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SREE NARAYANATRAINING COLLEGE

SREEKANDESWARAMPOOCHAKKAL

2014-2015

SUBMITTED BY JISHA ANTONY

SOCIAL SCIENCEREG NO : 16914383005

POWER POINT PRESENTATION ON

TSUNAMI

INTRODUCTION A Tsunami also known as a seismic sea wave , is a

series of water waves caused by the displacement of a large volume a body of water, generally an ocean or a large lake . Earthquakes, volcanic eruptions and other water explosions , landslides , glacier calving, meteorite impacts and other disturbances above or below water all have the potential to generate a tsunami. Tsunamis generally consist of a series waves with periods ranging from minutes to hours, arriving in a so called wave train

CONTENT

ETYMOLOGY Tsunamis are sometimes referred to as tidal

waves, which are unusually high sea waves that are triggered especially by earthquakes. In recent years, this term has fallen out of favor , especially in the scientific community, because tsunami actually has nothing to do with tides. Tsunami and tides both produce waves of that move inland, but in the case of tsunami the inland movement of water may be much greater, giving impression of an incredibly by high tide.

HISTROYWhile Japan may have the longest recorded history of

tsunami, the sheer destruction caused by 2004 Indian ocean earthquake and tsunami event mark it as the most devastating of it kind in modern times, killing around 230,000 people

Tsunamis are an often underestimated hazard in the Mediterranean sea region and Europe in generally. Of historical and current impotents

Eg: the 1755 Lisbon earthquake and tsunami, the 1783 Calabria earthquake, 1908 Messina earthquake and tsunami

The “ Storegga ” slide in the Norwegian sea and some examples of tsunami affecting British isles refer to landslide and meteor tsunamis predominately and less to earthquake induced waves . Such as wave travels at well over 800 kilometer per hour, but owing to the enormous wavelength at the wave oscillation at any given point takes 20 or 30 minutes to complete cycle and has an amplitude of only 1 meter

The Reson for the japaneses name “ Harbour wave” is that sometime a villages fishermen would sail out, and enconter no unusual waves without at sea fishing, and come back to land to find their village devastate a huge way. About 80% of tsunami occur in the pacific ocean they are possible wherever there are large bodies water, including land they are caused by earthquake landslid volcanic…

DRAWBACKS AII waves have a positive and negative peak ,

i.e. a ridge and a trough. In the case of a propagating wave like a tsunami , either may be the first to arrive .Drawback and exceed hunders of meters , and people unwire of the danger sometimes remain near shore to satisfy their curiosity or to collect fish from the exposed seabed.

This means that if the drawback phase is the part of waves to arrive , this sea will recede , with areas well below sea level exposed after 3 minutes . This may sweep victims and debris some distance from the land. The process repeats as the next wave arrives.

WARNINGS AND PREDICTIONS

A tsunami cannot be precisely predicted , even If the magnitude and location of an earthquake is known. Geologists, oceanographers, and seismologists analyze each earthquake and based many factors may or may not issue tsunami warning . One of successful systeam uses bottom pressure sensors, attached to buoys , which constantly monitor the pressure of the overlying water colum `

CONCULSIONThe Greek historian Thucydides suggested in his late – 5th

century BC History of the Peloponnesian War, that tsunamis were related to submarine earthquakes , but the understanding of a tsunamis nature remained slim until the 20th century and much remains unknown. Major areas of current research include trying time to determine some large earthquakes do not generate tsunami while other smaller ones do; trying to accurately forecast the passage of tsunamis across the oceans; and also to forecast how wave would interact with specific shorelines.

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