If you say ‘tsunami’ to describe those immense swells of water that can reach 100 feet in height, travel at more than 500 mph, and are capable of causing widespread destruction, then you are correct. This short video from the TED-Ed series explains tsunamis and how they work.
A tidal wave, by the way, is simply what happens when the tide comes in from a body of water. Because they are caused by gravitational interactions between the Sun, Moon, and Earth, tidal waves are predictable events. Check out the Department of Ecology’s description of Puget Sound tides.
Tsunamis, on the other hand, are unpredictable, and frequently caused by powerful earthquakes under the ocean floor. This type of earthquake pushes a large volume of water to the surface, creating waves that become the tsunami. The waves may be small in the deep, open ocean, but get much bigger and more dangerous as they approach shallower coastal waters. A tsunami also can be triggered by a volcanic eruption, landslide, or other movements of the Earth’s surface.
We cannot prevent tsunamis (or tidal waves, for that matter) but we can take precautions — and we should because the Cascadia Subduction Zone, where two large tectonic plates are rubbing together, lies just off our coast
DNR and its Division of Geology and Earth Resources work closely with the Washington Emergency Management Division, federal agencies, and local governments to prepare maps of recommended tsunami evacuation routes for many coastal Washington communities. Local and state emergency officials rely on maps of earthquake faults, tsunami inundation zones, and other information to plan their responses to earthquakes, tsunamis and other natural disasters.
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