The document discusses tsunamis, their causes, effects, and history. Tsunamis are caused by underwater earthquakes, volcanic eruptions, landslides, or meteor impacts displacing large volumes of water. They have struck coastlines throughout history, including the 2004 Indian Ocean tsunami that killed over 118,000 people across several countries. Early warning systems and evacuation to higher ground can help reduce loss of life from future tsunamis.

1. BY :- Sanjay Shukla

2. What is a tsunami?
• A tsunami is a series of
waves created when water
is moved very quickly.
Underwater earthquakes
are the most common
causes of tsunamis, but
underwater volcanic activity
can also trigger a
displacement in the water,
and create a mega-wave.

4. • First tsunami was recorded in 1480 B.C. in eastern
Mediterranean, when the Minoan civilization was waped
out.
• A large tsunami accompanied by the earthquake of
Lisbon in 1755.
• North and South American records have dated such
events back to 1788 for Alaska and 1562 for Chile. Records
of Hawaiian tsunami go back to 1821.
• Tsunami hits the Mona Passage off Puerto Rico in 1918,
grand banks of Canada in 1929.

5.  Hawaiian tsunami on 1 April 1946 destroyed the city of
Hilo, killing 159 people. Other recent tsunami that have
hit Hawaii are those of 1952,1957,1960,1964 and 1975 .
 Total 65 destructive tsunamis struck Japan between 684
A.D to 1960.
 On 16 August 1976, a large earthquake in the Moro Gulf
in the Philippines generated a destructive local tsunami
which killed over 8,000 persons.
 Last one was Christmas tsunami in 2004.

6.  Volcanic eruptions
 Icefalls
 Heavy rainfall
 Earthquake
 Submarine landslides
 Cosmic impacts
 Meteoroid

7. • Volcanic eruptions and icefalls create
disturbance in water and generate
tsunami.
• Heavy rainfall cause overflow of
water and generate tsunamis.

8. .Tsunami can be generated when the see
floor abruptly deforms and vertically
displaces the overlying water.
.Tectonic earthquakes are a particular
kind of earthquake that are associated
with the earth’s crustal deformation,
when these earthquakes occur
beneath the see, the water above the
deformed area is displayed from its
equilibrium position.
.Waves are formed as the displaced
water mass, which acts under the
influence of gravity, attempts to regain
its equilibrium

9. • Ocean waves are normally divided into 3
groups, characterized by depth:
• • Deep water
• • Intermediate water
• • Shallow water
• Even though a tsunami is generated in
deep water (around 4000 m below mean
sea level), tsunami waves are considered
shallow-water waves. As the tsunami
wave approaches the shallow waters of
shore, its time period remains the same,
but its wavelength decreases rapidly,
thus causing the water to pile up to form
tremendous crests, in an effect known as
"shoaling".

14. Most tsunamis are caused by earthquakes
generated in a seduction 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 seduction and instead the two plates
become "stuck".
Subduction Zones are Potential Tsunami Locations

15. As the stuck plate continues to descend into the
mantle
the motion causes a slow distortion of the
overriding plage.
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.
Accumulated Seismic Energy

18. Tsunamis occur most frequently in the Pacific
Ocean, but are
a global phenomenon; they are possible
wherever large bodies of
water are found, including inland lakes, where
they can be caused
by landslides.
Japan is a nation with the most recorded
tsunamis in the
world. The earliest recorded disaster being that
of the 684 A.D.

19. View of a Tsunami Taken By A Satellite

21. Generation Of Tsunamis
A Tsunami is generated when a large
amount of water is displaced which is done-:
 Mainly By The Earthquakes.
 By The Landslides.
 By Volcanic Eruptions.
 By Impact Events like Meteorite impacts

22. Earthquakes – The Major Cause
 The Sea floor abruptly
deforms and displaces the
sea water lying above.
 Large vertical movements
of earth's crust can occur at
plate boundaries which are
called “faults”.

23.  Tsunamis may reach a maximum vertical
height onshore above sea level, often called
a run up height, of 10, 20, and even 30
meters.
 For a typical ocean Depth of 4000m, a
tsunami moves with a speed about
700km/hr.
 The fast-moving water associated with the
inundating tsunami can crush homes and
other coastal structures.

24. TheTsunami Affected Countries

25. The Tsunami Affected Countries

26. Signs Of An Approaching Tsunami
 Often no advance
warning of an
approaching Tsunami
 An earthquake felt near a
body of water may be
considered an indication
that a tsunami will shortly
follow.

27. Warnings And Prevention
 Early warnings come from
the nearby animals as
they sense danger and flee
to higher grounds.
 Tsunami walls for the
reduction in the damage.
 Tsunami warning system
alert the people before the
wave reaches the shore

28.  Tsunami death toll
tops 118,000.
 Around 10,000 killed in
India.
 In Thailand, more than
4,000 are feared dead
and dozens of deaths are
reported in Malaysia,
Myanmar and Maldives.
 WHO estimates five
million people are without
basic needs.

29. Calong, A land of 13,000 “ vaporized”
by Tsunami

30. On
December 26, 2004
The Tsunami
That Struck
Thailand

31. The Islamic Relief
 Responded to the emergency
in hours.
 Building enough homes to
accommodate five families a
week.
 Highly successful because of
the close and constant
involvement of the affected
communities.
 Still working for the
betterment of the victims.

32. RELIEF WORKS IN INDIA
 Donations done under
the Prime Minister Relief
Fund.
 Rice, mats, medicines
were provided.
 ITC distributed over 1
lakh shirts to the victims.
 New houses were
provided.

33.  Loss of life and property can be reduced by
proper planning.
 Tsunami warnings can be made to aware
peoples.
 Stay away from all low lying coastal areas.
 Never go down to the shore to watch
tsunami.
 Stay out of low lying danger areas until an
“all-clear” is issued by competent authority.