risk analysis of geological hazards and disaster management
DESCRIPTION
Presentation made at The University of Sheffield to students of Environmental Science courseTRANSCRIPT
Risk Analysis of Geological Hazards and Disaster Management
Dr Claudio J Ferreira
The University of Sheffield
2008 2
ContentsRisk definition
Hazard
Vulnerability
Damage
Risk Mapping
Analytical or Synthetic approaches
Examples
GIS role
Disaster Management
2008 3
Risk definition
R = H x V x D, where
R=RiskH=HazardV=VulnerabilityD=Damage
Process
Element at risk
What is the difference between risk and hazard?
2008 4
Hazard definition
Hazard is the probability of occurrence, within a specific period of time in a given susceptible area, of a potentially damaging phenomenon. Hazard appraisal is obtained by the following equation:
Hazard = extension (area) x frequency (time) x magnitude (strength) of the events
2008 5
Susceptibility
Phenomenon
Event
Accident
Disaster
any event, circumstance, or experience that is observable
an important happening but without social losses
a happening that results in injury, loss, damage
any happening that causes great harm or damage
predisposition of a place to occurrence of certain phenomenon
2008 6
Disaster any happening that causes great harm or damage
For example, at least one of the following criteria must be fulfilled to be considered a disaster at UN/ISDR secretariat:
* 10 or more people reported killed
* 100 people reported affected
* Declaration of a state of emergency
* Call for international assistance
http://www.unisdr.org/disaster-statistics/introduction.htm
2008 7
Disaster ClassificationDisasters
BiologicalGeologicalHydrometeorological
NaturalTechnological
Floods
Landslides, Mudflows, Avalaches, Tidal Waves
Windstorms
Typhoons, Cyclones, Hurricanes, Storms (Winter, Tropical), Tornadoes
Droughts
Extreme temperatures, wildfires
Earthquakes Epidemic
Volcanic Eruptions
Tsunamis
Insect Infestation
Chemical spills, explosion, radiation, transport accidents
Centre for Research on the Epidemiology of Disasters (CRED) School of Public Health, Catholic University of Louvain Brussels, Belgium http://www.cred.be - Annual Disaster Statistical Review: Numbers and Trends 2006
2008
Disasters
Physic Biological
Hydro-logical
Geolo-gical
Atmos-pheric
Fauna Flora
ExogenousEndoge-nous
Natural SocialTechno-logical
Disaster Classification
2008 9
Risk Analysis is always:probabilityforecastpredictionprognosiscalculationestimative
Phenomenon, event, accident, disaster, catastrophe are always what had already happened, took place, occurred
Disaster Management
Response, resilience, capacity, recovery: Decisions and actions taken after a disaster
2008 10
EXAMPLES OF HAZARDS AND DISASTERS
2008 11
Malawi, East Africa
2008 12
2008 13
2008 14Debris flow
2008 15
2008 16Deep Soil Planar Landslide, Brazil
2008 17Shallow Soil Planar Landslide, Brazil
2008 18Ilhabela, São Paulo State, Brazil, Rock Boulder Slide
2008 19South Yorkshire, Peak District, UK, Slow Deep-Seated Slide
2008 20
2008 21
2008 22
2008 23
Vulnerability definition
Vulnerability is the condition determined by physical, social, economic, and environmental factors or processes, which increase the susceptibility of a community to the impact of hazards.
Element at risk: people, facilities, buildings, cars, environment, properties, economical processes
2008 24
Vulnerability is an intrinsic characteristic of the element at risk, but hazard dependent as well.
2008 25Diadema, São Paulo State, Brazil
2008 26Diadema, São Paulo State, Brazil
2008 27Sheffield, North Yorkshire, UK
2008 28
What is more vulnerable?
Oak
Reeds
2008 29
2008 30
Damage definition
Damage is a valuation of the element at risk. It may be estimated in the form of loss of life and injuries and/or loss of land and properties.
Dwellings = number of people
Roads = extension (meters)
2008 31Campos do Jordão, São Paulo State, Brazil
Number of the houses
2008 32Diadema, São Paulo State, Brazil
2008 33J. Remondo et al. / Geomorphology 94 (2008) 496–507
2008 34
RISK MAPPING1) To determine the study area and scale
2) To define the unity of analyses
3) To specify the attributes that qualify the process (hazard) and the element at risk (vulnerability and damage)
4) The GIS (Geographical Information System) role
2008 35
1:50,000 SCALE LANDSAT SATELLITE IMAGE, 30m resolution: a town, a region
Ubatuba, São Paulo State, Brazil
2008 36
1:10,000 SCALEIKONOS SATELLITE IMAGE1m resolution:a district, a neighbourhood
Ubatuba, São Paulo State, Brazil
2008 37
1:3,000 SCALE AERIAL PHOTO IMAGE, 1m resolution: a hill, a quarter, an area
Ubatuba, São Paulo State, Brazil
2008 38
RISK MAPPING1) To determine the study area and scale
2) To define the unity of analyses
3) To specify the attributes that qualify the process (hazard) and the element at risk (vulnerability and damage)
4) The GIS (Geographical Information System) role
2008 39
Parametric or Analytical
Geomorphology
Vegetation
Pedology
Geology
Two types of approaches
Physiographical or Synthetic
2008 40
Parametric or Analytical
Concept: Earth surface is the result of a vertical overlay of different components or “information layers”
Thematic maps
Assessment of individual layers (maps)
Physiographical or Synthetic
Concept: Earth surface is a mosaic formed by horizontal joining of homogeneous units, described by their attributes
Hierarchical subdivision of the territory
Assessment of Integrated units
2008 41
TURRINI, M C; VISINTAINER, P. 1998. Proposal of a method to define areas of landslide hazard and application to an area of the Dolomites, Italy. Enginneering Geology, 50:255- 265.
G e o l o g i c a l – t e c h n i c a l m a p
G e o l o g i c a l – s t r u c t u r a l m a pC o n t o u r l i n e t o p o g r a p h i c m a p
L a n d u s e a n d l a n d c o v e r m a p
2008 42
Parametric or Analytical
Characteristics:Necessity to produce many thematic layers
(geological map, geomorphological map, soil map, land-use map, and so on);
Analysis units are “ephemeral” ones (if another map would be done with different layers the limits of the units would be others)
Analysis units are “artificial” ones (resulted of intersection of many layers); they are not terrain recognisable units;
2008 43
Physiographic or Synthetic
XDAB
CDXD
In a given area
Identification of terrain zones with similar physiographical aspects
Physiographical Compartmentalisation
Geoenvironmental Characterization
Thematic Cartography
XDAB
CDXD
Characterization of the attributes of the defined units
Classification and assessment to produce the intended map
2008 44
Physiographical or Synthetic
2008 45
Physiographical or Synthetic
Natural Units (a homogeneous mapping unit on the basis of geomorphological origin, physiography, lithology, morphometry, and soil geography)
terrain mapping units (TMU)
basic compartmentalisation unit (BCU)
homogeneous unit (HU)
Administrative Units (city, watershed, town, district, etc)
2008 46
Physiographical or Sinthetic
Characteristics:Analysis units are observably ones (resulted of image
interpretation and field observations); they are terrain recognisable units;
Analysis units are “permanent” ones (the same units can be used to produce different thematic maps)
Necessity to produce only the data required for the intended map;
2008 47
Example: Risk map for people related to landslide, Ubatuba, Brazil, 1:10,000 scale
2008 48
Landslide hazard map Ubatuba, Brazil, 1:10,000
Attributes:declivity,slope shape,drainage density,geological structures,soil,climatic aspects,land-use
No hazard
Low
Mode-rate
High
Very High
2008 49
Homogenous units land-use
2008 50
Vulnerability map Ubatuba, Brazil, 1:10,000
Attributes:planned or not planned urban occupation,consolidate or not consolidate urban occupation,building pattern (high or poor),sewage sanitation, water supply. waste collection, type of roads,people education and income (census data)
Very LowLowModerateHighVery High
2008 51
Damage map Ubatuba, Brazil, 1:10,000
Attributes:number of people
Very LowLow
Moderate
High
Very High
2008 52
RISK MAP FOR PEOPLE RELATED TO LANDSLIDE
2008 53
Example: Risk map for people related to landslide, Diadema, Brazil, 1:3,000 scale
2008 54
Urbanization and Increasing Hazards
Metropolitan Region of Sao Paulo
50km
Diadema city
2008 55
Population density of Diadema city: 12,063.8 people per km2
2008 56
UNPLANNED LAND OCCUPATION/ INATTENTION TO ENVIRONMENTAL MANAGEMENT
2008 57
STEPS OF THE WORK
1-Inventory of landsliding and flooding events
2- GIS processing of high resolution
imagery
3- Field work
4- GIS procedures and data interpretation
Target areas
Basis for field work,
quantification of dwellings and GIS
analysis
Hazard assessment, land use characterization, interviewing of residents, risk classification
Data interpretation
2008 58
METHODOLOGY
General criteria for risk classification
R1 Low
R2 Moderate
R3 High
R4 Very High
Geological and geotechnical factors
Evidences of land instabilities
Previous records of
events
Do not predisposing
Highly predisposing
Moderately predisposing
Highly predisposing
No evidences
Significant
Little
Large number
Absent
Frequent
Scattered
Frequent
Risk classes
2008 59
Geological, geotechnical and land use predisposing factors regarding risk assesment
High steepness of the hill slope
Vertical cut slope
Unsubstancial construction
Unconsolidated Tertiary Sediment
Distance from the river channel
2008 60
Evidences of land instability regarding risk assessment
Undercutting Riverbank disruption
Mass movementWeathered rock or soil displacement or erosion
2008 61
Evidences of land instability regarding risk assessment
Increasing hazard rating
2008 62
GIS interface
R1
R2
R3
R4
2008 63
GIS role
Data representation:maps, profiles
Spatial analyses of geographical data:geostatistics
Digital terrain models
Data bank
Experts systems
2008 64
DISASTER MANAGEMENT
http://www.pdc.org/emi
2008 65
Preparedness:Activities and measures taken in advance to ensure effective response to the impact of hazards, including the issuance of timely and effective early warnings and the temporary evacuation of people and property from threatened locations
2008 66
OBSERVATION Monitoring and forecasting
ATTENTION Field inspection
ALERT Restricted people remotion
MAXIMAL ALERT Extensive people remotion
Awareness:The provision of timely and effective information, through identified institutions, that allows individuals exposed to a hazard to take action to avoid or reduce their risk and prepare for effective response.
Early warning systems include a chain of concerns, namely: understanding and mapping the hazard; monitoring and forecasting impending events; processing and disseminating understandable warnings to political authorities and the population, and undertaking appropriate and timely actions in response to the warnings.
Leavel of warning Actions
2008 67
Relief / response The provision of assistance or intervention during or immediately after a disaster to meet the life preservation and basic subsistence needs of those people affected. It can be of an immediate, short-term, or protracted duration.
Recovery Decisions and actions taken after a disaster with a view to restoring or improving the pre-disaster living conditions of the stricken community, while encouraging and facilitating necessary adjustments to reduce disaster risk.
2008 68
Unnatural Disaster Growing Impacts
Random urban growth
Natural resources and environmental deterioration
Obsolete construction codes
Reactive and centralist disaster attention paradigms still prevail
Hazards increasingly strength and frequency
Vulnerable constructions and productive activities
Weak risk management institutions
Inadequate capacity for risk management
Population incapable of assessing its vulnerability and confronting emergencies
Inadequate management of natural resources
Inadequate territorial management
Decision makers lack awareness and willingness
Obsolete risk management legislation
Underestimation of hazards
Inadequate development model
Based in Sergio Mora 2006
Many Thanks,
Dr Claudio J FerreiraResearcher - Environmental and Applied Geology Section - Geological Institute, Sao Paulo, Brazil
Current address:
Department of Structural and Civil Engineering - The University of Sheffield - Post-Doctoral ProgrammeSir Frederick Mappin BuildingMappin Street, Sheffield, S1 3JD, UKPhones: 0114 222 5056 (office)[email protected]