Disclaimer
This report was compiled by an ADRC visiting researcher (VR) from ADRC
member countries.
The views expressed in the report do not necessarily reflect the views of theADRC. The boundaries and names shown and the designations used on themaps in the report also do not imply official endorsement or acceptance by theADRC.

ASIAN DISASTER REDUCTION CENTER ( ADRC )MONEER ABDULLAH AL-MASNISEISMOLOGICAL AND VOLCANOLOGICALOBSERVATORY CENTER (SVOC)

OUTLINE OF PRESENTATIONGeneral Information
Brief description of National Seismic Network.
Disaster Profile in Yemen.
Yemen Disaster Management System.
Research Action Plan

GENERAL INFORMATION
Topography
The country’s
topography ofRugged
Mountains,
Volcanic
Highlands,
Deserts, andCoastal plains.
plains.

Geo-Tectonic
Geosetting

OMAN

SAUDI
ARABIARed

Location:

SEA

GULF OF ADEN

Yemen is located in thesouthern west of the
Arabian peninsula.
(Arabian plate)is bordered byactive seismiczone : the Red
Sea from thewest and Gulf ofAden from thesouth..

AREA :

528,000 km², 21
GovernoratePOPULATION:
22 million.

GENERAL INFORMATION

Sana’a city

Bottle Trees、、 Socotra Island

Aden

Brother Blood Trees 、Socotra Island

ORGANIZATIONSTRUCTURE

Ministry of Oil and Minerals
GEOLOGICAL SURVEY & MINERALRESOURCES BOARD

SEISMOLOGICAL AND
VOLCANOLOGICALOBSERVATORY CENTER

DEPARTMENT OF
EARTHQUAKEENGINEERINGDEPARMENT OF
EARTHQUAKEMONITORINGDEPARMENT OF FINANCIAL AND
ADMINISTRATION AFFAIRSDisaster mitigation

National Digital
Network

Strong motion Network

Telemetry Network

Geophysics

Maintenance

Data Bank

Yemen Seismic Network
Yemen
Red

Strong motion stations

Sea

Gulf of Aden

Yemen
RedSeaShort period stations
Gulf of Aden

Broad band stations

GIS ,SPATIAL DISTRIBUTION OF DISASTERS IN YEMEN

EXAMPLES OF MAJOR DISASTERS IN YEMEN

Dhamar Earthquake••••••

December 13,1982
Magnitude: 6.0
Depth: 7km
Economic losses: 2$ billion
Homeless: 250,000
Deaths: 2800
Injured : 15000

RedSeaYemen
RedSeaDhamarGulf of Aden

Landslides at Al-Dafir
2005 (killed 65 person)

Earth fissures ,Jahran Basin,2006

Volcanic Eruption
at Al-Tair Island,2007( Killed 6 persons)

Hadramut Flood,2008 (Killed 73persons)12

A report Prepared for World Bank with GFDRR (Global Facility for Disaster Reduction and Recovery)
Oct,2010

ResearchAction Plan ForEarthquake Risk Assessment
In Sana’
Sana’a City13

Seismic Mitigation is a Cycle

Immediately after an earthquake

Risk Reduction:

Preparedness:

Activities to reduce the impact of an earthquake beforestrikes•Strengthening existing structures•Implementing seismic building code
•Retrofit of buildings•Planning and training for emergency response
activities•Public awareness raising•Research on earthquakes• establishment of Early warning System

Emergency Response and Relief Actions immediately
after an earthquake•Search and rescue of buried victims•Emergency medical care
•Fire suppression•Shelter for homeless victims•Supplies of food, water, and necessary materials

Rehabilitation and Reconstruction:
Before an earthquake

The long-term process of rebuilding a wholecommunity after an earthquake•Rebuilding houses and buildings•Financing for retrofitting & rebuilding•Repair of roads, bridges, water system, etc.
•Psychological counseling

Long-term after anearthquake
14

Background
Important of Sana’a City


Sana’a basin area : ~ 160 km
km²²

POPULATION: ~ 2 million
Sana’a city is subjected by severalstrong earthquakes occurred in thepast periods.

Recently, peoples in this area feelingby a large shaking ,although , it issmall earthquakes. Due to the effectof the sedimentary basin layers which
acting to amplify the seismic waves.

Generally , Earthquake Damage, islarger over soft sediments than on
firm bedrock outcrops.

M6.0 ~
0742

M5.7 ~
1908

M5.0 ~
1644

Therefore, Earthquake Risk
Reduction on Sana’asedimentary basin isnecessary.

M6.2 ~
1982

15Effects of sedimentary basins

Depth [km]

平野

50100

CrustMantle

at Sedimentary Basins-Amplification inLow-Vs (Soft) sediment-Basin Induced
Surface Waves

150-Energy Trapping
Dr.Furmura , Tokyo institute , Japan

16

Objective of the Project

Earthquake Loss Estimation and Risk
Assessment in Sana’a City

17

METHODOLOGY OF EARTHQUAKE RISK ASSESSMENT

Assessment of the Seismic Risk using the relation:

Seismic Risk = Hazard * Vulnerability
Develop an Earthquake Scenario to estimate anddescribe the (damage) of a probable earthquakeon the city.

18

METHODOLOGY OF EARTHQUAKE RISK ASSESSMENT(Main Process)
Ground Motion =Hazard Assessment (~ Soil Effect Study )(1)

Source+ Path + Site effects
Vulnerability Assessment
Development of Earthquake
Scenario for Damage
Assessment
Urban Disaster Prevention
Planning

(2)

(3)

(4)

Safety & Strengthened City
19

Activity (1(1):

Hazard Assessment (~ Soil Effect Study )Required information :• Estimation of Local Site effects (soil Response )• Soil Amplification.
• Predominant period.
• PGA/MMI.
• S- wave velocity of subsurface structure.

20

Methods of Estimation Site effect(1) H/V spectral ratio(2) Ground Response analysis

Information of underground structure

Numerical Analysis
1D-SHAKE Model
S-wave velocity , Density,Thickness,

Amplification, Stress and strain

Microtremor Survey
Equivalent linear method
21

Example of grid Points

22

Points of H/V method

Points of Array methodDispersion Curve of Rayleigh Wave at EMC_14
Frequency (Hz)SPAC Coefficient

012

34

56

78

9

1.2

10

Observed Velocity

1.2
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6

1

Calculated Velocity

0.8

0.6

0.4

0.2

017.3m

30.0m

34.6m

51.9m

60.0m01234567F r eq uency ( Hz )ρ(ω;r) =1 2π real[SCX(ω;r,θ)]dθ
2π ∫0 SC(ω;0,0)SX (ω;r,θ)S he a r wa v e v e lo c it y pro file be ne a t h s ite N o .14 _ E M CVelocity (m/ sec)
0100200 300

400 500

600 700

800 900 1000 1100 1200 1300

020406080

100

23velo.profile
120

Ground Motion Modeling at surface of study site
Using equivalent linear Method248Output of Hazard Assessment
 Seismic Microzoning Maps:- Soil Amplification zoning Map- Predominant Period zoning Map- PGA Acceleration zoning Map- Seismic Intensity zoning Map- Shear wave Velocity structure profiles- Soil classification Map- Engineering bedrock Map
25

Activity (2):Vulnerability Assessment using GIS

Required information• Characteristics of local buildings (Type, Age, Height, etc.)• Inventory of buildings ( include location of buildings)• Characteristics of local infrastructure.
• Inventory of infrastructure .
• Population information.
• Data on the human and economic impacts of pastearthquakes.
Digital Maps:
Geological Map, Topography map ,Borders map , faults map
Satellite Base Map , seismicity map …. etc

26

Activity (3(3):Damage Assessment

27

Activity (4):Urban Disaster Prevention Planning28

Output of Vulnerability and Damage Assessment

Seismic Risk Distrib.
Distrib. Maps:- Building damage zoning Map.
- Infrastructure Damage zoning Map.
- Casualties zoning Map …etc.
Example : Existing Building Distribution

29

Building Damage Ms 8.0

Existing Electricity Network

Damage of Electricity

30

(Thank you!)31