How do tsunamis differ from other ocean waves?

Answer 1

wave anatomy 101The energy in a wind generated wave is usually half as deep as the wave height. This is why they diminish easily. There is not enough energy to push the water. They also generally have a wave length of a few meters at best. This is why they do not push on shore very far. A tsunami is caused by the up-lifting of the ocean floor in an earthquake at sea, and the energy fills the entire water column from the ocean floor to the surface. Tsunamis can have wavelengths of 100 miles or better and travel at speeds upwards of 500mph. As these waves enter shallow water, they slow at the leading edge, which causes the water following to "pile up". With the long wave length, this causes the water to come on shore for extended periods which causes the disaster.

Answer 2

Surface waves are caused by forces of wind and moving objects like boats/ships

Tsunamis are enormous waves caused by not so normal forces.

Forces can include:

Underwater explosive volcanic eruptions.

Earth being hit by an asteroid from outer space.

Earthquakes

Large masses of sediments moving from one place to another (down a hill under water)

It can possibly be "created" by underwater explosion of nuclear fusion or fission material. A tsunami created this way will not likely be of a devastating magnitude compared to when earth itself show its real power.

Answer 3

The major difference is this: A tsunami is caused by an underwater earthquake; a tidal wave is caused by the gravity of the moon.

More info:

People commonly refer to a "tsunami" as a "tidal wave," but this is incorrect: A tsunami has nothing to do with tides.

A tsunami is caused by any large displacement of the sea level, and a tidal wave is caused by the gravity of the moon and the sun.

The wavelengths of a tsunami differ from 5 minutes to an hour, and the wavelengths of a tidal wave differ from 12-24 hours.

The tides are not really a wave. They are a bulge in the level of the water due to the gravity of the moon primarily and of course since the earth is rotating that bulge will appear to move across the ocean. However, if you raise water by a certain amount and then let it subside it has to go somewhere. If this occurs in a bay or inlet where the rate that the water can flow back is restricted, then it will start to build up behind a wavefront as it tries to flow back but is impeded. This is called a tidal bore and these can be really large. Storm surges with hurricanes are similar. the water bulges up under the low pressure center of the hurricane and when that reaches land it pours onto the land as if the level of the ocean had risen. Combined with huge storm waves from the wind and also the fact that the wind can actually push the water in a given direction causing it to build up, this can be really devastating.

The quake raises the level of ground under the ocean, sometimes by many feet which pushes the water up and away. That disturbance then propagates away from the region and just corresponds roughly to an area where the height of the ocean is higher than normal. This may be a region of 20-30 miles or more. Now clearly if you are standing on the beach, the water will flow in to the point where the average height of the ocean is equal to the average height of the land. If the ocean suddenly raises its level by 3 feet, say, then the entire ocean will appear to flood in till it encounters the point where the land has risen by 3 ft on average. In some coastal areas this might be many miles inland. If the raising of the water was very violent as sometimes happens in a huge landslide or it encounters the same type of restrictions that I mentioned in the tidal bore, this is when we might see the classic Hollywood "tidal wave," but it is not really anything to do with tides.

Tsunami is the correct scientific term for a wave (or series of waves) caused by an earthquake, and coming onto land in an area relatively distant from the earthquake.

The wave action in the ocean is often hidden below the surface when in deep water and the full effect of the Tsunami may not be realized until it strikes land.

Answer 4

seismic sea wave means that the wave is caused by seismic activity and tsunamis can also be cause by meteorite impact...which is not a seismic event

Answer 5

a tsunami is just the really REALLY bigger version a ocean wave.

Answer 6

A tsunami is created by the movement of plates at the bottom of the sea; during an earthquake, the water is vibrating so much that a tsunami is formed.

Answer 7

A tsunami is usually triggered by an earthquake.