RESEARCH REPORT STUDY ON EARTHQUAKE RISK AND VULNERABILITY MANAGEMENT
Earthquake Risk Reduction Hazard, Vulnerability & Risk Assessment
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Transcript of Earthquake Risk Reduction Hazard, Vulnerability & Risk Assessment
Earthquake Risk Reduction 111
Earthquake Risk Reduction
Hazard, Vulnerability & Risk Assessment
Session 2World Bank Institute
Charles SCAWTHORN Junji KIYONO
Kyoto University
Earthquake Risk Reduction 222
SystemInput
Earthquake
Human/Social
Environment
Damage
Output
Hazard Vulnerability
Loss
Assessment
Outline of Risk Assessment
Keywords: Seismic Hazard, Attenuation, Hazard, Vulnerability, Loss Estimation
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Seismic Hazards
faulting
tsunamishaking
faulting
fire
landslide
liquefaction
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Liquefaction -1
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(Map Source: PHIVOLCS)
Liquefaction Susceptibility
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Tsunami
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Tectonics and Active Faults in the Philippines
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Detailed Fault Map
Valley Fault System, Pasig Quadrangle
1:10,000
(Source: PHIVOLCS)
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Historical Seismicity, 1608-1985, Metro Manila Region
(Source: MMEIRS, 2003)
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mbamN )(log
Gutenberg-Richter relation (b-value model):
4 5 6 7 8 Mw
N(m)
1.0
0.1
0.01
0.001
Magnitude-frequency relation is the N(m), the number of events equal to or greater than magnitude m. a is a regional constant, and b expresses the rate of seismicity. The simplest M-f relation is the Gutenberg-Ricter relation:
mbamN )(log
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Attenuation
Campbell, K.W. and Bozorgnia, Y. 2003. “Updated Near-Source Ground Motion (Attenuation) Relations for the Horizontal and Vertical Components of Peak Ground Acceleration and Acceleration Response Spectra,” Bull. Seismol. Soc. Am.
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Seismic Hazard Assessment
Map faults
Estimate EQ occurrence rates
Estimate attenuation
Combine data to estimate Hazard Curve
Provide various measures of the Hazard
PGA
Pe pa
Hazard Curve
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Hazard Maps (Source: MMEIRS)
Scenario Shaking Map
Liquefaction Potential Map
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Seismic vulnerability is the degree of loss causedby a given level of hazard.
Seismic vulnerability is a function of ground motion or other hazard intensities.
Typically, the most seismically vulnerable buildings are earthen and low-strength unreinforced masonry, such as stone and brick.
Other vulnerable types of buildings are older reinforced concrete buildings, and buildings with large ground floor openings.
Seismic Vulnerability
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Vulnerability of Reinforced Concrete Buildings - 1
Ordinary RC column in non-seismic area –few ‘lateral’ ties surrounding the longitudinal reinforcement
Ductile RC column for seismic area – many
‘lateral’ ties surrounding the
longitudinal reinforcement
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Vulnerability of Reinforced Concrete Buildings - 2
failed RC column on highway bridge1994 Northridge (US) earthquake
collapse of RC multistory hotel Baguio, 1990 Philippines
Broken RC column in collapsed building, 2005 SouthAsia earthquake – note small diameter lateral ties spaced far apart
Lateral ties
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Vulnerability can be represented as (a) a damage rate of buildings in a area, or as (b) a damage degree for a building itself.
Dam
age
rate
0%
50%
100%
Partial damageHeavy damage
Collapse
Seismic intensity
Dam
age
degre
e
0.0
0.5
1.0
Partial damage
Heavy damage
Collapse
Seismic intensity
Type I
Type II
Vulnerability function
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Mean Damage Functions
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
VI VII VIII IX X
MMI
LOW RISE WOOD FRAME
MED RISE RC SHEAR WALL (W/O MRF)
MED RISE BRACED STL FRAME
MED RISE R MOM RESISTG. NON-DUCT. RCFRAME-D
URM (BRG. WALL) LOW RISE (1-3 )
Example Vulnerability Functions
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Risk, probabilistic distribution of loss, can be estimated by combining vulnerability functions with the hazard data as shown in the following schematic figure.
Total annual expected cost experiencing severity of ground motion larger than a* is derived from a product of hazard and vulnerability. Hatched area is risk.
a*
Dam
age (
cost
rati
o)
when e
xperi
ence
se
veri
ty, a
0.0
0.5
1.0
Ground motion
severity, aC
ontr
ibuti
on o
f each
level
of
severi
ty t
o t
ota
l annual
cost
Ground motion
severity, a
Annual pro
babili
ty o
f experi
enci
ng s
everi
ty larg
er
than a
Ground motion
severity, a
p
a*
Hazard Vulnerability
Risk
Earthquake Risk - 1
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Earthquake risk is the uncertainty of loss over a specific future time.
Generally, risk is determined as:[R]i = [H]j x [V|H]ij
In which [R]i is the risk, probability or average rate of loss of
elementi due to earthquake intensity j,
[H]j the hazard, probability or average expected rate of experiencing earthquake intensity j, and
[V|H]ij the vulnerability, the level of loss that would be causedto element i given Hazard j (ie, as a result of experiencing earthquake shaking of severity j)
Earthquake Risk - 2
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Risk Assessment
0.0001
0.001
0.01
0.1
1
5 6 7 8 9 10 11
MMI
Pro
b o
f E
xcee
dan
ce p
a
0.0%
20.0%
40.0%
60.0%
80.0%
100.0%
120.0%
Dam
age
Pe pa
Damage | MMI
0.0001
0.001
0.01
0.1
1
5 6 7 8 9 10 11
MMI
Pro
b o
f E
xcee
dan
ce p
a
0.0%
20.0%
40.0%
60.0%
80.0%
100.0%
120.0%
Dam
age
Pe pa
Damage | MMI
Example
A site’s seismicity is equivalent to MMI every 10 years, MMI 7 every 50 years, etc. On the site, a building will experience 0.1% loss given MMI 6, etc, see Table and graph.
Due to the range of seismicity, the average loss per year is 0.28%, as shown in the Table
MMI Pe pa pdf pa Damage | MMI Damage6 0.1 0.08 0.1% 0.000087 0.02 0.018 10% 0.00188 0.002 0.001 20% 0.00029 0.001 0.0005 50% 0.0002510 0.0005 0.0005 100% 0.0005
E(D) = 0.00283
MMI Pe pa pdf pa Damage | MMI Damage6 0.1 0.08 0.1% 0.000087 0.02 0.018 10% 0.00188 0.002 0.001 20% 0.00029 0.001 0.0005 50% 0.0002510 0.0005 0.0005 100% 0.0005
E(D) = 0.00283
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Loss Estimation Software
There are several software programs that can be used to estimate seismic risk. These include: REDAS (Rapid Earthquake Damage Assessment System), PHIVOLCS) HAZUS, available from www.nibs.org RADIUS, available from www.unisdr.org or