What makes tsunami destructive?

What makes tsunami destructive?

Most tsunami damage and destruction is caused by flooding, wave impacts, erosion, strong currents, and floating debris (e.g., trees, structures, vehicles, and other things that can act like battering rams). The water can be just as dangerous, if not more so, as it returns to the sea, taking debris and people with it.

What determines the severity of a tsunami?

The speed and size of a tsunami is controlled by water depth. In the deep ocean tsunami waves may be unnoticed by ships or from the air. As the wave approaches land it reaches shallow water and slows down.

What determines the impact of a tsunami on a coastline?

The effects of a tsunami depend on the characteristics of the seismic event that generated the tsunami, the distance from its point of origin, its size (magnitude) and, at last, the configuration of the bathymetry (that is the depth of water in oceans) along the coast that the tsunami is approaching.

What determines how far inland a tsunami can travel?

Tsunami waves come up higher than normal waves and can rise 35m or higher. However, the scariest thing about a tsunami is its wavelength, as this determines how far inland it can travel. Whereas a large wave caused by a storm might have a wavelength of up to 150m, a tsunami could reach up to 1,000km.

Why do tsunamis become destructive as they approach the coast?

As the tsunami waves become compressed near the coast, the wavelength is shortened and the wave energy is directed upward – thus increasing their heights considerably. Just as with ordinary surf, the energy of the tsunami waves must be contained in a smaller volume of water, so the waves grow in height.

How do tsunamis originate?

Tsunami waves originate with the occurrence of a forceful vertical motion that causes the water column to fall or rise suddenly, comparable to the wave that is formed when a hand is plunged abruptly into water. Tsunamis are most commonly triggered by earthquakes that result from the motion of continental plates.

What is the difference between a distant tsunami and local tsunami?

Distant tsunamis are triggered in remote parts of the ocean whereas local tsunamis are triggered near the continents.

Why tsunamis cause immense damage to coastal areas?

Tsunamis cause immense damage to coastal areas as they are tidal waves triggered off by large underwater earthquakes which occur on the ocean floors and travel at a speed up to 800 km/hr.

How do tsunami waves travel?

Unlike wind-driven waves, which only travel through the topmost layer of the ocean, tsunamis move through the entire water column, from the ocean floor to the ocean surface. In 1964, tsunamis devastated coastal communities in Alaska.

How does a tsunami behave as it approaches land?

As a tsunami approaches land, the size increases The speed and size of a tsunami is controlled by water depth. In the deep ocean tsunami waves may be unnoticed by ships or from the air. As the wave approaches land it reaches shallow water and slows down.

Why are tsunamis so damaging near the shore but hardly noticeable out in the deep sea?

In the deep ocean, tsunami wave amplitude is usually less than 1 m (3.3 feet). The crests of tsunami waves may be more than a hundred kilometers or more away from each other. For the same reason of low amplitude and very long periods in the deep ocean, tsunami waves cannot be seen nor detected from the air.

Where do tsunamis occur?

By far, the most destructive tsunamis are generated from large, shallow earthquakes with an epicenter or fault line near or on the ocean floor. These usually occur in regions of the earth characterized by tectonic subduction along tectonic plate boundaries. The high seismicity of such regions is caused by the collision of tectonic plates.

What is the speed of a tsunami?

Tsunamis arrive at a coastline as a series of successive crests (high water levels) and troughs (low water levels)—usually occurring 10 to 45 minutes apart. As they enter the shallow waters of coastlines, bays, or harbors, their speed decreases to about 50–60 km/h.

Why do we study tsunamis in science?

Students can investigate tsunamis to discover the impacts of Earth’s systems on humans. Teachers can use these potentially deadly waves and other natural hazards to bring relevance to science concepts such as plate tectonics, acceleration and speed, force and motion, energy transfer, and the physics of waves.

Why do tsunami waves grow in height?

As the tsunami waves become compressed near the coast, the wavelength is shortened and the wave energy is directed upward – thus increasing their heights considerably. Just as with ordinary surf, the energy of the tsunami waves must be contained in a smaller volume of water, so the waves grow in height.