Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
A Tsunami is a series of giant ocean waves caused by a sudden disturbance under the ocean floor, such as an earthquake, volcanic eruption, or underwater landslide.
The word 'Tsunami' is derived from the Japanese words (meaning harbor) and (meaning wave).
In the deep ocean, tsunami waves have a small height (often less than ) but travel at very high speeds, sometimes exceeding .
As a tsunami reaches shallow coastal waters, its speed decreases, but its height increases dramatically, often reaching heights of or more.
A common warning sign of an approaching tsunami is the rapid receding of water from the shoreline, exposing the ocean floor.
Safety measures include moving to higher ground (at least above sea level) or moving at least inland immediately after an earthquake or tsunami warning.
Undersea earthquakes that cause tsunamis usually occur at subduction zones where tectonic plates meet, typically measuring above on the Richter Scale.
📐Formulae
💡Examples
Problem 1:
If a tsunami is detected away from the coast and it is traveling at a constant speed of , calculate how much time the coastal authorities have to evacuate the residents.
Solution:
Using the formula , we get
Explanation:
By dividing the total distance from the source by the speed of the wave, we find that the tsunami will reach the shore in hours.
Problem 2:
During a tsunami, a wave reaches a height of . If a house is built on a cliff above sea level, will the house be hit by the crest of the wave?
Solution:
Since , the house is above the peak height of the wave.
Explanation:
To ensure safety, the elevation of the safety zone must be higher than the maximum predicted wave height (). Here, the height of the cliff provides a safety margin of .