2. erakv- 2nd seminar: risk assessment

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


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


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 (cement) 45%

RC Eng. 55%RC Non-Eng. 0%Masonry (cement) 45%



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



→ 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



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



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

2. erakv- 2nd seminar: risk assessment

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