Question 7

Here are the two earthquakes' epicenters and approximate rupture zones. Now, thinking about all the information you've been given, which would you expect to generate the bigger tsunami? (Choose the best answer.)

Map of the subduction zone off the coast of Sumatra with the 2004 Indian Ocean Tsunami and the 2005 Nias Island Tsunami rupture zones marked.
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The correct answer is A. In fact, the two tsunamis you've just analyzed were the 2004 Indian Ocean Tsunami (Earthquake A) and the 2005 Nias Island tsunami (Earthquake B). When the tremendous shaking of the 2005 quake was felt, many feared it would generate another massive tsunami. In 2004 the IOT produced runups of 24-30 m. The Nias event, on the other hand, generated waves only 3 m high at most. Thinking back on this exercise, you should now understand why.