Atlantic Tsunamis? |
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Tsunamis are giant, fast-moving ocean waves triggered by underwater events such as volcanoes, earthquakes, landslides, explosions, and impact of cosmic bodies such as meteorites. Tsunamis may reach the shore with a height of up to 30 meters, carrying tremendous amounts of energy. These waves can strip beaches of sand and vegetation, crush buildings, and cause flooding hundreds of meters inland from the coast. In May 2000, a group of researchers announced the discovery of cracks along the continental shelf off the Atlantic coast of Virginia and North Carolina. The cracks in the ocean floor on the continental shelf might indicate that the shelf is unstable. If large pieces of the shelf were to break loose, they would quickly slide down the continental slope, creating an underwater avalanche. This huge displacement of water and sediment could cause a tsunami along this stretch of the Atlantic coast — an area totally unprepared for this traditionally Pacific Ocean phenomenon.
Physics:
Students can explore the relationships between wave velocity, wavelength, and frequency in the Physics Explorer activity, Wave Behavior. (Requires Logal Express. Get a free trial subscription now.)
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Most
people are familiar with various "Earth
events" — earthquakes, volcanoes,
avalanches, hurricanes — that affect communities
around the world. What happens if one
of these events occurs under the ocean?
A
tsunami is a shallow-water wave, characterized
in deep water by extremely large wavelengths
(the distance between wave crests) and
small wave heights (amplitude). As the
waves approach the shore, the friction
from the increasingly shallow ocean floor
reduces the velocity of the wave. As the
velocity decreases, the wavelengths become
shorter and the amplitude increases significantly.
