Post on 23-Jan-2018
T H E P R O J E C T F O R A S S E S S M E N T O FE A R T H Q U A K E D I S A S T E R R I S K F O RT H E K A T H M A N D U V A L L E Y I N N E P A L
April 11, 2017
Seismic Risk Assessment forKathmandu Valley
Suman Salike, SDE, MoUDKenpei Kojika, JICA Project Team
CONTENTS
→ Earthquake and Its Consequence→ Procedure of Seismic Risk Assessment→ Scenario Earthquake and Seismic Hazard→ Building Damage→ Damage of Infrastructure and Lifeline→ Human Casualty→ Economic Loss→ Conclusions
2
→ Earthquake and Its Consequence
3
How an Earthquake Happens
Elastic Rebound Theory4
Fault
Where the Earthquake Happens
Antarctic plate
African plate
South American plate
Indian plate
Eurasian plate
Philippine sea plate
Pacific plate
North American plate
Plate Boundary or Fault inside Plate
Source of Gorkha Earthquake (from S. Wesnousky, et.al.)5
Characteristics of the Earthquake
X 31.6X 1000X
Magnitude and Intensity Distribution of Gorkha Earthquake (from USGS)
Difference of Magnitude and its energy 6
Magnitude describes the energy released by an earthquake (e.g. Richter scale)
Intensity gives the information of ground shaking strength and related to damage degree, changing with the distance from the site to the source of earthquake (e.g. MMI)
M=7.8
VIIIVII
VI
Diversity of Earthquake Consequence
Building Damage
Fire
Landslide
Tsunami
Liquefaction
7
→ Procedure of Seismic Risk Assessment
8
Hazard:A dangerous phenomenon, substance, human activity or condition that may cause loss of life, injury or other health impacts, property damage, loss of livelihoods and services, social and economic disruption, or environmental damage
Vulnerability:The characteristics and circumstances of a community, system or asset that make it susceptible to the damaging effects of a hazard
Definition of Disaster Risk
Exposure:People, property, systems, or other elements present in hazard zones that are thereby subject to potential losses
Disaster risk = Hazard * Vulnerability * Exposure
RISK
HazardExposure
Vulnerability
Hazard, exposure, vulnerability and disaster risk (According to ISDR)
9
Law, Regulation
Avo
idan
ce
Sustainable Development
Components of Disaster Risk Management
10
We Are Here
Approach of Seismic Hazard and Risk Assessment
Earthquake Source
Site response
Attenuation
Total risk is determined by the intensity of ground motion, vulnerability of structure and the number of vulnerable structures 11
Target of Seismic Risk Assessment
Building Road Bridge
Water & Sewage Power & Communication Human and Economic Loss
12
→ Scenario Earthquake and Seismic Hazard
13
Scenario Earthquakes
Thomas Ader et al. 2012 J. R. Elliote et al. 2016
2015 Gorkha Earthquake
14
(1) Far-Mid Western Nepal
M=8.6
(2) WesternNepal
(3) Central Nepal South
M=7.8M=7.8 1934 Bihar Earthquake
Ground Shaking Level for Risk Assessment
15
Gorkha Earthquake
Scenario Earthquake Fault Model
(1)
(2)(3)
CNS-2/CNS-1 ≅ 1.5CNS-3/CNS-1 ≅ 2.0
Peak Ground Acceleration (PGA) Distribution
Case WN
Case CNS-1 Case CNS-2 Case CNS-3
Gorkha earthquake(estimated for verification)
16
150 - 200
150 - 400
150 - 200
300 - 800250 - 600
Intensity (MMI) Distribution
Case WN
Case CNS-1 Case CNS-2 Case CNS-3
17
Gorkha earthquake(estimated for verification)
Liquefaction Distribution
Case WN Case CNS-1 Case CNS-2 Case CNS-3
18
Case WN Case CNS-1 Case CNS-2 Case CNS-3
Rainy Season
High potentialModerate potentialLow potential
Dry Season
Note: Due to soil properties are insufficient, some assumption are made for the liquefaction estimation
Slope Failure Distribution
Case WN
Case CNS-1 Case CNS-2 Case CNS-3
19
Note: Due to soil properties are insufficient, some assumption are
made for the slope failure estimation→ Building Damage
20
Damage of Gorkha Earthquake
Kathmandu Durbar Square (2015/5/6)
Bhaktapur (2015/5/7)
Gongabu (2015/5/23)
Sankhu (2017/3/24)Sankhu (2015/5/23)
Gongabu (2017/3/24)
21
NowImmediately after earthquake Masonry RC buildingLevel 1: Negligible to slight damageNo structural damage, slight non-structural damage)
Level 2: Moderate damageSlight structural damage, moderate non-structural damage
Level 3: Substantial to heavy damageModerate structural damage, heavy non-structural damage
Level 4: Very heavy damageHeavy structural damage, very heavy non-structural damage
Level 5: DestructionVery heavy structural damage, collapse of ground floor or parts of buildings.
Building Damage Level
European Macroseismic Scale (EMS) 199822
Procedure of Building Damage AssessmentDamage Function
Building Damage
Ground Shaking (PGA)∑ Building
23
Ground Shaking (PGA)
Dam
age
Ratio
Building Structure
DL4+5
DL3+4+5
DL2+3+4+5
Proposed Damage Function
Category Structural type1 Masonry 1 Adobe2 Masonry 2 Brick masonry with mud mortar,
flex roof & 20 years and moreStone with mud mortar
3 Masonry 3 Brick masonry with mud mortar, rigid roof, &flex roof within 1~20 years
4 Masonry 4 Brick masonry with cement mortar Stone with cement mortar
5 RC 1 RC non-engineered6 RC 2 RC engineered with low to mid-rise
Six structure types for center and perimeter areas, respectively
24
0%
20%
40%
60%
80%
100%
0 200 400 600 800
Masonry 1 Masonry 2 Masonry 3
Peak ground acceleration (PGA: cm/sec2, gal)
Dam
age
Gra
de4+
5
0%
20%
40%
60%
80%
100%
0 200 400 600 800
Masonry 1p Masonry 2p Masonry 3pMasonry 4p RC 1p RC 2p
Peak ground acceleration (PGA: cm/sec2, gal)
Dam
age
Gra
de4+
5
Perimeter area of the Valley Center area of the Valley
predominant period Tg > 1.5s predominant period 0.3s < Tg < 1.5s
1 2 3 4 5 6 1 2 3 4 5 6
Estimation of Building Inventory in 2015
Total Number: 444,554 25
Entire Building Inventory Survey in 4 MunicipalitiesSampling Building Survey (More than 10,000 Buildings in study area)Interpretation of Building Footprint using High Resolution Satellite ImageThe Urbanization Pattern analysis, Land use mapping, etc
Component Ratio of Building Types Building Number
Estimation of Baseline Inventory for Risk Assessment
Assumption: Heavily damaged buildings (GD4+5) due to Gorkha Earquake were supposed to be reconstructued with Brick Masonry with Cement or RC-Engineered.
Total Number: 444,554
26
RC Non-eng. to RC Eng.: 1%B/S with mud to B/S with cement : 5%Adobe to B/S with cement : 2%
Baseline inventory
Total Number: 444,554
Building Damage Distribution for Baseline Inventory
27
Building Damage Distribution
Building Damage Ratio Distribution
CNS-2CNS-2
Building Damage Estimation (Baseline inventory)
28
Heavy, Moderate and Slight Damage Building
School Building Damage Estimation
29Damage Distribution (CNS-2)
Scenario Earthquake
Damage LevelTotal (5,731)
DL2 DL3 DL 4 & 5WN 568 253 237 1,058 18.5%CNS-1 916 539 737 2,192 38.2%CNS-2 1,057 810 1,654 3,521 61.4%
CNS-3 960 875 2,486 4,321 75.4%
Damage by Structure Type
Health Facility Building Damage Estimation
30Damage Distribution (CNS-2) Damage by Structure Type
Scenario Earthquake
Damage LevelTotal (584)
DL2 DL3 DL 4 & 5WN 51 24 20 95 16.3%CNS-1 85 55 64 204 34.9%CNS-2 105 83 153 341 58.4%
CNS-3 97 94 235 426 72.9%
Government Building Damage Estimation
31
Scenario Earthquake
Damage LevelTotal (478)
DL2 DL3 DL 4 & 5WN 44 20 20 84 17.6%CNS-1 71 44 59 174 36.4%CNS-2 85 66 126 277 57.9%
CNS-3 80 73 186 339 70.9%
Damage Distribution (CNS-2) Damage by Structure Type
Building Inventory Assumption for 2030
RC Eng. 7%RC Non-Eng. 48%Masonry (all) 45%
RC Eng. 20%RC Non-Eng. 35%Masonry (all) 45%
RC Eng. 20%RC Non-Eng. 35%Masonry (cement) 45%
RC Eng. 55%RC Non-Eng. 0%Masonry (cement) 45%
RC Eng. 53%RC Non-Eng. 24%Masonry (all) 23%
RC Eng. 69%RC Non-Eng. 17%Masonry (all) 14%
Case 0, same as 2016
Case 3 Case 4 Case 5
Case 2Case 1
32
Bldg. at 2016: 444,554Bldg. at 2030: 606,506(New bldg.: 161,592)
Building Damage Estimation (2030)
33
Cost: 57,335/year mil. NPRCost: 231,931/year mil. NPR
Cost: 172,761/year mil. NPR
Cost: 209,210/year mil. NPR
Cost: 72,702/year mil. NPR
→ Damage of Infrastructure and LifelineRoadBridgeWater Supply PipelinePower Distribution NetworkTelecom Network (BTS)
34
Road
35
Hazardous Road Segment of Road Network
Potential area of Landslide
Potential area of Landslide
Potential area of Liquefaction
Potential area of Liquefaction
Road NetworkRoad Network
Hazardous road segment is identified by comparing the road network with the potential landslide and liquefaction sites
36
Possible road damage by Liquefaction
Possible road damage by landslide
Road-link Blockage by Building Damage in Kobe Earthquake
37
Width of representative road: Less than 3.5mRate of road-link blockage (%)=0.9009×Rate of damaged building(%)+19.845
Width of representative road: 3.5m to < 5.5mRate of road-link blockage (%)= 0.3514 ×Rate of damaged building(%)+13.189
Width of representative road: 5.5m to < 13mRate of road-link blockage (%)= 0.2229 ×Rate of damaged building(%) -1.5026
(Source: Central Disaster Prevention Council, Japan)
Hazardous Road Segment (CNS-2)
38
By landslide
98.5 km1.7%
274.9 km4.7%
Blockage of emergency roadBy blockage
By liquefaction
Bridge
39
Main Mode of Bridge Damage
40
Bridge Fallhttp://www.ktr.mlit.go.jp
http://www.city.yokohama.lg.jp
Shear Failure of Pier
Bending Failure of Pierhttps://www.hanshin-exp.co.jp
Bridge Inventory
41
62 bridges from DOR bridge database83 bridges from project surveyTotal 145 bridgesSingle-span bridges: 73Multi-span bridges: 72
RC pier: 45 for EvaluationOthers: 27
Bridge Damage Estimation
42
Damage WN CNS-1 CNS-2 CNS-3Heavy 0 1 12 32Moderate 2 21 27 11Slight 18 17 6 2
Water Supply Pipeline
43
Procedure of Damage Estimation for Pipeline
PGA (gal)Seismic Intensity (MMI)Liquefaction Potential
Calculation of Damage Rate by each Grid
Pipe Line Damage Rate(Damage Spot / Km)
Pipeline
Seismic HazardSeismic Hazard
Water Supply Network
Water Supply Network
44
45
Water Supply Pipeline Network
Existing Network Planned Network (under construction)
46
Damage Estimation of Water Supply Pipeline
Existing Network Planned Network (under construction)
Damage WN CNS-1 CNS-2 CNS-3spot 982 1,921 3,496 5,161 spot/km 0.84 1.65 3.00 4.42
Damage WN CNS-1 CNS-2 CNS-3spot 124 255 460 676 spot/km 0.18 0.36 0.66 0.97
Power Distribution Network
47
Power Pole
Seismic HazardSeismic Hazard
Building Damage Ratio Building Damage Ratio
Procedure of Damage Estimation for Power Network
48
Number of Power Pole Damage
ElectricityNetwork
ElectricityNetwork
Pole Failure Rate due to seismic shaking[%]
Pole Failure Rate due to seismic shaking[%]
Pole Failure Rate due to building collapse [%]
Pole Failure Rate due to building collapse [%]
Damage Assessment Procedure for Power Pole
Estimation of Power Pole Damage
49Total number of poles in KV : 190,851
Damage WN CNS-1 CNS-2 CNS-3No. of pole 1,327 3,991 9,156 13,992
Ratio 0.7% 2.1% 4.8% 7.3%
Telecom Network (BTS)
50
Damage Estimation Method for Rooftop BTS Tower
51
Ground Shaking
No damageDamage
No damageDamage No damageDamage
Not FunctionNot
FunctionFunction
Not Function
Damage Estimation of Rooftop BTS Tower
52
Damage WN CNS-1 CNS-2 CNS-3No. of BTS 43 143 372 601
Ratio 4.1% 13.7% 35.7% 57.6%
Total number of BTS tower : 1,043
→ Human Casualty
53
Procedure of Human Casualty Estimation
PGAdistribution
Buildinginventory
Buildingdamage
Number of death
Number of injured
Injured Rate
Scenarioearthquakes
Damagefunction
Populationdistribution
Death Rate
54
Earthquake Occurrence Scenes
2016 Daytime (12:00)Weekday
Night (2:00)
Weekend Daytime (18:00)
WeekdayWeekend
Inside Bldg. : 70%
Inside Bldg. : 100%
Inside Bldg. : 90%
Scene Features of Damage
NightMore human casualty occurDifficult for speedily evacuation, especially in winter or rainy season, which may enlarge human casualty
Weekday Daytime
More human casualty happen in office and commercial facilities, rather than in homeA large number of people who have to stay in office, commercial facilities due to transportation problem
Weekend Daytime
Minimum number of human casualty than the other scenesMay cause delay on search and rescue due to the difficulty of personnel mobilization 55
Results of Death Estimation
56
Scenario Earthquake
Earthquake Occurrence Scene
Weekend (18:00) Weekday (12:00) Night
WN 2,123 0.08% 2,784 0.10% 3,034 0.11%CNS-1 6,393 0.23% 8,282 0.30% 9,133 0.33%
CNS-2 15,526 0.56% 19,959 0.72% 22,179 0.80%
CNS-3 25,008 0.90% 31,956 1.15% 35,726 1.28%
Total population: 2,786,929
Results of Injured Estimation
57
Scenario Earthquake
Earthquake Occurrence Scene
Weekend (18:00) Weekday (12:00) Night
WN 8,316 0.30% 10,905 0.39% 11,880 0.43%CNS-1 25,036 0.90% 32,435 1.16% 35,766 1.28%
CNS-2 60,803 2.18% 78,168 2.80% 86,861 3.12%
CNS-3 97,940 3.51% 125,152 4.49% 139,914 5.02%
Results of Evacuee Estimation
58
Scenario Earthquake
Earthquake Occurrence Scene
Weekend (18:00) Weekday (12:00) Night
WN 279,942 10.0% 285,850 10.3% 279,031 10.0%CNS-1 645,483 23.2% 652,798 23.4% 642,743 23.1%
CNS-2 1,202,734 43.2% 1,206,530 43.3% 1,196,080 42.9%
CNS-3 1,624,032 58.3% 1,619,792 58.1% 1,613,314 57.9%
Death Distribution (CNS-1, Night)
59
Death Distribution Death Ratio Distribution
Human Casualty due to School Building Damage
60
→ Economic Loss
61
Coverage Sectors for Economic Loss Estimation
Direct damage Indirect damage
Tourism
Agriculture
Small and medium-size enterprise (SME)
Commerce
Building Road Bridge
Water supply Power CommunicationQuantitative Evaluation
62
Note: Quantitative evaluation of indirect loss is difficult because the correlation of indirectloss cannot be evaluated definitely, thus indirect loss is principally conducted by qualitativeevaluation. As the tourism sector is an important source of foreign exchange earnings, thedecreased amount of production in tourism sector due to the retarded production activitiesfrom earthquake damage is evaluated quantitatively.
Direct Loss Due to Building Damage
Unit: Million NPR
63
Scenario Ground Motion
AllBuilding School Government
buildingHealth Facility
HistoricalArchitecture
CNS-3 1,098.353 134,932 22,708 232,782 2,377
CNS-2 761,531 98,171 16,514 165,683 2,267
CNS-1 371,003 51,231 8,669 68,588 1,925
WN 132,999 20,462 2,444 22,534 1,321
Remarks: Director loss of all building includes that of school, government building and health facility.
Direct Loss of Infrastructure and LifelineUnit: Million NPR
52.2% 34.7%51.9%
64
Scenario Ground Motion
Road Bridge Water Supply Sewage Power
DistributionMobile
BTS Total
CNS-32,878 1,914 191 290 197 1,142 6,612
43.5% 28.9% 2.9% 4.4% 3.0% 17.3% 100.0%
CNS-21,620 1,359 129 200 129 707 4,144
39.1% 32.8% 3.1% 4.8% 3.1% 17.1% 100.0%
CNS-1471 898 71 135 56 272 1903
24.8% 47.2% 3.7% 7.1% 2.9% 14.3% 100.0%
WN0 377 36 76 19 82 590
0.0% 63.9% 6.1% 12.9% 3.2% 13.9% 100.0%
Direct Loss of Building & Infrastructure
99.6%
99.5%
Unit: Million NPR
0 200,000 400,000 600,000 800,000 1,000,000 1,200,000
WN
CNS-1
CNS-2
CNS-3
BuildingInfrastructure
99.5%
99.5%
99.4%
1,104,965
765,675
99.6%
371,275
133,589
65
Procedure for Indirect Loss
Occurrence ofan earthquake
Decline in
Tourists
Job loss in
Tourism sector
Decline of tourist spending
Decline of Foreign
exchange earning
Decline of
GDP
66
Decline of Number of Tourists
67
0
100,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
900,000WNCNS-1CNS-2CNS-3
400,000
640,000
560,000
480,000
440,000
640,000
560,000
480,000
440,000
Before Earthquake
After Earthquake(within 1 year)
After Earthquake(after 12 months~within 24 months)
After Earthquake(after 24 months~within 36 months)
800,000
480,000
320,000
280,000
Unit: Tourists
Note: Estimated based on the tourism stats of Nepal
Impact on GDP by Tourist Sector
Note: Estimated based on the data of Ministry of culture, Tourism & Aviation68
2,120 2,120 2,120 2,120
2,075 2,066
2,059 2,055
2,020
2,040
2,060
2,080
2,100
2,120
2,140
WN CNS-1 CNS-2 CNS-3
Before EarthquakeAfter Earthquake2.15% decrease
2.53% decrease2.88% decrease
3.09% decrease
Unit: Billion NPR
Remarks: This impact for GDP does not include the impact due to other industry exceptfor tourism industry , therefore actual impact for GDP is estimated bigger than this estimation.
→ Conclusions
69
Damage Characteristics of Scenario EarthquakesCentral Nepal south scenario earthquake will damage morethan Gorkha earthquake.Large number of buildings in KV are highly vulnerable,including school, hospital and government buildings.Risk of building damage and human casualty will beincreased in future if no measure is taken to strengthenbuilding seismic performance.Although infrastructure and lifeline system had no significantdamage in Gorkha earthquake, there will be more damageswhen strong earthquake happens.The new water supply network (under construction)significantly reduces the risk with respect to the existing one.The majority of the damage of rooftop BTS will be by thebuilding damage.
70
Utilization of Risk Assessment Results in this Project
The risk assessment results will be utilized for the municipaldisaster risk reduction and management plan for the threepilot municipalities within this project and could be used forthe same purpose for the whole KV.
The risk assessment results provide basic information fordetermining the risk reduction target based on the timespan and available budget, technology, etc.
The results of human casualty provide the usefulinformation on the stockpiling of water, food, emergencymaterials as well as securing the evacuation routes andspaces.
71
RecommendationsResults of risk assessment depends largely on results ofseismic hazard.
Three ground motion levels of Central Nepal South (CNS)Scenario Earthquake were targeted for risk assessmentdue to the uncertainties in the estimation of futureground motion. Further research on Gorkha earthquakeis necessary. Should be updated for new findings.
Building inventory for whole KV is not existed and data forinfrastructure and lifeline networks is not completelymaintained.
Development and its regular updating of GIS database ofbuildings, infrastructure and lifeline network is veryimportant for the development of disaster risk reductionand management plan and routine maintenance works.
72
Recommendations (cont.)Large number of buildings, including school, health facilitiesand government buildings, are estimated to suffer heavydamage for the scenario earthquakes. Strengthening ofbuildings is a big issue for both new and existing buildings.NBC, specially NBC 105, has to be revised.Enforce NBC for all new buildingsPromotion of seismic strengthening of existing buildings, via.retrofitting or reconstruction through policy, legal means,budget arrangement, technology development as well aspublic awareness.For seismic risk reduction, risk assessment for whole Nepal is considered necessary. Has to be started immediately for other Metro city like Pokhara, Chitwan, etc.Based on the risk assessment results, the governmentorganizations and utility companies could make their BusinessContinuity Plan (BCP). 73