This lesson introduces tsunamis, explains how they differ from ordinary waves and tides, and explores how people have understood them through history.
A tsunami is a series of waves caused by the displacement of a large volume of water, usually in an ocean or large lake. The water may be displaced by an earthquake, landslide, volcanic eruption, or another major disturbance. A tsunami is not a single wave: it commonly arrives as a wave train, a sequence of waves separated by intervals that may last from minutes to hours.
All flashcards
What is a tsunami?
A tsunami is a series of waves caused by the displacement of a large volume of water, usually in an ocean or large lake.
What generates ordinary ocean waves and tides?
Wind generates most ordinary ocean waves. The gravitational pull of the Moon and Sun produces tides.
Why is “tidal wave” a misleading term?
It implies a causal connection to tides, but tsunamis are generated by water displacement from major events, not by the gravitational forces that produce tides.
What does the Japanese word tsunami mean?
It literally means “harbour wave,” though tsunamis are not limited to harbours.
What did Thucydides suggest about tsunamis?
The ancient Greek historian suggested that submarine earthquakes could cause tsunamis.
Quiz questions
How can a major earthquake at a convergent plate boundary generate a tsunami?Answer: Sudden vertical seabed movement displaces the water above it.
What can generate a meteotsunami?Answer: Rapid changes in atmospheric pressure.
What does drawback describe during a tsunami?Answer: An unusual retreat of the shoreline when a trough arrives first.
How do tsunami intensity and magnitude differ?Answer: Intensity describes effects at locations; magnitude represents the event’s overall size.
What information do bottom pressure sensors provide for tsunami monitoring?Answer: Changes in pressure that indicate changes in the water column.
Based on the Wikipedia article Tsunami, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.