this will help u to get knowledge about tsunami's

1. TSUNAMI

3. Important points:
 In deep ocean, tsunami has
small amplitude and travels
with speed of jet airliner.
When approaching land, speed
slows and amplitude
increases dramatically.

4. HOWTSUNAMIISCAUSED
Tsunami are often generated by large and shallow
earthquakes at subduction zones whereoceanic plates
descend into the deepermantle. These types of
earthquakes can produce the rapid displacements of the
ocean floor that generate tsunamis.

5. Properties of
ocean waves & tsunami
Periods Lengths
Wind-blown short: 5 seconds 39 meters (130 ft)
Ocean waves medium: 10 seconds 156 meters (510 ft)
long: 20 seconds 624 meters (2050 ft)
Tsunami super long: 3600 seconds >800 kilometers
(60 minutes) (520 miles)
LONG period:
Wind waves wash on shore for < 5 seconds. Tsunami can wash on
shore for 10 - 15 minutes!

6. DAMAGE CAUSED BY TSUNAMI
Tsunamis causedamage by two mechanisms:the
smashing
forceof a wall of water travellingat high speed,
and the destructivepower of a large
volume of water drainingoff the land andcarrying
a largeamount of debris with it,
even with waves that do not appear to be large.

7. Deep-oceanAssessmentand Reportingof Tsunami(DART)
PacificTsunamiWarning System

8. RECENT TSUNAMI
Date Cause Height Location Deaths
1883 Volcanic eruption 35 m Indonesia 36,000
1896 Earthquake 29 m Japan 27,000
1933 Earthquake 30 m Japan 3,000
1946 Earthquake 15 m Alaska 175
1960 Earthquake 10 m Chile >1,250
1964 Earthquake 6 m Alaska 125
1992 Earthquake 26 m Nicaragua 170
1992 Earthquake 26 m Indonesia >1,000
1993 Earthquake 31 m Japan 239
1994 Earthquake 14 m Indonesia 238
1998 Landslide 15 m Papua >2,200
2004 Earthquake 30 m Sumatra 245,000

9.  TheDecember 26,2004Indian Ocean tsunami was caused by an earthquakethat is thought to havehadthe energyof
23,000Hiroshima-type atomic bombs.
 Theepicenter of the9.0 magnitudequakewas underthe Indian Ocean nearthe west coast of the Indonesianisland of
Sumatra.
Theviolent movementof sections of the Earth’s crusts knownas tectonic plates
displaced an enormous amountof water, sending powerful shock waves inevery direction.

10.  Thetectonic plates in this area had been pushing against each other, building pressure for
thousands of years – they continue to do so and will likely causeunderwaterearthquakes
and tsunamis inthe future.
 Atsunami is a series of waves, and the first wave maynot bethe most dangerous. A tsunami
“wave train” maycome as surges five minutes to an hour apart. Thecyclemay be markedby the
repeated retreat and advance of the ocean.
 Theearthquake-inducedtsunami resulted inat least 155,000fatalities, 500,000injuries, and
damages that exceeded $10billion. Also, it is estimated that 5million people lost their homes or
access to food and water.

11. DONE
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