TSUNAMI CAUSES, RISKS AND

MITIGATION MEASURE FOR

KARACHI

UE-027 UE-031 UE-051 UE-057 UE-058

SUBMITTED BY:

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ABSTRACT

This report is about the study of tsunami, its effects on the humans, infrastructure, environment

and in general the whole nation. This study briefly covers the risk management and crisis

management including the mitigation measures, evacuation and escape plans for tsunami for the

city of Karachi. It also emphasis on importance of such management plans for Karachi.

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Contents INTRODUCTION

CAUSES OF TSUNAMI .................................................................................................................................... 4

Seismic Activity ................................................................................................................................ 4

Submarine Landslides ...................................................................................................................... 6

Cosmic impacts ................................................................................................................................ 6

Volcanic Eruptions ........................................................................................................................... 6

EFFECTS OF TSUNAMI ................................................................................................................................... 7

RISK MANAGEMENT

Why is it necessary for Karachi to take precautions against Tsunami? ................................................ 9

MITIGATION: ............................................................................................................................................... 10

1. Structural Mitigation Measures: ......................................................................................................... 10

2. Non- Structural Mitigation Measures: ................................................................................................ 11

PREPAREDNESS: .......................................................................................................................................... 14

1. EARLY WARNING SYSTEM ............................................................................................................... 14

Tsunami Prediction: ............................................................................................................................ 14

Public Awareness and Education: ....................................................................................................... 14

2. EVACUATION AND ESCAPE ROUTES: .............................................................................................. 15

Evacuation plan: .................................................................................................................................. 15

ESCAPE ROUTES: ................................................................................................................................. 16

.................................................................................................................................................................... 17

CRISIS MANAGEMENT

Response or Rescue .................................................................................................................................... 25

Role of Response Agencies of Karachi .................................................................................................... 25

1. ARMED FORCES. .......................................................................................................................... 25

2. FIRE FIGHTING SERIVCES: ............................................................................................................ 25

3. MISCELLANEOUS EMERGENCIES: ................................................................................................ 25

4. NDMA .......................................................................................................................................... 25

5. PROVINCIAL RELEIF DEPARTMENT: ............................................................................................ 26

6. NGO: ............................................................................................................................................ 26

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7. KESC. ........................................................................................................................................... 26

8. KSWB ........................................................................................................................................... 26

RECOVERY OR RECONSTRUCTION .............................................................................................................. 26

CONCLUSION

REEFERNCES

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INTRODUCTION

Tsunamis are a series of large ocean waves generated by large undersea disturbances, such as a

major earthquake on the sea floor or landslide, volcanic eruption, meteorites and explosions.

Tsunamis are not affected by tides or currents a tsunami in the ocean means the whole water

column is moving, not just the surface and can strike any ocean shoreline.

A tsunami wave in the open ocean can be more than 100 km across. All types of waves

including tsunamis have a wave length, a wave height, and amplitude, a frequency or period,

and a velocity.

Tsunamis have velocities up to 950 km/hr (about as fast as jet airplanes), and thus move much

more rapidly across ocean basins.

Tsunami waves do not resemble normal sea waves, because their wavelength is far longer.

Rather than appearing as a breaking wave, a tsunami may instead initially resemble a rapidly

rising tide, and for this reason they are often referred to as tidal waves. Tsunamis generally

consist of a series of waves with periods ranging from minutes to hours, arriving in a so-called

"wave train". Wave heights of tens of meter can be generated by large events. Although the

impact of tsunamis is limited to coastal areas, their destructive power can be enormous and

they can affect entire ocean basins; the 2004 Indian Ocean tsunami was among the deadliest

natural disasters in human history with over 230,000 people killed in 14 countries bordering the

Indian Ocean.

CAUSES OF TSUNAMI Tsunami is caused by mainly three reasons, seismic activity, submarine landslides and cosmic

impacts.

Seismic Activity

Most tsunamis are caused by earthquakes generated in

a subduction zone, an area where an oceanic plate is being

forced down into the mantle by plate tectonic forces. The

friction between the sub ducting plate and the overriding

plate is enormous. This friction prevents a slow and steady

rate of subduction and instead the two plates become

"stuck".

Figure 1: Oceanic plate and overriding plates

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As the stuck plate continues to descend into the mantle the motion causes a slow distortion of

the overriding plate. The result is an accumulation of energy very similar to the energy stored in

a compressed spring. Energy can accumulate in the overriding plate over a long period of time -

decades or even centuries.

Energy accumulates in the overriding plate until it exceeds the frictional forces between the

two stuck plates. When this happens, the overriding plate snaps back into an unrestrained

position. This sudden motion is the cause of the tsunami - because it gives an enormous shove

to the overlying water. At the same time, inland areas of the overriding plate are suddenly

lowered.

The moving wave begins travelling out from where the

earthquake has occurred. Some of the water travels out

and across the ocean basin, and, at the same time, water

rushes landward to flood the recently lowered shoreline.

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Submarine Landslides Submarine landslides can also cause tsunamis. Submarine landslides occur during

earthquakes and the implosion of underwater volcanoes. The falling sediment and rock in

these landslides can also trigger massive water movement, resulting in a tsunami.

Cosmic impacts Cosmic impacts in the ocean are the least frequent cause of tsunamis. This is similar to

throwing a rock into a pond, except on a much larger scale. When the rock hits the water,

it creates small ripples of water moving away from the point of impact. In a cosmic

impact, these ripples would instead be massive tsunamis, increasing in size as they near

the shore.

Volcanic Eruptions There are two different ways that volcanoes can cause

seismic waves. One possibility is for a land-based volcano

to break down and collapse, forcing large amounts of ash

and debris into the water. This sudden change and

displacement of the water column transfers into kinetic

energy and results in waves. More debris can create a

bigger increase in wave amplitude and number. Tsunamis

can also be induced by submarine volcanoes. These underwater volcanoes can collapse

downwards or spew forth lava heating the surrounding water quickly.

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EFFECTS OF TSUNAMI

The effects of a tsunami are devastating. They are one of the world's worst natural disasters that can hit a country. Tsunami damage is first caused by the immense force of the tidal wave hitting the shoreline. Tsunami flooding then continues to cause damage for several more weeks. The effects of the tsunami on the country during this period range from destruction and damage, death, injury, millions of dollars in financial loss, and long lasting psychological problems for the inhabitants of the region. These effects are shown in the following event tree

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HUMAN

IMPACTS DESTRUCTION AND

DAMAGE

DAMAGE

CROP FIELDS COLLAPSE/DES

TABILIZATION

OF BUILDINGS

DAMAGE TO

ROAD AND

BRIDGES

GENERAL

PROPERTY

DAMAGE

INLAND WATER

INTRUSION

ENVIRONMENT

ECONOMY HARDSHIP

DUE TO COST OF

STABILIZATION OF

DAMAGED

INFRASTRUCTURE

MOBILIZATION

PROBLEM

DISRUPTION

OF SEWAGE

LINES

STREET

FLOODING

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As effects of Destruction and Damage is further classified, similarly effects on Human impacts can be further classified into loss of life, injuries and psychological effects.

Hence, if such disaster can be controlled then it would control the amount of loss of life, property, infrastructure, environment and economy, therefore mitigation measures for controlling the disaster and its effects is very important for any state.

Here our object is to provide mitigation measures, generate evacuation plans and early warning systems with crisis management of Tsunami if it hits our great city Karachi.

FIGURE 2: TSUNAMI OF 2011 IN JAPAN

FIGURE 3: TRUE EXTENT OF TSUNAMI REVEALED

FIGURE 4: TSUNAMI WAVES HITTING THE COAST OF MINAMISOMA

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RISK MANAGEMENT

We must remember that every 5 to 10 years there are chances of big earthquake in Pakistan

either in northern Pakistan or southern Pakistan. We do not have to wait for a tsunami to strike

Karachi and then take precautions but we should take the lesson from the past and start

working together now to avoid tsunami-like disasters.

Disasters cannot be prevented or stopped nor their destructive effects can be controlled but

the effects on human life, property and environment can be minimized and mitigation of risk of

the disaster, hence this minimization of effects of disaster is called risk management. The

process of mitigation includes first to identify the risks and potential effects if Tsunami occurs in

Karachi which is shown in the event tree in fig….

Why is it necessary for Karachi to take precautions against Tsunami?

Pakistan’s coast has hardly any scientifically developed tsunami evacuation plans in the public knowledge. Communities settled along the approximately 1,100km long coast are scantly aware of tsunami risks in their areas. Many would not even imagine that a peacefully subsiding wave may be followed by a mightier one.

Coastal communities, especially those in tiny islands and convoluted creeks, have neither

elevated ground nor enough time to escape the tides and are therefore exposed to the risk of

being interred in a watery grave should a tsunami strike.

The gravity of the risk could be judged from the fact that there are three major faults around

Karachi and along the southern coast of Makran, namely, the Arabian, Eurasian and Indian

plates. These faults are 40 km away from Karachi, the east-west Allah Band fault passes through

the city and a few smaller faults run within the city as well. The Makran Subduction Zone,

having the potential of generating earthquakes, is among the least studied subduction zones in

the world. Normally, an earthquake of over 8.0 on the Richter scale could generate a fatal

tsunami in the area.

Before starting any process to develop risk management plan for Karachi, the risky areas of

Karachi should be identified which would be the most vulnerable to tsunami.

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Risk management of disaster includes two steps, mitigation and preparedness.

MITIGATION: Mitigation means the action of reducing the severity and painfulness of something. So for the

risk management of tsunami, mitigation includes reduction of impact of damage of Tsunami.

This can be categorized in the following categories.

1. Structural mitigation measures

2. Non- structural mitigation measures.

In this report we will restrict ourselves to the highlighted disaster impacts which would greatly affect

Karachi if tsunami occurs.

1. Structural Mitigation Measures: Tsunami walls can be built in front of the populated coastal areas to lessen the impact of

tsunami waves.

Floodgates and channels can be provided to redirect the water from incoming tsunamis.

Buildings should be constructed 2-3m above the high tide level.

Break water can be provided to provide cushion against tsunami hazards.

Figure 5: Map of Karachi. Red circle shows the area most vulnerable to tsunami affects.

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2. Non- Structural Mitigation Measures: School, mosques and other facilities should not be located closer to the coastline than 400m and

preferably 800m in at-risk areas.

Mangroves or green belt should be provided along the coastline because they decrease the

intensity of tsunami waves.

Malaysia Forestry Department estimated that a mangrove belt 100 meters wide with a density

of two to three trees every three meters could have reduced the height [of a tsunami] by 70%,

assuming the wave was created by a 7.5 Richter earthquake. Instead of a wave, the water would

have reached land like a rising flood. Such a green belt would have also reduced the power of

the wave by about 90%.”

Natural obstructions also decrease the intensity of tsunami waves like hills.

Buildings near the coastal area can be displayed the height on the floor so people may know at

what height they are standing whether they should move to an evacuating center or whether

they are safe wherever they are.

One floor of taller building can be reserved as a gathering floor so at a time of tsunami people

can evacuate to that.

TABLE 1: TSUNAMI EFFECTS AND DESIGN SOLUTIONS

PHENOMENON EFFECT DESIGN SOLUTION

Inundation

Flooded basements.

Flooding of lower floors.

Fouling of mechanical, electrical and communication systems and equipment.

Damage to building materials, furnishings, and contents (supplies, inventories, personal property).

Contamination of affected area with waterborne pollutants.

Choose sites at higher elevations.

Raise the building above the flood elevation.

Do not store or install vital material and equipment on floors or basements lying below tsunami inundation levels.

Protect hazardous material storage facilities that must remain in tsunami hazard areas.

Locate mechanical systems and equipment at higher locations in the building.

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Use concrete and steel for portions of the building subject to inundation.

Evaluate bearing capacity of soil in a saturated condition.

Hydrostatic forces (pressure on walls caused by variations in water depth on opposite sides).

Elevate buildings above flood level.

Anchor buildings to foundations.

Provide adequate openings to allow water to reach equal heights inside and outside of buildings.

Design for static water pressure on walls.

Buoyancy (flotation or uplift forces caused by buoyancy).

Elevate buildings

Anchor buildings to foundations.

Saturation of soil causing slope instability and/or loss of bearing capacity.

Evaluate bearing capacity and shear strength of soils that support building foundations and embankment slopes under conditions of saturation.

Avoid slopes or provide setback from slopes that may be destabilized when inundated.

Currents

Hydrodynamic forces (pushing forces caused by the leading edge of the wave on the

Elevate buildings.

Design for dynamic water forces on walls and building

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building and the drag caused by flow around the building and overturning forces that result).

elements. Anchor building to

foundations.

Debris impact

Elevate buildings. Design for impact

loads.

Scour

Use deep piles or piers.

Protect against scour around foundations.

Wave break and bore

Hydrodynamic forces

Design for breaking wave forces.

Debris Impact

Elevate buildings.

Design for impact loads.

Scour

Design for scour and erosion of the soil around foundations and piers.

DRAWDOWN

Embankment instability

Design waterfront walls and bulkheads to resist saturated soils without water in front.

Provide adequate drainage.

Scour

Design for scour and erosion of the soil around foundations and piers.

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FIRE

Waterborne flammable materials and ignition sources in buildings.

Use fire-resistant materials.

Locate flammable material storage outside of high-hazard areas.

PREPAREDNESS: Preparedness includes the process of creating awareness among the people and making evacuation and

escape route plans for Karachi.

By educating the public about the tsunami hazard, communities become informed and empowered

to take actions that prepare them for tsunamis. People are taught to recognize the warning signs of

an impending tsunami. They can also plan and maintain escape routes to higher ground, and discuss

ways to assist children and persons with limited mobility. In remote areas there may be no

mechanism to receive advance warning of a tsunami. In situations like these, public awareness of

hazard warning signs and preparedness can save lives.

Preparedness includes the following steps;

1. Early Warning System

2. Evacuation and escape route plan.

1. EARLY WARNING SYSTEM A tsunami warning system (TWS) is used to detect tsunamis in advance and issue warnings to

prevent loss of life and damage. It is made up of two equally important components: a network of

sensors to detect tsunamis and a communications infrastructure to issue timely alarms to permit

evacuation of the coastal areas.

Tsunami Prediction:

Tsunamis can be predicted by using Float Type Gauges. Hydrostatic pressure waves, intensity and arrival

time of tsunami can be predicted through gauge stations. When tsunami is predicted then measures are

taken to avoid destruction and loss of life, that’s why early warning systems are created to create

awareness people.

Public Awareness and Education:

The best warning of the approach of a tsunami following a large local earthquake is the earthquake itself. Should a strong earthquake be felt at medium strength for what seems to be a long period, coastal people should prepare for a tsunami. The tsunami may follow immediately after the earthquake, or up to about an hour later. Sometimes, the first

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indication of the tsunami is the sea receding from the shore, exposing normally covered coral reefs. The rise in sea level then follows.

Hazard awareness and education programs that make scientifically credible information understandable and available, and that are consistent and persistent in delivery of information prove most effective. Several successful educational activities include:

Presentations, lectures, and informal talks offered by local experts that describe the tsunami hazard, identify risk areas, and recommend safety precautions. The Nazims of the tsunami prone towns and areas like Clifton and DHA shall be invited to attend such lectures so that funds could be provided for early evacuation plans and strategies.

As tsunami approach the shoreline, the sea level may, but not always, recede/drop dramatically before returning as a fast-moving wall of water.

Official warnings are only possible for distant and regional source tsunami. Official warnings are disseminated by the National Disaster Management Authority to the national media, local authorities and other key response agencies. The local council may also issue warnings through local media, siren and other local arrangements.

2. EVACUATION AND ESCAPE ROUTES:

Evacuation plan:

A tsunami evacuation plan (TEP) is a plan that will be invoked if a tsunami alarm has been triggered.

Hence a TEP will affect a variety of preparedness measures to be activated in the case of tsunami alert.

The purpose of a TEP is to save the life of those persons that might be affected by the incoming tsunami

waves. Primary aim of a tsunami evacuation plan should therefore be to guide all affected persons along

the evacuation routes

a) Towards safe places (which are supposed to be outside the reach of tsunami waves), also called

assembly facilities or emergency shelters;

b) In time (time span between alarm and arrival of first wave taking into account for each person the

distance to the next emergency shelter).

In addition, an evacuation plan should foresee that a single assembly facility that matches criteria can

cope with the expected number of persons that are supposed to use this assembly facility.

Consequently a TEP is generated on the basis of the following parameters:

number of people affected (including special handicaps like young, disabled or elderly) per

location,

Locations, roads and distances, the accessibility of these, the safety of these after a preceding

earthquake.

Basic assumption on maximal expected wave height.

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Basic assumption on time lap until arrival of first wave.

Practice of evacuation planning:

The existence of a TEP is crucial for evacuation and life‐saving measures. A trend towards the use of

existing and the construction of (artificial) vertical shelter buildings can be used. Signboards should be

provided for the direction to escape, the distance to the next shelter, and the name of the shelter, sign

boards should be written in English and Urdu.

Most of the evacuation preparedness is done through the work of voluntary rescue or disaster

preparedness organizations.

Also we can issue leaflets that contain town/city maps showing the hazard zones, the evacuation routes

and evacuation shelters. Very often additional locations can be marked, such as schools, hospitals,

police and fire departments.

Brochures are printed on two pages and can be folded twice thus producing a handy leaflet which can

be brought elsewhere or which can be put on frequently accessed locations. Typically, a leaflet describes

the hazard, very often with a relationship to a felt earthquake. The brochures contain the evacuation

signs used in that area as well as contact points in order to obtain further information.

Tsunami evacuation maps for all major localities should be located in the front of telephone white page

ESCAPE ROUTES

ESCAPE ROUTES:

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The escape route from Clifton to Mehmoodad is 7.5 km and by car it would take 17 minutes.

CLIFTON

MEHMOODABAD

FIGURE 6: ROUTE 1 FROM CLIFTON TO MEHMOODABAD

CLIFTON

MEHMOODABAD

FIGURE 7: ROUTE 2 FROM CLIFTON TO MEHMOODABAD

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Route 2 from Clifton to Mehmoodabad is of 9.6km and by car takes 19 minutes.

CLIFTON

MEHMOODABAD

Figure 8: Route 3 from Clifton to Mehmoodabad

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Route 3 from Clifton to Mehmoodabad is of 10.5 km and by care takes 20 minutes.

Figure 9: Route 4 from DHA to Mehmoodabad

DHA

MEHMOODABAD

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Route 4 shows the route from DHA to Mehmoodabad with pedestrian taking time 1hour and 19

minutes.

R

oute 1 from Clifton to sadder town is of 4.5 km and by car takes 10 minutes.

CLIFTON

SADDAR

TOWN FIGURE 10: ROUTE 1 FROM CLIFTON TO SADDAR TOWN

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Figure 11: Clifton to Saddar town

Route 1 from Clifton to Sadder town is of 4.4 km and pedestrians might taking 54 minutes.

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Figure 12: Route 5 from DHA to Gulshan-e-iqbal

Route 5 is of 26.4 km and car might take 38 minutes.

DHA

GULSHAN-

E- IQBAL

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Figure 13: Route 7 from DHA to Gulshan-e-iqbal

Route 7 from DHA to Gulshan-e-iqbal is of 24 km and by car will take 38 minutes.

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Figure 14: Route 8 from DHA to Gulshan-e-Iqbal

Route 8 from DHA to Gulshan-e-iqbal is of 21.3 km and pedestrians might take 4 hours and 25

minutes.

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CRISIS MANAGEMENT

Crisis management is the management of the tsunami effects and impacts after it has passed. It involves two phases, response or rescue and recovery or reconstruction.

Response or Rescue This is the period that immediately follows the occurrence of disaster in a way all individual response to disaster but in their own way, this phase includes the mobilization of necessary emergency services and first responders in disaster area such as fire fighters, police and ambulance crews. In addition, volunteers and NGOs may provide practical assistance in terms of food, medicine and temporary shelters.

Role of Response Agencies of Karachi

1. ARMED FORCES.

Law and order situations are handled by Sindh Rangers (para-military force) and Police. Army is

called in to provide relief through massive air and ground efforts. So, if tsunami strikes Karachi

then these armed forces will work with the civil administration in rescue and relief of the

tsunami survivors.

2. FIRE FIGHTING SERIVCES:

Emergency response with regards to fire hazards and medical emergencies will be responded to

by the Fire Fighting Services and ambulance services for the tsunami victims.

3. MISCELLANEOUS EMERGENCIES:

CDGK emergency response services respond to most emergencies, various autonomous

entities like Pakistan Steel Mills, Civil Aviation Authority, Port Authorities and Cantonment areas

maintain their own emergency response services which can be called upon to respond to larger

emergencies.

4. NDMA

NDMA is responsible for issuing national wide alert based on PMD’s input. PMD is responsible

for tsunami early warning and for this purpose besides relying on its own monitoring of tsunami

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weather systems that can possibly impact Pakistan; it also draws from the inputs of WMO

regional cyclone weather monitoring and by Joint Typhoon Warning System USA.

5. PROVINCIAL RELEIF DEPARTMENT:

This department will cope with the funds needed for the rescue and relief of the victims as per

rate of compensation of casualities, houses, and crop damages proposed by provincial technical

committees headed by relief commissioner.

6. NGO:

These agencies will work for relief operation and provide relief services to sustain life, reduce

physical and emotional distress and promote recovery of disaster victims.

7. KESC.

Provide essential electricity required to support relief operations.

8. KSWB

KSWB to accord priority to restoration of potable water in priority worst hit areas.

RECOVERY OR RECONSTRUCTION When the immediate needs of population are met, all medical help has arrived and people have settled

from hustle bustle of the event, they begun to enter the next phase which is called recovery phase is

terms of long term outcome. It is now they perceive the meaning of disaster, loss they have suffered.

The aim of recovery phase is to restore the affected area to its previous stage.

The reconstruction of the city of Karachi will firstly focus on the basic necessities that would be

destroyed due to tsunami like residential buildings, water sanitation system, water supply and sewage

systems, electrical systems and telephone lines specially in the tsunami risk areas like Clifton and DHA.

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CONCLUSION

It is very important for Karachi to prepare beforehand for such destructive and catastrophic disasters

like tsunami. If the mentioned mitigation measures are provided in Karachi, it would be really beneficial

for it. Since, Pakistan is a developing country therefore it does not have much technologies and

resources to implement the techniques used in the developed countries, and moreover, it is necessary

to save our resources and development. Tsunami is such a disastrous event which ruins the whole city

and for developing countries like Pakistan it will get very difficult to manage the system of rescuing and

recuperation, therefore it very necessary to create early warning systems and use prediction techniques

to predict such deadly disasters. If the appointed agencies work on such measures and escape and

evacuation plans for any kind of disaster, Karachi will be able to safe itself and its people.

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REFERENCES

1. http://www.pdc.org/TAK/General/Mitigation/Tsunami_Mitigation_Strategies.pdf

2. http://www.ngi.no/en/Geohazards/Content/Shortcuts/Research-and-development/Prevention-

and-mitigation/

3. http://en.wikipedia.org/wiki/Continental_crust

4. http://en.wikipedia.org/wiki/Subduction

5. http://oceanservice.noaa.gov/facts/tsunami.html

6. http://nthmp.tsunami.gov/taw/downloads/tsunami-factsheet.pdf

7. http://earthsci.org/education/teacher/basicgeol/tsumami/tsunami.html#Howdotsunamisdif

ferfromotherwater

8. http://nidm.gov.in/PDF/safety/flood/link1.pdf

9. http://rickrideshorses.hubpages.com/hub/How-to-survive-a-tsunami-A-guide-to-escaping-a-

natural-disaster