1 / 41

Tsunamis

Tsunamis. Tsunami. A Tsunami is a wave train, or series of waves that is generated in a body of water by an impulsive disturbance that vertically displaces the water. Pronounced “Sue-Nah-Me”. Tsunami Triggers. Earthquakes Landslides Volcanic eruptions Explosions

hayley
Download Presentation

Tsunamis

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Tsunamis

  2. Tsunami • A Tsunami is a wave train, or series of waves that is generated in a body of water by an impulsive disturbance that vertically displaces the water. • Pronounced “Sue-Nah-Me”

  3. Tsunami Triggers • Earthquakes • Landslides • Volcanic eruptions • Explosions • Even the impact of cosmic bodies (meteorites)

  4. What does “Tsunami” mean? • “Harbor Wave” • The terms “Tidal Wave” and “Seismic Sea Waves” are incorrect • Tsunamis are not determined by the tide, and they are not always created by seismic activity.

  5. Tsunami Waves • Different than regular wind-generated waves • Tsunami waves have long periods and large wavelengths. • Normal waves have short periods and small wavelengths

  6. The Difference • Wind waves roll in rhythmically, one wave after another, might have a period of about 10 seconds and a wavelength of 150m. • Tsunami waves can have an excess of 100km and a period on the order of one hour.

  7. Bellringer • What is a difference between regular ocean waves and a tsunami wave?

  8. Objectives • Be able to explain the various causes of tsunamis

  9. Tsunami Waves • Behave as shallow-water waves. • In deep ocean waters (~4000m) tsunami waves travel at about 200m/s (450mph) • They lose energy very slowly so they can travel huge distances. • Often crossing oceans with limited energy losses.

  10. Earthquake Tsunamis • Generated when the sea floor abruptly deforms and vertically displaces the overlying water. • Waves are formed as a the displaced water mass attempts to regain its original position. • The larger the area of sea floor elevated, and the larger the elevation the greater the tsunami.

  11. Earthquake Tsunami

  12. Earthquake Tsunami

  13. Other Causes of Tsunamis • Generated by any disturbance that displaces a large water mass from its equilibrium position. • Submarine Landslide

  14. Lituya Bay, Alaska: July 9, 1958

  15. Lituya Bay, Alaska: July 9, 1958 • https://www.youtube.com/watch?v=SCn480_TUgY • Initial splash was 525m high

  16. Other Causes of Tsunamis • Submarine Volcano

  17. Submarine Volcano

  18. Other Causes of Tsunamis • Cosmic Impact

  19. Cosmic Impact

  20. Cosmic Impact

  21. Tunguska Event, Russia • 60m to 190m rock that hit the Tunguska river in Russia in 1908. • Largest impact in recorded history. • Many scientist believe the rock actually exploded above the ground. • Surviving witnesses said it felt like the wind was on fire and sounded like constant connon fire.

  22. Tunguska Event, Russia

  23. Tunguska Event, Russia • The epicenter in 2008 (100 years later)

  24. Cosmic Impact

  25. The Moon

  26. Cosmic Impact

  27. Checkpoint • What is common about how all types of tsunamis are formed?

  28. Bellringer • What is common about how all types of tsunamis are formed?

  29. Objective • Understand why tsunamis cause so much destruction

  30. Tsunami Approaching Land • Shore water will recede before tsunami arrives • As the water the tsunami is traveling in gets shallower the wave grows in height. • A tsunami may be imperceptible at sea, but grow to several meters in height near the coast. • At the coast it may appear as a rapidly rising or falling tide, a series of breaking waves, or even a bore.

  31. What’s a bore?

  32. Tsunami Approaching Land

  33. Tsunami Approaching Land

  34. Tsunami on Land • Begin to lose energy as they rush onshore from bottom friction and turbulence • Some energy is reflected back offshore • Reach the shore with tremendous amounts of energy so they take a very long time to stop charging forward.

  35. Tsunami on Land • Great erosional potential, stripping beaches of sand, trees, and vegetation that may have taken years to accumulate . • How far the flooding reaches inland depends on the defenses installed and the natural terrain.

  36. Tsunami on Land • If the land is very flat flooding can go for kilometers • If the land is steep it may only go 100 meters • Typically go above high-water level

  37. Tsunami Destruction • Fast-moving water can crush homes, throw cars and boats, and sweep people kilometers away. • Knockout power lines, break gas lines • Can sweep debris back into the ocean when it recedes

  38. Tsunami Destruction • https://www.youtube.com/watch?v=av1Ieq0q06Q

  39. Checkpoint • Why does the wave height of a tsunami increase as it gets closer and closer to shore? • What are the main factors in determining how far inland a tsunami wave goes?

  40. Japan Tsunami Questions

More Related