TSUNAMI
CONTENTS
1. Tsunami
2. History of Tsunami
3. Causes of Tsunami
4. Characters of Tsunami
5. Where does it occur?
6. Effects of Tsunami
7. Warning and Monitoring of Tsunami
8. Prevention
9. Brief summary of Tsunami 2004
TSUNAMI
Tsunami is a Japanese word Tsu means ‘harbour’ and nami means ‘wave’. They are called tidal waves but they
have actually nothing to do with the tides. However their appearance from shore is similar to rapidly rising or
falling tides.Tsunami is a series of wave created when water is moved very quickly. Tsunami is gravity wave
system, triggered by vertical disturbances in ocean. They are long waves sometime with hundreds of miles b/w their
crests, just like the concentric waves generated by an object dropped into a pool.
HISTORY
 First tsunami was recorded in 1480 B.C. in eastern Mediterranean, when the Minoan civilization was wiped out.
 A large tsunami accompanied by the earthquake of Lisbon in 1755.
 The Kutch earthquake of June 16, 1819 generated strong tsunami which submerged the coastal areas and damage
to ships and country made boats of fishermen.
 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.
 Hawaiian tsunami on 1 April 1946 destroyed the city of Hilo, killing 159 people. Other recent tsunami that have
hit Hawaii are those of 1952,1957,1960,1964 and 1975 .
 Total 65 destructive tsunamis struck Japan between 684 A.D to 1960.
 On 16 August 1976, a large earthquake in the Moro Gulf in the Philippines generated a destructive local tsunami
which killed over 8,000 persons.
 Christmas tsunami 2004 in Indian ocean.
 And last one Japan Tsunami in 2011.
CAUSES OF TSUNAMI
1. Earthquake
2. Icefall
3. Volcanic eruptions
4. Heavy rainfall
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5. Cosmic impacts
6. Landslide
1. Earthquake – The Major Cause 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”.
2. Volcanic Eruptions-Volcanic eruptions create disturbance undersea by creating great force and thus generate
tsunami.
3. Icefall - If their height is larger than their width, they can be unstable following break off and roll over,
potentially creating a giant wave. Iceberg capsizing poses the least- recognized practical hazard to humans of the
tsunami-causing mechanisms related to calving of ice masses
4. Heavy Rainfall - Heavy rainfall cause overflow of water and generate tsunamis
5 Cosmic Impacts - When a meteorite or an alien force impact the ocean area disturbing the water from above ,
tsunami is caused.
6. Landslides - When there is large landslide in mountains in the sea, the tsunami is caused and effect fell at bays.
WHY TSUNAMI IS DESTRUCTIVE
1. There is no effect of Tsunami in the sea, even if we are only half to one kilometer from coast.
2. Tsunami may come in waves with a time gap of 40 min to 1hr b/w successive major waves. In one major wave,
there may be up to ten sub waves.
3. Although the speed of the approaching Tsunami waves at coast gets reduced from 700-800 km to 50-60 km/hr,
they carry enormous energy.
4. The height of waves at coast can go up to 50 to 70 feet. At point of origin, although there is a large scale
displacement of water, the increase in wave length is a few inches only.
5. The retreating Tsunami waves are as quick and as dangerous as their approach and cause as much damage.
6. Major devastation is restricted up to 500 m inland.
7. Tsunami causes more havoc along beaches which have ocean thousands of meter deep near the coas.
In comparison, if the shallow water extends to more than 100 km the effect will be that much less.
The fast-moving water associated with the inundating tsunami can crush homes and other coastal structures.
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WHERE • Tsunamis occur most frequently in the Pacific Ocean, but area 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.
EFFECTS OF TSUNAMI DESTRUCTION
 The amount of energy and water contained in a huge tsunami can cause extreme destruction when it strikes
land.
 The initial wave of a huge tsunami is extremely tall; however, most damage is not sustained by this wave. Most
of the damage is caused by the huge mass of water behind the initial wave front, as the height of the sea keeps
rising fast and floods powerfully into the coastal area. It is the power behind the waves, the endless rushing
water that causes devastation and loss of life.
 When the giant breaking waves of a tsunami batter the shoreline, they can destroy everything in their path.
 Destruction is caused by two mechanisms: the smashing force of a wall of water traveling at high speed, and
the destructive power of a large volume of water draining off the land and carrying all with it, even if the wave
did not look large.
 Objects and buildings are destroyed by the sheer weight of the water, often reduced to skeletal foundations and
exposed bedrock. Large objects such as ships and boulders can be carried several miles inland before the
tsunami subsides.
 Tsunami waves destroy boats, buildings, bridges, cars, trees, telephone lines, power lines - and just about
anything else in their way.
 Especially along a high seismic area, known as the Ring of Fire, tsunamis may have dramatic consequences as
they hit less developed countries.
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 The buildings infrastructure in these poorer nations are not well built and cannot withstand the impact of the
tsunami. Whole areas and towns are a picture of destruction as the tsunami leaves at trail devastation and
misery behind it.
DEATH
 One of the biggest and worst effects of a tsunami is the cost to human life because unfortunately escaping a
tsunami is nearly impossible.
 People living in coastal regions, towns and villages have no time to escape. The violent force of the tsunami
from gas, damaged tanks and floating debris are another cause of death. The tsunami of December 2004 that
struck South East Asia and East Africa killed over 31,000 people in Sri Lanka only, leaving 23,000 injured.
DISEASE
 Tsunami waves and the receding water are very destructive to structures in the run-up zone. The areas close to
the coast are flooded with sea water, damaging the infrastructure such as sewage and fresh water supplies for
drinking.
 Flooding and contamination of drinking water can cause disease to spread in the tsunami hit areas. Illnesses
such as malaria arise when water is stagnant and contaminated.
 Under these conditions it is difficult for people to stay healthy and for diseases to be treated, so infections and
illnesses can spread very quickly, causing more death.
ENVIRONMENTAL IMPACTS
 Tsunamis not only destroy human life, but have a devastating effect on insects, animals, plants, and natural
resources. A tsunami changes the landscape.
 It uproots trees and plants and destroys animal habitats such as nesting sites for birds. Land animals are killed
by drowning and sea animals are killed by pollution if dangerous chemicals are washed away into the sea, thus
poisoning the marine life.
 The impact of a tsunami on the environment relates not only to the landscape and animal life, but also to the
man-made aspects of the environment. Solid waste and disaster debris are the most critical environmental
problem faced by a tsunami-hit country.
PSYCHOLOGICAL EFFECTS
 Victims of tsunami events often suffer psychological problems which can last for days, years or an entire
lifetime. Survivors of the Sri Lankan tsunami of December 2004 were found to have PTSD (post traumatic
stress disorder) when examined by the World Health Organization (WHO): 14% to 39% of these were children,
40% of adolescents and 20% of mothers of these adolescents were found to have PTSD 4 months after the
tsunami.
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 These people were suffering from grief and depression as their homes, businesses and loved ones were taken
from them. Many still had PTSD. Periliya Village counts 2,000 dead and 400 families became homeless. These
people were found to still have psychological problems 2 years after the tsunami.
SIGNS OF AN APPROACHING TSUNAMI
 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.
WARNINGS OF TSUNAMI
 Early warnings come from the nearby animals as they sense danger and flee to higher grounds.
 Tsunami walls for the reduction in the damage.
 When an earthquake of more than 7.5 on Richter scale is detected by sensors, placed on the surface of the sea
floor . Tsunami watch is issued.
 If Tidal Stations confirm a follow up wave, Tsunami Warning follows. Precise time at different points on the
coast can be predicted but the height of waves, its size and duration cannot be gauzed.
 The Warning is lifted after an area is clear of dangerous waves for two or more hours.
PREVENTION
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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
TSUNAMI 2004
 The 2004 Indian Ocean earthquake occurred at 00:58:53 UTC on 26 December with the epicenter off the west
coast of Sumatra, Indonesia. The shock had a moment magnitude of 9.1–9.3 and a maximum Mercalli intensity
of IX.
 Depth: 30,000 m
 Date: 26 December 2004
 Total damage: 19.6 billion USD (2017 USD)
 Location: Band
 Did you know: The 2004 Indian Ocean earthquake and tsunami is the sixth-deadliest natural disaster in history
by estimated death toll (280,000).
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Important Tsunami Facts
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Tsunami is a Japanese word which means 'harbour wave'
Earthquakes under the sea are the main causes of Tsunamis
The biggest tsunami ever was at Lituya Bay, Alaska on July 9, 1958
Earliest tsunamis was in Sicily 8,000 years ago
Landslides and volcanoes can also cause tsunami
Major Tsunamis
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Japan - March 11, 2011
Indian Ocean - 26 December 2004.
Papua New Guinea - 17 July 1998
Sea of Japan - 26 May 1983
Alaska Britis Columbia - 27 March 1964
Chili - 22 May 1960
Aleutian Islands - 1 April 1946
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