Tsunamis: Earthquakes Deadly Partners

Name: _________________________________       Date: _____________

The Indonesian earthquake that struck on December 26, 2004 was the most violent to hit the planet in forty years. It also spawned the most destructive tsunami in all of recorded history, killing about 230,000 people worldwide.

How exactly do earthquakes trigger tsunamis? What are the steps in tsunami formation? Once an earthquake has struck, can tsunamis be monitored so people living along the world's coasts can be warned in time? You'll explore all of these questions in this activity.

1. To start out, view a NOAA Animation of the global spread of the tsunami of December 26, 2004. Starting at the quake's epicenter, describe the sequence in which the tsunami struck each of Earth's continents.
   
   
   
   
2. Based on the animation, was there any continent not touched by the tsunami?
   
   
   
   
3. Visit the USGS page Life of a Tsunami. Read Initiation and look at the diagram. (Blue shows ocean and brown the sea floor.) Describe what happens to the seafloor and water column during a submarine (underwater) earthquake.
   
   
   
   
4. Explain how potential energy is changed into kinetic energy (energy of motion) during a submarine earthquake.
   
   
   
   
5. Scroll to Split. Describe the two parts a tsunami splits into within minutes of the earthquake.
   
   
   
   
6. Continue down the page to Amplification.
   1. How do the amplitude and wavelength of the local tsunami change as it moves along the continental slope?
      
      
      
      
   2. How does this effect the leading wave?
      
      
      
      
7. Read Runup. What does runup measure?
   
   
   
   
8. How is a tsunami wave different from normal surf waves at the beach?
   
   
   
   
9. What causes most of the damage from a tsunami?
   
   
   
   
10. 1. What are tsunami bores?
       
       
       
       
    2. What are edge waves?
       
       
       
       
11. Explain why it's unwise to return to a beach for several hours after the first tsunami runup.
    
    
    
    
12. One of the reasons the Indonesian tsunami was so catastrophic was the absence of effective monitoring or warning systems in southern Asia. But the technology for such a system exists. View this DART Animation, then read the description. Explain how the bottom pressure recorder (BPR), surface buoy, satellite, and warning centers on land all work together when a tsunami strikes.
    
    
    
    
13. What do the letters in "DART" stand for?