Tsunamis By Philip Stubbs
What is a Tsunami? <ul><li>Japanese Meaning: Tsu = Harbor  Nami = Wave </li></ul><ul><li>Tsunamis= sequences of waves (wav...
Characteristics of Tsunami Waves in Deep Water <ul><li>Have characteristics of shallow-water waves in deep water. The rati...
Tsunami coming towards Land <ul><li>A transformation occurs when a tsunami goes into shallow water. </li></ul><ul><li>Sinc...
Tsunami approaching Land
Tsunami on Land <ul><li>As soon as tsunamis enter land, they lose energy. The rate that they lose energy is inversely rela...
Tsunamis <ul><li>No advance warning of approaching tsunami </li></ul><ul><li>Good indicator: earthquake near body of water...
The top picture shows Sri Lanka in 2004 when the tsunami hit SE Asia. (flooding and violent waves) The bottom picture show...
Bibliography <ul><li>&quot;ABC News: Fast Facts on Tsunamis.&quot;  ABC News: Online news, breaking news, feature stories ...
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Tsunamis

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Tsunamis

  1. 1. Tsunamis By Philip Stubbs
  2. 2. What is a Tsunami? <ul><li>Japanese Meaning: Tsu = Harbor Nami = Wave </li></ul><ul><li>Tsunamis= sequences of waves (wave train) that form in body of water. </li></ul><ul><li>Water is displaced by things like earthquakes, landslides, and volcanoes. </li></ul><ul><li>Attack coastlines making them real dangerous when they hit land=altering landscapes and killing thousands of people. </li></ul><ul><li>Referred to tidal waves at time, but are not caused by winds. </li></ul><ul><li>Seismic Waves </li></ul>
  3. 3. Characteristics of Tsunami Waves in Deep Water <ul><li>Have characteristics of shallow-water waves in deep water. The ratio between water depth and wavelength is really small. </li></ul><ul><li>Long periods and long wavelengths. </li></ul><ul><li>Regular waves= wavelengths of 150m and periods of 10s </li></ul><ul><li>Tsunami waves=wavelengths over 100 km and periods longer than one hour. </li></ul><ul><li>Because of their small heights and long wavelengths, they can go unnoticed deep at sea. </li></ul><ul><li>Combo of transverse and longitudinal motion=circular motion </li></ul><ul><li>Speed= square root of the product of acceleration of gravity (9.8 m/s/s) and water depth. </li></ul><ul><li>If the water depth is 4000 m, the tsunami travels at a speed of about 200 m/s. </li></ul><ul><li>In the deepest oceans, the waves can exceed 600 miles per hour. </li></ul><ul><li>Tsunamis can cross over the Pacific in less than 24 hours. </li></ul>
  4. 4. Tsunami coming towards Land <ul><li>A transformation occurs when a tsunami goes into shallow water. </li></ul><ul><li>Since water depth is a factor in speed, a tsunami decreases in speed. </li></ul><ul><li>Since the speed decreases, the tsunami’s height will be taller (conservation of energy). </li></ul><ul><li>Top of waves travel quicker than bottom half </li></ul><ul><li>Very little energy lost because the wavelength does not decrease much. </li></ul><ul><li>When a tsunami hits land, it appears as a sequence of breaking waves. </li></ul>
  5. 5. Tsunami approaching Land
  6. 6. Tsunami on Land <ul><li>As soon as tsunamis enter land, they lose energy. The rate that they lose energy is inversely related to the wavelength. Wavelength decreases=loss of energy </li></ul><ul><li>Some of the energy is lost due to friction and turbulence. </li></ul><ul><li>As well as wavelength, period decreases also </li></ul><ul><li>Since wavelength decreases, frequency increases </li></ul><ul><li>Can reach heights up to 30 meters and even higher. </li></ul><ul><li>Run-up height= max vertical height onshore </li></ul><ul><li>The waves eventually break and flood land. </li></ul><ul><li>Areas within 200 meters of coast most at risk </li></ul>
  7. 7. Tsunamis <ul><li>No advance warning of approaching tsunami </li></ul><ul><li>Good indicator: earthquake near body of water </li></ul><ul><li>Good indicator: dramatic water level drop </li></ul><ul><li>80% of all tsunamis take place in Pacific Ocean </li></ul><ul><li>Hard to Predict and Prevent </li></ul><ul><li>Mainly take place in Asia-Pacific region </li></ul><ul><li>Very Common in Japan </li></ul>
  8. 8. The top picture shows Sri Lanka in 2004 when the tsunami hit SE Asia. (flooding and violent waves) The bottom picture shows Sri Lanka in 2004 a year before the tsunami hit SE Asia. (calm, harmless waves)
  9. 9. Bibliography <ul><li>&quot;ABC News: Fast Facts on Tsunamis.&quot; ABC News: Online news, breaking news, feature stories and more . 28 Dec. 2004. 06 Jan. 2009 <http://abcnews.go.com/Technology/Weather/story?id=365979>. </li></ul><ul><li>Newman, David. &quot;The Physics of Tsunamis.&quot; David Newman's Page . 2005. 06 Jan. 2009 <http://ffden2.phys.uaf.edu/212_spring2005.web.dir/Justin_Priest/Tsunami%20Physics.htm>. </li></ul><ul><li>&quot;Physics of Tsunamis.&quot; Earth and Space Sciences (Geology and Geophysics) at UW . 23 Mar. 2005. 06 Jan. 2009 <http://www.geophys.washington.edu/tsunami/general/physics/physics.html>. </li></ul><ul><li>Uy, Anthony. &quot;The Physics of Tsunamis: The Harbor Wave.&quot; UBC PhysAstro: Home Page . 2006. 06 Jan. 2009 <http://www.physics.ubc.ca/~outreach/phys420/p420_05/anthony/The%20Physics%20of%20Tsunamis.htm>. </li></ul>

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