E nv ir o nm e nt al H az a rd s a nd Ri s k A sse ssm e n t a nd M an a ge m e n t C EG – IGOT – U L r is k a m .u l. p t
Status of nation-scale landslide
susceptibility mapping in Portugal
José Luís Zêzere
RISKam – Research Group on Environmental Hazard and Risk Assessment and Management
Centre of Geographical Studies
Institute of Geography and Spatial Planning University of Lisbon
Kick-off meeting
Project “Pan-European and nation-wide landslide susceptibility assessment” BGR, Berlin 16-18 October 2012
Outline
The Portuguese morphology
Morphologic / Geologic Units in Portugal
Landslide incidence in the Portuguese morphologic/geologic units Available Data
The Disaster Project Landslide Database Landslide Predisposing Factors
Landslide susceptibility assessment at the municipal scale
Methodology to assess and integrate landslide susceptibility in Portugal
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GTC-PROF DGF 2002 N Litologia Depositos Depositos glaciarios Metamorficas Plutonicas Sedimentares Vulcanicas Macrozonagem Funcional Uso/Função Dominante Fonte: IA (Atlas do Ambiente)
Km 20 0 20 Fonte: IA N
Carta litológica simplificada Reacção e resistência Ácidas brandas Ácidas duras Básicas brandas Básicas duras Complexos de rochas de dureza e acidez variáveis
Macrozonagem Funcional
20 0 20 Km Quartzitos
Outras rochas
Complexos xisto-grauváquicos Granitos e rochas afins Rochas ácidas
Rochas básicas
Rochas Ultrabásicas (Areias, arenitos, argilas, etc.)
(Margas, grés, etc.)
(Calcários, calcários dolomíticos, basaltos, etc.)
GTC-PROF DGF 2002
Simplified Lithology (reaction and resistance)
Acid rocks
Basic rocks
Ultrabasic rocks
Rock complex with variable hardness and ph
Acid soft rocks (sand, sandstone, clay) Acid hard rocks
Granit
Schist and greywacke Quartzite
Other rocks Basic soft rocks
(marl, sandstone, mudstone) Basic hard rocks
(limestone, dolomite, basalt)
Sedimentary loose deposits Glacial deposits Metamorphic rocks Plutonic rocks Sedimentary rocks Volcanic rocks Lithology
Hercynian Massif
Granit and residual soils • rockfall
• debris flows
Meta-sedimentary rocks
• slides (translational and rotational) • mud flows; debris flows
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Arcos de Valdevez
December 2000
Régua
Inactive Sedimentary Basins
Marls,clays and sandstones (Upper Cretaceous age) • rotational slides
• complex slope movements
Limestones and marls (Middle Cretaceous age) • translational slides
Marls and limestones (Upper Jurassic age) • slides (rotational and translational)
• mud flows
Complex slope movement (slide-flow)
Quebradas (Fanhões)
Active Sedimentary Basin
Clays (Miocene age)
• shallow slides (rotational and translational)
Sandstones, limestones and clays (Miocene age) • shallow slides (rotational and translational)
• rockfall
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Available Data
DISASTER - GIS database on hydro-geomorphologic disasters in Portugal: a tool for environmental
management and emergency planning PTDC/CS-GEO/103231/2008
Funded by the Portuguese Foundation for Science and Technology (FCT)
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National hydro-geomorphological Disaster Database
Criteria:
any flood or landslide that caused either casualties, injuries, missing, evacuated or homeless people, independently of the number of people.
Period: 1865 - 2010
Ocurrence: Georeferenced place affected by a flood or a landslide that
caused either casualties, injuries, missing, evacuated or homeless people.
Event: Date or time period characterized by the occurrence of floods
and/or landslides that caused either casualties, injuries, missing, evacuated or homeless people.
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THE DISASTER PROJECT DATABASE
riskam.ul.pt 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 90.0 100.0 0 2 4 6 8 10 12 14 16 18 65 18 70 18 75 18 80 18 85 18 90 18 95 19 00 19 05 19 10 19 15 19 20 19 25 19 30 19 35 19 40 19 45 19 50 19 55 19 60 19 65 19 70 19 75 19 80 19 85 19 90 19 95 20 00 20 05 20 10 Cu m ul ti ve L an ds lid es (% ) La nd sl id es
Landslides Cumulative landslides
riskam.ul.pt 0.0 5.0 10.0 15.0 20.0 25.0 30.0
Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug
(%
)
floods landslides
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Spatial distribution of Disaster Project landslides (281 cases)
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Landslide predisposing Factors (National Scale)
DEM Elevation Slope Aspect (?) Lithology Soil type Morpho-geologic Units
Vegetation and Land use (COS_07) Ecological Units
Mean Annual Precipitation Available Water (P-ETP)
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Landslide predisposing Factors (National Scale)
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Landslide predisposing Factors (National Scale)
Soil Type Lithology
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Landslide predisposing Factors (National Scale)
Land Use Morpho-Geologic Units
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Landslide predisposing Factors (National Scale) Ecological Units
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Landslide predisposing Factors (National Scale)
P-ETP Mean Annual Precipitation
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Uncertainty regarding the exact landslide location in some cases The need to model using terrain mapping units
(geologic/hidrographic)
Lithologic Unit
Critical slope (°)
Loose sedimentary deposit 10
Limestone 25
Granite 25
Quartzite 25
Stratified sedimentary and volcanic rocks
10
Other volcanic rocks 20
Schist 15
riskam.ul.pt N Macrozonagem Funcional Densidade da população residente (2001) 0 - 10 10 - 20 20 - 100 100 - 200 200 - 600 600 - 32 000 Fonte: INE 20 0 20 Km GTC-PROF DGF 2002 hab/km2 Population Density (2001)
Disaster Project landslides distribution and Population density in Portugal
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21 selected municipalities where detailed landslide inventories are available (total landslides: 7200)
riskam.ul.pt DISASTER Project landslide database Portugal mainland Detailed Landslide Inventories Selected Municipalities Geographic Database Landslide predisposing factors
Landslide susceptibility modelling
Terrain mapping unit to define (geologic, geomorphologic, hidrographic)
Portugal mainland (1: 500 000)
Pixel Terrain Units
Selected municipalities (1: 25 000)
Heuristic (?) Data Driven (LR ?)
Landslide susceptibility Map I (1:500 000) Landslide susceptibility (1:25 000) • Falls • Slides • Flows Validation Integration
Landslide susceptibility Final Map (1:500 000)
Weighting of landslide predisposing factors at
the national scale Generalization
Landslide susceptibility Map II (1:500 000)
RESULTADOS PRELIMINARES - MOVIMENTOS DESENCADEADOS POR SISMOS
Localização das descrições de movimentos de vertente com desencadeamento sísmico.
• Identificados 29
movimentos de vertente desencadeados pela actividade sísmica;
• Intervalo de tempo que vai
desde os anos de 309-382 até 28 de Fevereiro de
1969.
Distribuição espacial dos movimentos
Localização de movimentos de vertente descritos com desencadeamento sísmico e isossistas de intensidade máxima
da sismicidade histórica e actual.
• Concentração dos movimentos desencadeados
por sismos no centro e sul do país;
• A distribuição segue de perto as isossistas da
sismicidade histórica e actual;
• A maior parte dos movimentos (90%)
verificou-se nas zonas de intensidade sísmica VIII, IX e X.
Distribuição dos movimentos de vertente com desencadeamento sísmico por zonas de intensidade de intensidade máxima.
0 10 20 30 40 50 60 V VI VII VIII IX X % Zona de intensidade
PLANODEDOUTORAMENTOEM GEOGRAFIA FÍSICA
RESULTADOS PRELIMINARES - MOVIMENTOS DESENCADEADOS POR
