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28/05/2012
1
RISK ASSESMENT AND MANAGEMENT
OF EARTHQUAKE DISASTER
Prepared by:
Sutikno
Reference1. Nott, J. 2006.Extreem Events. A Physical Reconstruction and Risk Assessment.
Cambridge University Press. Cambridge.
2. Abbott. P.2004. Natural Disaster. McGraw Hill. New York.
3. Bryan, E. 2005. Natural Hazard. Cambridge University Press. Cambridge.
4. Smith K. 1996. Environmental Hazard. Assessing Risk and Reducing Disaster. Routledge. New York.
5. I Wayan SEngara; Enghan K. Kertapati; Khrisna S. Pribadi.2004. Penegembangan Model Kajian Singkat Bencana Gempa untuk Kota-Kota di Indonesia. Prosiding Konferensi Nasional Rekayasa II. Yogyarta. PIST.
6. Kirbani. S.B.2009. Seismic Hazard, Their Mapping and Management in Indonesia. Lecture note on Geo-information for Spatial Planning and Risk Management. Yogyakarta Gadjah Mada University-ITC The Netherlands.
7. Glade, T; Anderson, M; Crozier, M.J. (ed), 2006. Landslide Hazard and Risk. John Wiley & Sons.
8. Iftekhar Ahmed K. 2006. Risk Management. Workshop: Earthquake Vulnerability Reduction for City and Damages and Loss Estimation. September 2006. Yogyakarta. ADPC, PSBA, SNV.
9. Teddy Boon. 2006. Earthquake Hazard, Risk Assessment. Workshop: Earthquake Vulnerability Reduction for City and Damages and Loss Estimation. September 2006. Yogyakarta. ADPC, PSBA, SNV.
10. Itc module
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REVIEW TERMINOLOGY OF
HAZARD, RISK, DISASTER1. Hazard:
• is an inescapable part of life.
• is as a naturally occurring or human induced process or event with potentially to create loss, i.e. a general sources of danger.
• as a potential threat to humans and their welfare.
2. Risk:• is some time taken as synonym with hazard but risk has
the additional implication of the chance of a particular hazard actually occurring
• as the probability of specific hazard occurrence
3. Disaster:• when large numbers of people exposed to hazard are
killed, injured or damaged;
• As the realization of hazard.
RISK
1. Risk: • a measure of the probability and severity of loss to
the element at risk, usually expressed for unit area, object, or activity, over a specified period of time;
2. Risk analysis: • the overall process involving scoping, hazard and
identification and risk estimation.
3. Risk assessment: • the combination processes of risk analysis and risk
evaluation, leading to the stage where personal judgments and treatment decision can be rationally made
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RISK
4. Risk management:
• the process of developing and applying policies,
procedure and practices to the tasks of
assessment, monitoring, communication and
treatment of risk.
5. Specific risk:
• hazard probability x vulnerability for a given
elements at risk and/or for a given type of
process.
RISK
6. Tolerable risk: • level of risk that society is prepared to live with
because there are net benefits in doing so, as long as that risk is monitored and controlled and action is taken to reduce it.
7. Total risk: • the expected consequences (loss) resulting from
the level of hazard in a place, over a specified time period. It depends on not only on the different hazardous process involved but also on elements at risk and their vulnerability
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VULNERABILITY
Vulnerability:
• the expected degree of loss experienced by
the elements at risk for a a given magnitude
of hazard.
GENERIC HAZARD-RISK EQUATION
Risk = (hazard x vulnerability x element at risk
Element at risk:
1) physical
2) facilities
3) economic
4) societal
5) environmental
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Quantification of Risk
• Three essential components to
quantification of hazard:1) Hazard occurrence probability (p)
2) Element at risk
3) Expected loss (L)
Risk Assessment
• It is the overall process of identifying and
analyzing risk.
• The process of characterizing hazard
within risk area, analyzing them for their
potential mishap consequences and
probabilities of occurrence and combining
the two estimate to reach a risk ranking
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Risk as function of hazard, loss and
preparedness
Risk =Hazard (probability) x Loss (expected)
preparedness (loss mitigation)
1) Greater the hazard probability, greater the risk
2) Greater the loss, greater the risk
3) Greater the preparedness or capacity of community,
lesser the risk.
Methodology for risk assessment1) Define the geographic area to be studied.
2) Identify the type and amount of data needed to complete the risk assessment
3) Identify the potential hazards within the risk area.
4) Identify the vulnerability.
5) Prepare an inventory of element at risk
6) Apply hazard specific damage quantitatively or rank potential damage qualitatively.
7) Apply loss function to damage results to estimate level of financial, personal, or property losses quantitatively or rank potential losses qualitatively.
RISK MAPPING
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Varying Scale of Hazard, Risk and Disaster
the Threats can be recognized
1. Hazard to people:• death, injury, disease, stress
2. Hazard to goods:• property damage, economic loss;
3. Hazard to environment:• loss of flora and fauna, pollution, loss of amenity
DISASTER: LOCAL, REGIONAL, GLOBAL
2. TYPOLOGY OF HAZARD AND DISATER
1. Natural Geo-hazard1. Geologic hazard
2. Geomorphologic hazard
1. Hydro-meteorological hazard1. Flood
2. Drought
3. Typhoon
2. Biologic hazard
3. Technological hazard (Anthropogenic)
ENVIRONMENTAL HAZARDS
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DISASTER
1. Generally results from the interaction, in time and space, between the physical exposure to hazardous process and a vulnerable human population.
2. Criteria of significant disaster (CRED)• Number of death per event 100 or more;
• Significant damage: 1 per cent or more of the total GNP
• Affected people: 1 per cent or more of the total national population.
Reason why disaster impact is growing
1. Population growth
2. Land pressure
3. Urbanization
4. Inequality
5. Climate change
6. Political change
7. Economic growth
8. Technological innovation
9. Social expectations
10. Global interdependence
HOW TO REDUCE THE RISK
• NEED RISK ASSESSEMENT
• NEED RISK MANAGEMENT
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Relation between Hazard, Probability and
Risk
Disaster Risk
• The probability that a
community’s structure
or geographic area is
to be damaged or
disrupted by the impact
of a particular hazard,
on account of their
nature, construction,
and proximity to a
hazardous area
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10
Risk reduction study
Study Area
Physical phenomena Cultural phemena Sosekbud
H1,H2, H3, H4…….Hn
R1,R2, R3, R4, …..Rn
Hazard multi-risk
V1, V2, V3, V4, …..Vn
Local comunity
Local wisdom
Capacity
Coordination sistem disaster risk reductin
Elements at Risk
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Vulnerability
“... a human condition or process resulting from physical, social, economic, and environmental factors which determine the likelihood and scale of damage from the impact of a given hazard“ (UNDP, 2004)
“... the likelihood of injury, death, loss, disruption of livelihood or other harm in an extreme event, and/or unusual difficulties in recovering from such effects“(Wisner, 2002)
ELEMENTS AT RISK:
Human, Houses, Water Supplies, Social Group and
Network, Crops, Livestock, Savings, Jobs, Natural
Environment
VULNERABLE CONDITIONS:
1) ECONOMIC: fragile livelihoods; no credit and saving
facilities
2) NATURAL: dependence on very few natural resources
3) CONSTRUCTED: structural design; location of houses on
an stable slope
4) INDIVIDUAL: lack of skills or knowledge; lacking opprotunity
due to gender; being old or very young; living with HIV or
AIDS
5) SOCIAL: disorganized or fragmented society; bad
leadership
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Capacity
• kombinasi dari segala
kemampuan dan
sumberdaya yang ada di
dalam komunitas,
masyarakat, atau
organisasi yang dapat
menurunkan tingkat risiko
atau dampak suatu
bencana (UNISDR, 2002).
• Capacities are those
positive condition or
abilities which increase a
community’s ability to deal
with hazards.
9.4. Coping Capacity
• The means by which people or
organizations use available resources and
abilities to face adverse consequences that
could lead to a disaster. In general, this
involves managing resources, both in
normal times as well as during crises or
adverse conditions.
• The strengthening of coping capacities
usually builds resilience to withstand the
effects of natural and human-induced
hazards.
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9.5. Capacity Building
• Efforts aimed to develop human skills
or societal infrastructures within a
community or organization needed to
reduce the level of risk.
• In extended understanding, capacity
building also includes development of
institutional, financial, political and
other resources, such as technology at
different levels and sectors of the
society.
10.Disaster Risk Management
A broad range of activities
designed to:
• Prevent the loss of lives
• Minimize human suffering
• Inform the public and
authorities of risk
• Minimize property damage
and economic loss
• Speed up the recovery
process
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Prevention
• Measures taken to
avert a disaster
from occurring, if
possible (to
impede a hazard
so that it does not
have any harmful
effects).
10.2.Mitigation
• Measures taken
prior to the impact
of a disaster to
minimize its effects
(sometimes
referred to as
structural and non-
structural
measures).
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Preparedness
• Measures taken
in anticipation of a
disaster to ensure
that appropriate
and effective
actions are taken
in the aftermath.
Relief
• Measures that
are required in
search and
rescue of
survivors, as well
to meet the basic
needs for shelter,
water, food and
health care.
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10.5. Recovery
• The process
undertaken by a
disaster-affected
community to fully
restore itself to
pre-disaster level
of functioning.
10.6.Rehabilitation
Actions taken in the
aftermath of a disaster
to:
• assist victims to repair
their dwellings;
• re-establish essential
services;
• revive key economic
and social activities
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Reconstruction
• Permanent measures
to repair or replace
damaged dwellings
and infrastructure and
to set the economy
back on course.
INDIVIDUAL ASSIGNMENT 1
Key Question on Hazard,
Vulnerability, and Capacity
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Key questions to Hazard
Is there any phenomenon to environmental degradation?
What is the level of the occurrence?
Where is the location?
Who are suffered from the phenomena?
When is the phenomena occurred?
How often is the phenomena occurred?
How to solve the problem?
Who will take the responsibility?
Key question to Vulnerability
Who or what vulnerable to the
impacts of hazard?
Where or when them vulnerable?
What social, physical and
environmental factors make them
vulnerable?
How vulnerable are they?
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Key question to Capacity
What are the variables to measure
it?
Who have the capacity?
How are the mechanism?
Who are responsible for it?
How to increase the capacity?
3. HAZARD, RISK ASSESSMENT
OF
EARTHQUAKE
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1. EARTHQUAKE: WHAT IS IT?1) The sudden shaking of the earth in response to the rocks
movement such as plate tectonic movement, fault or
volcanic activity
2) Shaking of the ground caused by sudden release of energy
storing in the rocks beneath earth surface
2. EARTHQUAKE TYPES: 1) Tectonic
2) Volcanic
3) Mass-movement (collapsing)
4) Meteoric hitting
HOW AND WHERE EARTHQUAKE OCCURED
1. Earthquake occurred:
Sudden release of energy
2. Location of energy releasing as focus of the earthquake:
Collision of the plate tectonics
Fault zones
Volcanic activity
3. Earthquake zones
ring of fire
plate tectonic collision’s zone
Indonesia (map of Indonesia)
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Some characteristics of earthquake
1) Usually no warning, except for
secondary shocks.
2) Speed of onset usually sudden.
3) Earthquake-prone areas are generally
well defined and well known.
4) Major effect arise from land movement,
etc.
5) Many secondary hazards.
EARTHQUAKE DATA OF THE EARTH
Magnitude (RS) Frequency
Number/year
Criteria
> 8,5 0,3 very huge
8-8,4 1
7,5-7,9 3
7-7,4 15 huge
6-6,9 56
6-6,5 210 strong
5-5,9 800 medium
4-4,9 6.200 light
3-3,9 49.000 small
2-2,9 (0-1,9) 350.000 (3.000.000) very small
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Classification of earthquake
according to the magnitude
1) under 5 : small
2) 5-6 : moderate
3) 6-7 : large
4) 7-7.8 : major
5) > 7.8 : great
Damage caused by ground shaking
Depend on:
1) Size : magnitude and intensity
2) Depth
3) Attenuation
4) Duration
5) The site response
Relate to the traveling distance
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TYPES OF EARTHQUAKE WAVE:
1. Surface wave:
• traveling on the earth surface
2. Body wave:
• Traveling through Earth’s interior, direct
from hypocenter
3. Wave type:
• Primary wave (P)
• Secondary wave (S)
• Love wave
• Raleigh wave
EARTHQUAKE’S WAVE TYPES
1. Primary wave
2. Secondary wave
3. Love wave
4. Raleigh wave
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Seismic waves
• Body waves– P-Waves
• Primary, Compressional, Longitudinal. Fast. Trough all media (gas, liquid, solid)
– S-Wave• Secondary, Shear,
Transverse. Only solids
• Surface waves– Love wave
• Similar to S-waves
– Rayleigh wave• “Surface ripples” Interaction P
and S waves.
IMPACTS OF THE EARTHQUAKE
1. Tsunami
2. Liquefaction
3. Landslide
4. Fire
5. Flood
6. Permanent displacement of the land
surface (FAULT)
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Directly related to crustal movement1. Ground shaking
2. Fault rupture
Indirect effects of earthquakes 3. Tsunamis
4. Seiches
5. Avalanches,
6. Land & mud slides,
7. Differential ground settlement,
8. Soil liquefaction.
9. Floods from dam and levee failures.
10. Fires, etc
Causes of earthquake damage
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Magnitude & Intensity
1. 2 ways of measuring strength of an earthquake:
• Magnitude: amount of energy released - "Small earthquakes make small waves, big earthquakes make big waves"
• Intensity: amount of damage, reaction of people
2. Magnitude scales:• Local magnitude scale (ML) (Richter scale)
• Surface wave magnitude scale (Ms)
• Body wave magnitude scale (Mb)
• Moment magnitude scale (Mw) (seismic motion)
What does the Richter Scale
Mean?
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Intensity of an earthquake (1)
1. Based on:• Observations of damaged structures
• Presence of secondary effects
• Degree to which quake was felt by individuals
2. Easy to determine in urban area, difficult in rural area
3. Most commonly used:• Modified Mercalli Intensity scale (MMI)
• MSK-64 (Medvedev-Sponheuer-Karnik)
• EMS-98(European Macroseismic Scale)
I. Instrumental Detected only by seismographs
II. Feeble Noticed only by sensitive people.
III. Slight Resembling vibrations caused by heavy traffic.
IV. Moderate Felt by people walking; rocking of free standing objects.
V. Rather strong Sleepers awakened and bells ring.
VI. Strong Trees sway, some damage from overturning and falling objects.
VII. Very strong General alarm, cracking of walls.
VIII. Destructive Chimneys fall and there is some damage to buildings.
IX. Ruinous Ground begins to crack, houses begin to collapse and pipes break.
X. Disastrous Ground badly cracked and many buildings are destroyed.There are some landslides.
XI. Very Disastrous Few buildings remain standing; bridges and railways destroyed;water, gas, electricity and telephones out of action.
XII. Catastrophic Total destruction; objects are thrown into the air, much heaving,shaking and distortion of the ground.
Modified Mercalli scale
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Seismic risk analysis
1. Macro seismic hazard analysis• Deterministic seismic hazard analysis (DSHA)
• Probabilistic seismic hazard analysis (PSHA)
2. Micro seismic hazard analysis• Soft ground effects analysis
• Liquefaction analysis
3. Vulnerability and risk analysis• Building vulnerability, vulnerability curves
• RADIUS, HAZUS approach
• Case studies
Micro seismic hazard analysis
1. Site effects• Soft ground effects
• Liquefaction
• Topographic effect
2. Methods for estimating site effects:• Soft ground effects:
– Numerical method: 1D response analysis (Shake)
– Nakamura’s or H/V method
• Liquefaction analysis
– “Simplified procedure” by Seed and Idriss
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How do seismic waves shake the
ground? 1) (Soft) soil overlying hard rock amplifies the
seismic signal in almost all cases
2) The amount of amplification depends on• Soil thickness
• Soil characteristics (stiffness, unit weight)
• Earthquake type (magnitude, hypocentre distance)
3) The largest amplification occurs when the soil starts to resonate under the influence of the seismic signal
4) Also in certain topographic situation there can be a major amplification
How do seismic waves affect
buildings and structures?1. Horizontal movements
(accelerations) of the ground surface are being transferred to the building
2. These horizontal accelerations create forces on a building or structure
3. Accelerations are largest when the building start to resonate
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Natural frequency of buildings1) Buildings tend to have
lower natural frequencies
when they are: • Either heavier (more mass)
• Or more flexible (that is less
stiff).
2) One of the main things that
affect the stiffness of a
building is its height.• Taller buildings tend to be
more flexible, so they tend to
have lower natural frequencies
compared to shorter buildings.
Type of object or structure Natural frequency (Hz)
One-story buildings 10
3-4 story buildings 2
Tall buildings 0.5 – 1.0
High-rise buildings 0.17
What do we use to quantify
the expected ground motion?1) Using peak ground acceleration
• Acceleration and force are in direct proportion
• Peak acceleration often correspond to high frequencies, which are out of range of the natural frequencies of most structures
2) Response spectra analysis• Current standard method for ground response
analysis
• Maximum ground response (amplification) for different frequencies
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Example of response spectrum
CCALA NS - Profile N. BrasiliaSa for 5% damping
Sp
ectr
al A
ccele
ratio
n (g
)
Per iod (sec)
0
1
2
3
4
5
6
0.01 100.1 1
Period (s)
Sp
ectr
al a
cce
lera
tion
(g)
1D ground response analysis
Assumptions• Inclined seismic rays are reflected to a near-vertical
direction, because of decrease in velocities of surface deposits
• All boundaries are horizontal
• Response of the soil deposit is caused by Shear waves propagating vertically from the underlying bedrock
• Soil and bedrock are assumed to extend infinitely in the horizontal direction (half-sphere)
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How do we do microzonation?1. Create a continuous (3D) ground model in GIS using
any available surface and subsurface information:• Boreholes, SPT’s
• Geophysical profiles (VES, refraction)
• (Engineering) Geological maps
• Any other a-priori geological knowledge of the “model builder”
2. Calculate seismic response for every surface point
on the continuous layer model (using SHAKE)
3. Visualize spatial variation of seismic response over
the entire modeled area using GIS
4. Classify seismic response analyses into areas with
different hazard levels (e.g. exceeding design
acceleration levels)
Soil amplificationSurface Ground Amplification
0.0
0.5
1.0
1.5
Hard Rock Soft Rock Medium Soil Soft Soil
Rock/Soil Type
Am
plif
icat
ion
Fac
tor
• Classification or zoning of ground conditions is
important in the earthquake damage estimation process
because ground conditions directly affect seismic
amplification of ground shaking.
• Radius adopts a simple classification, which with 4
classes with corresponding amplification factors.
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Building classes & vulnerability curves
Building Damage Curve
0
20
40
60
80
100
4 5 6 7 8 9 10 11 12
MMI
Dam
age R
ate
(%
)
RES1
RES2
RES3
RES4
EDU1
EDU2
MED1
MED2
COM
IND
Vulnerability functions define the relation between seismic intensity and damage rate for structural types are determined as the function of acceleration/MMI based on damage observed during past sample earthquakes.
Casualties
• Casualties can be
calculated from the
number of damaged
buildings
• The number of people
inside buildings during
the day and night is
usually not the same
since the ratio of
usage of buildings is
different.
Occupants at Time of Collapse
Trapped Untrapped
Don't Die InstantlyDie Instantly
Die Later Don't Die Later
Seriously
Injured
Moderately
Injured
Uninjured
or
Lightly
Injured
Moderately
Injured
Uninjured
or
Lightly
Injured
M3
M4d 1-M4d
M5 1-M5
M4s M4m M4l
M6 1-M6
1-M3
M1*(1-M2)*DamageCounts
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Potential Earth Science Hazards
Ground Motion Ground failure
Direct Physical Damage
Direct
Economic/Social
Losses
Induced
Physical
Damage
General building
stockEssential & High
potential loss facililities
Lifelines&
transportation systems
Lifelines utility
systems
Inundation Fire HazMat Debris Causalities Shelter Economic
Indirect economic losses: Modules are interdependent with out put
of some
modules acting as input to others
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Probabilistic seismic hazard maps
1) Made by USGS
2) Contour maps with PGA and spectral acceleration at periods of 0.3 seconds and 1.0 second
3) 8 hazard levels: from 39 % probability in 50 years, to 2 % probability in 50 years
4) Return periods: 100 - 2500 years
Amplification of Ground Shaking -
Local Site Conditions
• Amplification of ground shaking to account for local site conditions is based on the site classes and soil amplification factors proposed for the
1997 NEHRP Provisions
• The NEHRP Provisionsdefine a standardized site geology classification scheme and specify soil amplification factors for most site classes.
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Ground Failure
1. Three types of ground failure are considered:
1) liquefaction,
2) Land sliding and
3) surface fault rupture.
2. Each of these types of ground failure are
quantified by permanent ground deformation
(PGD).
Earthquake susceptibility factors
1. Position on the plate tectonic zone or on the
ring of fire zone
2. Geological structure, especially the fault
structure
3. Stratigraphy
4. Lithology
5. Unconsolidated sediment
6. Groundwater depth
7. Historical data
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Earthquake Risk
1) Is an estimate of the probability of
expected loss for a given destruction
even
2) Risk = (Hazard x potential loss)/preparedness
Potential losses due to earthquake
1) Direct losses
2) Indirect losses
3) Secondary losses
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Ranking of Risk
C B A A
C B B A
D C B B
D D C C
A Risk Matrix
P
R
O
B
A
B
I
T
Y
High
Medium
Low
Very Low
POTENSIAL LOSS
Low
Medium High Very High
Guideline may be used to do a matrix analysis
Probability Loss
High Events that occur more
frequently than one in 10 years
Based on the potential of
element at risk:
• fatalities
• injuries
• services, infrastructure
• properties damage
• environmental impact
• economic impact,
• etc
Medium Events that occur from one in 10
years to one in 100 years
Low Events that occur from once in
100 years to once in 1000 years
Very Low Events that occur less frequently
than once in 1000 years
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Criteria used for class categorization
(is subjective)
Class A • High risk condition, immediate action is necessary
• Possible deaths over 1000
• People affected may be over 100.000
• Complete shut down of facilities and critical services
more than 14 days
• Over 50% of property located in the area may be damaged
Class B • Moderate to high risk, risk can be reduced by mitigation
• Possible deaths less than 1000
• People affected may be between 50.000 to 100.000
• Complete shut down of facilities and critical services for 7 days
• 25% of the properties in the area may be damaged.
Class C • low risk condition, however mitigation and planning is necessary
• Possibility of death low
• People affected between 10.000 and 50 000
• Complete shut down of facilities not more than 1 day
• about 10% of the property located in the area may be damaged
Class D • very low risk, only limited action necessary
• no possibility of death
• people affecte less than 1000
• Fasilities not affected
• about 1% of the property located in the area may be damaged
Earthquake risk assessment
1. Is to evaluate the earthquake resistance
of the community’s built environment
2. Requires characterization of the
community’s hazard environment and it
built environment;, controlled by:• amplitude,
• frequency,
• composition,
• duration,
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Characterization of the built
environment for risk assessment:
1. Building exposed to earthquake hazards
2. Structural characteristics:• Construction material
• Soil foundation
• Structural foundation
• Structural system
• Building configuration
• Age and usage
• Exposure to prior earthquake
3. Lifeline system exposed to earthquake
Information on the built
environment for risk assessment
1. Location of engineered and non engineered
buildings in relation to soil deposit:• Building inventory
• Soil characteristics (composition, type and depth)
2. Location/route of lifelines systems in relation to
soil deposit:• inventory
• soil characteristics
3. Vulnerability/fragility relation for building and
lifelines
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Damage and loss estimation
1. Estimation of from structural damages:• Direct physical damage
• Indirect economic losses
• Death and injures
Risk management action planning
1. Assessment of the current level of risk
management preparedness.
2. Formulation of risk management activities.
3. Formulation of strategy for implementation.
4. Designation of the institution that would
implement the plan
5. Implementation of the action plan
6. Publication and dissemination of the action
plan