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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