Tsunami Attacks

Tsunami Attacks

Presented By :M.A MALIK

A tsunami (pronounced soo-NAA-mee) is a series of waves (called a "wave train") generated in a body of water by a pulsating or abrupt disturbance that vertically displaces the water column.

Tsunami Description :Tsunami Description :

1.1. Definition of TsunamiDefinition of Tsunami2.2. What causes of Tsunami?What causes of Tsunami?3.3. Where do tsunamis occurs in the Where do tsunamis occurs in the

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Tsunami is a Japanese word meaning Tsunami is a Japanese word meaning ‘harbor wave’. It is constituted with two ‘harbor wave’. It is constituted with two syllables, Japanese language meaning syllables, Japanese language meaning harbour ("tsu", harbour ("tsu", 津津 ) and ) and wave ("nami", ("nami", 波波 ).).

Tsunami is a wave train or series of waves Tsunami is a wave train or series of waves generated, by impulsive disturbance that generated, by impulsive disturbance that vertically displaces the water column, in vertically displaces the water column, in water body. Earthquake, landslides, water body. Earthquake, landslides, volcanic eruption, explosion and even the volcanic eruption, explosion and even the impact of cosmic bodies like meteorites impact of cosmic bodies like meteorites commonly generate tsunami. Tsunami commonly generate tsunami. Tsunami savagely attacks coastlines causing savagely attacks coastlines causing devastating property damage and loss of devastating property damage and loss of lives.lives.

1.1. Tsunami can be Tsunami can be generated when the see floor abruptly when the see floor abruptly deforms and vertically deforms and vertically displaces the overlying displaces the overlying water. water.

2.2. Tectonic earthquakes are a Tectonic earthquakes are a particular kind of particular kind of earthquake that are earthquake that are associated with the earth’s associated with the earth’s crustal deformation, when crustal deformation, when these earthquakes occur these earthquakes occur beneath the see, the water beneath the see, the water above the deformed area is above the deformed area is displayed from its displayed from its equilibrium position. equilibrium position.

3.3. Waves are formed as the Waves are formed as the displaced water mass, which displaced water mass, which acts under the influence of acts under the influence of gravity, attempts to regain gravity, attempts to regain its equilibrium its equilibrium

• Ocean waves are normally Ocean waves are normally divided into 3 groups, divided into 3 groups, characterized by depth:characterized by depth:•• Deep water Deep water •• Intermediate water Intermediate water •• Shallow water Shallow water

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

Most tsunamis are caused by Most tsunamis are caused by earthquakes generated in a earthquakes generated in a subduction zone, an area where an subduction zone, an area where an oceanic plate is being forced down oceanic plate is being forced down into the mantle by plate tectonic into the mantle by plate tectonic forces. The friction between the forces. The friction between the subducting plate and the overriding subducting plate and the overriding plate is enormous. This friction plate is enormous. This friction prevents a slow and steady prevents a slow and steady

rate of subduction and instead the rate of subduction and instead the two plates become "stuck". two plates become "stuck".

Subduction Zones are Potential Tsunami Locations

As the stuck plate continues to As the stuck plate continues to descend into the mantle the descend into the mantle the motion causes a slow distortion motion causes a slow distortion of the overriding plage. The of the overriding plage. The result is an accumulation of result is an accumulation of energy very similar to the energy energy very similar to the energy stored in a compressed spring. stored in a compressed spring. Energy can accumulate in the Energy can accumulate in the overriding plate over a long overriding plate over a long period of time - decades or even period of time - decades or even centuries.centuries.

Accumulated Seismic Energy

Energy accumulates in the overriding Energy accumulates in the overriding plate until it exceeds the frictional plate until it exceeds the frictional forces between the two stuck plates. forces between the two stuck plates. When this happens, the overriding When this happens, the overriding plate snaps back into an unrestrained plate snaps back into an unrestrained position. This sudden motion is the position. This sudden motion is the cause of the tsunami - because it gives cause of the tsunami - because it gives an enormous shove to the overlying an enormous shove to the overlying water. At the same time, inland areas water. At the same time, inland areas of the overriding plate are suddenly of the overriding plate are suddenly lowered. lowered.

Earthquake Causes Tsunami

Earthquake Causes Tsunami

CharacteristicsCharacteristicsMove at high speedsCan travel enormous distances with little energy loss

Can cause damage thousands of miles from its origin

May be several hoursseveral hours between its creation and its impact on the coast

Effects of Effects of TsunamisTsunamis

•Destruction of human life (100,000+)•Destruction of property•Spread of disease•Destruction of ecosystems

CHANGES AFTER OCCURENCE OF TSUNAMI

CHANGES AFTER OCCURENCE OF TSUNAMI

A small boat gets stuck in a tsunami whirlpool.

Residents look at a massive crack in the ground.

Cars and other debris swept away by tsunami tidal waves

Waves of tsunami topple trees.

Tsunami is one of the earth’s disaster. It Tsunami is one of the earth’s disaster. It was a Japanese word meaning “harbor was a Japanese word meaning “harbor wave,” used as the scientific term for a wave,” used as the scientific term for a class of abnormal sea wave that can class of abnormal sea wave that can cause catastrophic damage when it hits cause catastrophic damage when it hits a coastline. a coastline. Tsunamis can be generated Tsunamis can be generated by an undersea earthquake, an undersea by an undersea earthquake, an undersea landslide, the eruption of an undersea landslide, the eruption of an undersea volcano, or by the force of an asteroid volcano, or by the force of an asteroid crashing into the ocean. crashing into the ocean.