Transcript A tsunami - solarsystemmesco

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 :
1. Definition of Tsunami
2. What causes of Tsunami?
3. 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.
1. Tsunami can be generated when
the see floor abruptly deforms and
vertically displaces the overlying
water.
2. 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.
3. 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".
Subduction Zones are Potential
Tsunami Locations
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
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
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
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 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.