Synopsis: Terrible Tsunami

Tsunamis are caused by violent disturbances of the sea floor; usually due to an earthquake. The 2004 “Christmas tsunami” offshore of Sumatra was one of the worst natural disasters on record. Fewer people died in Japan in 2011, but the giant waves caused explosions, havoc and public radiation exposures at a six-reactor nuclear complex. What are tsunamis? Are they predictable? What are people doing to reduce the harm?

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Discussion Questions

1. Discuss the location and importance and structure of the Ring of Fire. Why is it associated with earthquakes, volcanoes and tsunamis?
2. Map the location of series of earthquakes in a) the faults east of Japan and b) southwest of Sumatra, Indonesia. Then discuss the theory that large quakes increase pressure on adjacent sections of the fault, which can quickly trigger a nearby earthquake.
3. Discuss the different kinds of waves that move energy: water, sound, and the many forms of electromagnetic radiation, including ultraviolet light, visible light and radio waves). Define amplitude, frequency, and velocity in relation to waves. What kind of waves can pass through a vacuum?
4. Explore the relationship between wavelength, ocean depth (which limits wave amplitude) and travel speed, with the goal of explaining the rapid travel and short amplitude of tsunamis across the open ocean.

Lesson Plans/Activities

1. Find a list of historic tsunamis and mark them on a map. Then do the same for large earthquakes. Do you see any pattern? (The Ring of Fire should emerge from these marks.) Follow this learning activity for a more in-depth exploration of the Ring of Fire (recommended for grades 9-12).
2. Class exercise: If you live in a tsunami zone, discuss safety measures.
3. Ready, set, tsunami! This NOVA activity teaches students to calculate tsunami speed and travel times.
4. More tsunami activities and resources appear on SEACOOS’s website.