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Tsunami Attacks. Presented By : M.A MALIK. Mesco Grades School. 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. Introduction.
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Tsunami Attacks Presented By : M.A MALIK Mesco Grades School
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.
Introduction Tsunami Description : • Definition of Tsunami • What causes of Tsunami? • Where do tsunamis occurs in the world
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. WHAT?
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 WHAT CAUSE?
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". WHAT CAUSE?
Subduction Zones are Potential Tsunami Locations WHAT CAUSE? 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 subducting plate and the overriding plate is enormous. This friction prevents a slow and steady rate of subduction and instead the two plates become "stuck".
Accumulated Seismic Energy WHAT CAUSE? 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.
Earthquake Causes Tsunami Earthquake Causes Tsunami WHAT CAUSE? 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.
Characteristics • Move at high speeds • Can travel enormous distances with little energy loss • Can cause damage thousands of miles from its origin • May be several hours between its creation and its impact on the coast
Effects of Tsunamis • Destruction of human life (100,000+) • Destruction of property • Spread of disease • Destruction of ecosystems
CHANGES AFTER OCCURENCE OF TSUNAMI
Conclusion 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.