Tsunami is a Japanese word meaning ‘harbor

wave’. It is constituted with two syllables, Japanese

language meaning harbour ("tsu", 津) and wave

("nami", 波).

Tsunami is a wave train or series of waves

generated, by impulsive disturbance that vertically

displaces the water column, in water body.

Earthquake, landslides, volcanic eruption, explosion

and even the impact of cosmic bodies like

meteorites commonly generate tsunami. Tsunami

savagely attacks coastlines causing devastating

property damage and loss of lives.

• 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.

• 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.

Many people have the mistaken belief that tsunamis are

single waves. They are not. Instead tsunamis are "wave

trains" consisting of multiple waves. The chart below is a

tidal gauge record from Onagawa, Japan beginning at the

time of the 1960 Chile earthquake. Time is plotted along the

horizontal axis and water level is plotted on the vertical axis.

Note the normal rise and fall of the ocean surface, caused by

tides, during the early part of this record. Then recorded are

a few waves a little larger than normal followed by several

much larger waves. In many tsunami events the shoreline is

pounded by repeated large waves.

Volcanic eruptions

Icefalls

Heavy rainfall

Seismic activities

Submarine landslides

Cosmic impacts

Volcanic eruptions and icefalls create disturbance in water and generate tsunami.

Heavy rainfall cause overflow of water and generate tsunamis.

.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

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".

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".

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.

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.

.Tsunami is one of the earth’s disaster. It was a Japanese

word

meaning “harbor wave,” used as the scientific term for a

class

of abnormal sea wave that can cause catastrophic

damage when it hits a coastline.

.Tsunamis can be generated by an undersea earthquake,

an undersea landslide, the eruption of an undersea volcano,

or by the force of an asteroid crashing into the ocean.

The earthquake that caused the Sumatran tsunami

is the second largest to ever be recorded on a

seismograph.

The magnitude of the earthquake was 9.3 on the

Richter scale.

This earthquake had the longest duration, that is

lasted for the longest amount of time, ever

observed, lasting approximately 10 minutes.

It caused the entire planet to vibrate by as much

as 1 cm (0.5 inches), and triggered other

earthquakes as far away as Alaska.

There were no Tsunami Warning Systems in

the Indian Ocean on the 26th December

2004. Had there had been, many lives

could have been saved.

A 10 year old tourist named Tilly Smith, who

had studied tsunamis at school, noticed the

receding tide and frothing bubbles, and

told her parents there was going to be a

tsunami. Her parents told the rest of the

beach and everyone was evacuated

safely.

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

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”.

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.

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.

Tsunami death tolltops 118,000.

Around 10,000 killed inIndia.

In Thailand, more than4,000 are feareddead and dozens ofdeaths are reported inMalaysia, Myanmarand Maldives.

WHO estimates fivemillion people arewithout basic needs.

Calong, A land of 13,000 “

vaporized” by Tsunami

The Tsunami

That Struck

Thailand

On

December 26, 2004

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.

Responded to theemergency in hours.

Building enough homes toaccommodate fivefamilies a week.

Highly successful becauseof the close and constantinvolvement of theaffected communities.

Still working for thebetterment of the victims.

Early warnings comefrom the nearbyanimals as they sensedanger and flee tohigher grounds.

Tsunami walls for thereduction in thedamage.

Tsunami warning systemalert the people beforethe wave reaches theshore

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.