowing and landslides.


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In Romania, the lack of a strong legislation at the beginning of thetransition period led to accelerating of the deterioration ofenvironmental conditions and an increase of impact of naturalhazards on society caused by massive deforestation and destructionof irrigation systems in the plains and tablelands (Bălteanu et al.,2004).

Nowadays, Romania has a well‐defined legal framework,covering the requirements for protection against natural disasters,according to those at the European level.

International conventions and other ratified accords andagreements are components of Romanian legislative system and arepart of the national policy for disaster risk reduction management.


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Though, in the implementation of the strategy for civilprotection and environmental safety are leaking.

For example, the Law no. 575 of 22 October 2001, regarding theapproval of the Plan for national territory development – The FifthSection– Areas of natural hazards, foresees risk maps for everylocality placed in the natural risk areas, order to be included inthe Plans for General Urbanism (PUG).

They are managed by local authorities and because of lack offunds, integrated risks maps are not finished, but are underdevelopment.


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Low/GovernmentalDecision(G.D.)/CommonorderofMinistry

(C.O.)Overview

G.D.No.382/2April2003

approves methodological norms regardingminimal demanding in content for territoryplanning and urbanism documentation fornatural risk areas.

G.D. No. 447/10 April 2003 norms regarding elaboration mode and contentof the floods and landslides risk maps

G.D. No. 1 491/9 September 2004

approves the framework regulation of theorganizational structure, responsibilities,operation and endowment of the committees andemergency operational centers

C.O. of the Ministry of Public Minister ofTransport, Construction and Tourism andthe Ministry of Administration and InteriorNo. 1.995/2005/1.160/2006

the Regulation on the prevention andmanagement of specific emergency situationsregarding earthquake and/or landslides risks

G.D. No. 932/7August 2007approves theMethodology regarding state budgetfinancing of natural hazard maps forearthquakes and landslides


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Institutionsandoperationalstructures

FromTheStructure,RoleandMandateofCivilProtectioninDisasterRiskReductionforSouthEasternEurope


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In the literature the terms of susceptibility and landslidehazard are often used as synonyms, although they are differentconcepts (Guzzetti, 2005). Landslides susceptibility is the probability that a landslide tooccur in an area characterized by certain environmentalconditions (Brabb, 1984). Is the degree which a surface can beaffected by the landslide process. In contrast, landslide hazard is the probability that alandslide of a given magnitude will occur in a given period of timeand in a given area. In addition to prediction of where thelandslide will occur, landslide hazard forecast "when" or "howfrequently" it will produce and "how large" it will be (Guzzetti etal., 2005). Thus, susceptibility is the space component of landslidehazard.

Methodsforlandslidesusceptibilityevaluation

Methodsforlandslidesusceptibilityevaluation

QualitativemethodsQualitativemethods

‐ Geomorphologicalmapping;‐ Directmappingmethod;‐Multi‐classweightingmethod;‐ Spatialmulti‐criteriaanalysis;‐ Analyticalhierarchyprocess;‐ Fuzzylogicapproach

‐ Geomorphologicalmapping;‐ Directmappingmethod;‐Multi‐classweightingmethod;‐ Spatialmulti‐criteriaanalysis;‐ Analyticalhierarchyprocess;‐ Fuzzylogicapproach

Quantitativemethods

Quantitativemethods

StatisticalmethodsStatisticalmethods

Bivariate methods:‐Weightsofevidence;‐ Certaintyfactors;‐ Dempster‐Shafermethod;‐ Fuzzylogic.

Bivariate methods:‐Weightsofevidence;‐ Certaintyfactors;‐ Dempster‐Shafermethod;‐ Fuzzylogic.

Multivariatemethods:‐ Discriminantanalysis;‐ Logisticregressionanalysis;‐ Multipleregressionanalysis.

Multivariatemethods:‐ Discriminantanalysis;‐ Logisticregressionanalysis;‐ Multipleregressionanalysis.

Deterministicmethods

Deterministicmethods

‐ Staticinfiniteslopemodeling;‐ Dynamicinfiniteslopemodelingwithrainfalltrigger;‐ Earthquakeinducedinfiniteslopemodeling.

‐ Staticinfiniteslopemodeling;‐ Dynamicinfiniteslopemodelingwithrainfalltrigger;‐ Earthquakeinducedinfiniteslopemodeling.


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In Romania, landslides are among the most widespreadgeomorphological processes in the hilly regions built of Neogenemolasse deposits, as well as in the mountainous regionsdeveloped on Cretaceous and Paleogene flysch.

A review of geomorphic literature regarding landslidesemphasizes that numerous articles and books addressed thissubject, with the aim of classifying, presenting some local cases,or zoning landslides across geomorphic units or all over thecountry, have started especially since the late ’20s (e.g.,Mihăilescu, 1926, 1939; Tufescu, 1964, 1966).

In the recent decades, an issue approached by Ielenicz, 1970;Ichim, 1979; Mac; 1986 and Surdeanu, 1987, was that ofdetection of areas prone to landslides on the principle offunctional analysis of slopes.


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Recent studies in the direction of landslide risk analysis andvulnerability have had: Cioacă et al., 1993, Rădoane et al., 1993,Cioacă, 1996, Surdeanu, 1998, Bălteanu et al., 1989, 2004, 2010,Grecu, 1996, 1997, 2002, Manea, 1998, Armaş et al., 2003,Armaş, 2006, Sandu & Bălteanu, 2005, Prefac et al., 2008.

During the ’90s and early 2000s, in the estimation of landslidesusceptibility was used especially qualitative approaches.

The number of quantitative ones has risen steeply in the lastyears (Micu & Bălteanu, 2009; Armaș, 2011, 2012; Constantin etal., 2011; Șandric et al., 2011; Grozavu et al., 2012; Armaș et al.,2013).


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For Romania, over the time, regarding landslide phenomenon,the spatial distribution of landslides especially, a few mapswere drawn up, at a small scale:

Map of territorial areas with landslides potential(Tufescu V., 1966)Maps of soil stability in Romania (PROED S.A., 1966)Romania’s land zoning in terms of potential forlandslides (Marchidanu E, 1995)Territorial map of landslides (UTCB, 1997)Macro‐zoning map of induced landslides risk inRomania (GEOTEC S.A., 1998).


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During the last decade, some research institutes have beeninvolved in several international projects having landslidesusceptibility/hazard/risk assessment as a main goal:

Risk Assessment Methodologies for Soil Threats ‐RAMSOIL(2007‐2010);Hazard Risk Mitigation And Emergency PreparednessProject In Romania (2008‐2012)Living with landslide risk in Europe: Assessment, effects ofglobal change, and risk management strategies ‐ SafeLand(2009‐2012);Changing Hydro‐meteorological Risks as Analyzed by a NewGeneration of European Scientists – CHANGES (2011‐2014). Enabling CLimate Information Services for Europe – ECLISE(2011‐2013)


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RiskAssessmentMethodologiesforSoilThreats‐ RAMSOIL(2007‐2010)www.ramsoil.eu The general objective was to provide scientific guidelines on currentrisk assessment methodologies of soil threats encountered within EUMember States;

The selected soil threats were: erosion, salinisation, organic matterdecline, compaction and landslides.

For Romania, NATIONAL RESEARCH AND DEVELOPMENT INSTITUTEFOR SOIL SCIENCE AGRO‐CHEMISTRY AND ENVIRONMENT ‐ ICPABucureşti has elaborated methodology for estimating the areas with riskfor three types (from five) of soil degradation analyzed: compaction,salinisation, erosion.


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Living with landslide risk in Europe: Assessment, effects ofglobal change, and risk management strategies ‐ SafeLand(2009‐2012).http://www.safeland‐fp7.eu/ SafeLand is a Large‐scale integrating Collaborative research projectfunded by The Seventh Framework Programme for research andtechnological development (FP7) of the European Commission. The project team was composed of 25 institutions from 13European countries. From Romania, the responsible institution was GEOLOGICALINSTITUTE OF ROMANIA.


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ChangingHydro‐meteorologicalRisksasAnalyzedbyaNewGenerationofEuropeanScientists– CHANGES(2011‐2014).http://www.changes‐itn.eu/ The main objective of project is how global changes, related toenvironmental and climate change as well as socio‐economical change, willaffect the temporal and spatial patterns of hydro‐meteorological hazards andassociated risks in Europe; how these changes can be assessed, modeled, andincorporated in sustainable risk management strategies, focusing on spatialplanning, emergency preparedness and risk communication. CHANGES include 11 partner institutions that host one or moreresearchers and 6 associate partners that co‐supervise research projects,offer internships and participate in CHANGES network events. Romanian partner is the INSTITUTE OF GEOGRAPHY ‐ ROMANIANACADEMY. Case study chosen from Romania is Buzău County.


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A series of normative acts published in several stages, such as:

Law 575/2001, Law 124/1995, Government Decision 382 and 447/2003, Common Order of the Ministry of Public Works andTerritorial Planning, of the Chief of Department for Local PublicAdministration and Ministry of Waters and EnvironmentalProtection no. 62/N‐19.0/288‐1.955/1998, based on theWriting guide for landslides risk maps to ensure constructiondurability – Indicative GT‐019‐98

set the methodological norms regarding elaboration way andcontent of the landslides hazard maps based on calculating of theaverage coefficient of hazard K(m) .


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For drawing the map of landslide hazard are required the followingsteps:

dividing the territory for which the hazard map is elaborated in boundedpolygonal surfaces to represent as homogeneous lithologic and structuraldeposits ;estimating the weights and geographical distribution of “riskcoefficients” K(a‐h) depending on the criterion presented in Table 1; calculating the average hazard coefficient K(m) corresponding to eachanalyzed polygonal surface by using a specified formula (1); :determining the degree of potential (low , medium, high) associated witha certain probability of landslides occurrence (practically zero, low,medium , medium ‐high , high and very high ) .

hgfedcba

m KKKKKKKKK

6)(

Where:Ka = lithologic criterion;Kb = geomorphological criterion;Kc = structural criterion;Kd = hydrological and climatic criterion;Ke = hydrogeological criterion;Kf = seismic criterion;Kg = forest cover criterion;Kh = anthropogenous criterion,

expressed through a scale from 0 to 1OvidiusUniversityofConstanta

Faculty ofNaturalandAgriculturalSciences‐ (Partnerno4)

(1)


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Among the landslide affecting factors, lithology and geomorphologyare considered the most important.

DependingontheK(m)coefficient’svalue,areestablishlandslideoccurrencepotential:

lowpotential,K(m)<0.1mediumpotential,K(m)=0.1to0.3medium‐highpotential,K(m)=0.3to0.5 highpotential,,K(m)=0.5to0.8 high‐veryhighpotential,K(m)areabove0.8.

Legend:


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Table1.Rating‐Criterionforlandslidepotentialandprobabilityoccurrenceassessment


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Macro‐zoningmapofinducedlandslidesriskinRomania


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Mapoflandslidestypes‐ Romania


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COMMENTS:

In the absence of chronological information on the occurrenceof landslides, spatial–temporal probabilities cannot be calculatedand consequently predictions must be restricted to the spatialdistribution of future landslides; that is susceptibility (Bălteanuet al., 2010). There is no information regarding the differentiation betweenlandslide types in the present methodology.


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ADVANTAGES:

gives an overview relatively suggestive of areas withdifferent landslide potential;integrates data generally easier to find;can be used in case of lack information about theexistence of landslides (obtained from inventory usingdifferent sources).


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WorldBankProjectonnaturaldisastersstudyinRomania,coordinatedbyRMSI(RiskManagementSolutionsIndia).

HazardRiskMitigationAndEmergencyPreparednessProjectInRomania(2008‐2012)

Main goals:‐ executionofgeologicalandgeotechnicalstudiesontwopilotareasforthedesignandimplementationofan“insitu”monitoringsystem(includinginstallationofmonitoringequipment);‐ datacollectionandprocessingforelaborationofamodelforlandslidesanticipation;‐ elaborationofamonitoringmanualincludingelementsofanearlywarningsystem;‐ designandimplementationofatrainingprogramforlocalauthorities.


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More recent, Bălteanu et al., in2010, have developed a landslidesusceptibility model for the wholecountry applying a scoring system toa set of conditioning factors basedon expert judgement (heuristicmodel).This research was carried out dueto a World Bank project on lossesand insurance costs relating todisasters in Romania, and aims toprovide a unitary basis foraddressing landslide susceptibilityin the country.

It takes into account the mostimportant triggering factors, as well assettlements and infrastructure affectedby landslides. It also forms the basis for elaborationof a landslide‐hazard risk map in anattempt to quantify all potential lossesrelated to this process.


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Was used a Landslide Susceptibility Index(LSI) method based on quantitativelydefined weighted values.Expert analysis, combined with a longhistory of landslide mapping andassessment and field experiments, play animportant role in this method.The expert judgement involved a largenumber of studies and assessmentsundertaken at different scales, andgeomorphological mapping of Romanianterritory at the scale of 1:200,000.

Triggering FactorsIn computing a GIS landslide‐susceptibilitymap of Romania six major triggering factorswere considered:

lithology,height difference,slope angle,land use,rainfallseismicity.

Each factor was classified under sub‐classescarrying a rating from 0 to 10 according to itsrelevance for landslide susceptibility.Further, each factor was considered to havea differential influence on such susceptibility,named ‘assigned weight’.


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The results were compared withdifferent assessments from severalcountries.To validate the methodology,besides expert judgement, repeatedgeomorphic mapping over a longperiod, as well as field observationsand measurements in the mostaffected regions, were used.

Figure shows an example of a lithology rating mapbased on 1:200,000 scale map elaborated by theInstitute of Geology, Romania.


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The established classes are: ‘no susceptibility’,represents around 39% ofRomania (plains and lowhills),‘low’, 10%, ‘medium’, 38.3%,‘high’ and ‘very high’susceptibility, classesaround 10% (mostly in theSubcarpathian region).

SusceptibilityClassesThe LSI was further classifiedunder five hazard classes; eachcategory based on correlation ofexpert judgement and existinggeomorphological maps of thewhole of Romania.


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IncREO ‐ Increasing Resilience through Earth Observationhttp://www.increo‐fp7.eu/(Jan.’13– Dec.’14).

The objective of the work package which includes RomanianSpace Agency –ROSA, is to assess and map in a detailed mannerthe risk and vulnerability of areas in Romania highly prone tolandslides in the Buzau County.


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CHANGESFP7,IncREO FP7 Inventar

Fotointrepretare stereografica digitala(2005,2008)(Micu etal.2014):

1028alunecari profunde;800km2


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The map shows the landslide susceptibility ofBuzau County, Romania.For assessing the susceptibility of landslide proneareas a quantitative inventory‐based probabilisticmethod with the approach of “Weight ofEvidence” (WofE) was chosen.The following inputs were used:

Landslide inventory (kindly provided by the FP7CHANGES project),

DEM (slope, aspect, relative relief),

geology,

land use,

max. rainfall in 72 h,

distance to drainage network.

It is assumed that the landslide inventory iscomplete


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FP7 ECLISE• Logistic Regression (altitudinea; declivitatea suprafetelor; expozitia suprafetelor; curbura totala a suprafetelor; curbura in plan a suprafetelor; curbura in profil a suprafetelor; formatiunile litologice;grupele hidrologice de sol; acoperirea terenurilor.)

Indice compozitalfactorilordeclansatori(pp.maxin72hsi PGA)

Hartadehazardrelativlaalunecarideteren

Hartadesusceptibilitate laalunecarideteren (logisticregression)


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FP7 ECLISEVulnerabilitate: fizica, sociala,

de mediuFP7 ECLISEHarta de risc


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The methodology provided by the Ministry of Local PublicAdministration in 1998, 2001 and 2003 it is subjective and difficult toapply (Șandric et al., 2011), due to the uncertainties and differentinterpretations of the specialists that may occur in assigning weights tovarious landslide controlling factors in assessing susceptibility.Presently, there is no coherence and cohesion in decisions and actionstaken by the research institutes and government institutions involved,at local or regional scale in systematic investigation, or a strategy forinventorying and monitoring of landslide affected areas, at nationalscale.Moreover, although a general trend of unification between theRomanian and the international terminology regarding landslidesusceptibility, hazard and risk has been observed in recent years, thepresent methodological requirements underlying the legal frameworkare not updated.

CONCLUSIONS

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