Tsunami Facts for Kids

When an earthquake, volcano, underwater explosion, or a landslide happens under the water, it can trigger a tsunami. The waves can become disturbed in the ocean or in a large lake. When a tsunami occurs, there are large waves that are breaking waves and as the water level increases, it can cause flooding and violent damages.

Most tsunami waves are very large in weight and height and mostly happen on the coastline, causing damage, destruction, and even death.

Tsunamis Facts for Kids:

  • Underwater earthquakes can cause a tsunami
  • Tsunamis are triggered by landslides and volcanic explosions
  • On average, there are two tsunamis every year
  • Tsunami is Japanese for ‘harbor wave.’
  • Tsunamis occur mostly in the Pacific Ocean due to has a large number of active earthquakes
  • Out of five tsunamis, four of them happen in the Ring of Fire.
  • A powerful movement underwater can displaced water, sending shock waves in every direction.
  • The wavelength of a tsunami tells how far the tsunami will travel on the land.
  • Tsunamis are sometimes called tidal waves even though they have nothing to do with the tides of the ocean.
  • When there is more than one wave that happens during a tsunami this is called a wave train.
  • When a tsunami hits, the first wave might not be the strongest, bigger, and stronger waves might come later.
  • The DART or Deep-ocean Assessment and Reporting of Tsunamis is a warning system in the Pacific Ocean.

Why Do Tsunamis Cause So Much Damage?

Natural disasters like this cause so much damage because unlike normal waves that flow in circles, a wave from a tsunami moves the water in a straight path and this causes a huge wave.

They move very fast at around 475 miles per hour if the water is 15,000 feet deep.  If the water is 100 feet deep, it travels at around 435 miles per hour.

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How Do Tsunamis Form?

A tsunami is a succession of waves created in a body of water from an earthquake, landslide, meteorite impact, or volcanic eruption.

How Many Tsunamis Can Happen?

Japan a year on from devastation (2012)

Catastrophic events like a tsunami disaster happen on an average of twice a year. Every 15 years or so there seems to be a tsunami that’s larger and causes a lot of damage.

What Causes Tsunamis?

When an earthquake happens out to sea, a tsunami can follow.

With a strike-slip earthquake, which means an earthquake that goes horizontally, it causes 10% to 15% of the tsunamis that happen around the world.

With a vertical earthquake, there will be a bigger chance of there being a tsunami.

With a strike-slip earthquake, the only people that are usually affected by this are the people that live right near the water.

With a vertical earthquake tsunami, these cause more damage in more places.


What Does Tsunami Mean?

The word tsunami is a word that originated in Japan “tsunami” means “harbor wave.”

What Does a Tsunami Look Like When It Hits the Shore?

When a tsunami strikes a shoreline, it transforms. Moving from deep water and traveling into shallower water, it slows. But, as the tsunami’s speed weakens as it travels into shallower water, it gains height.

This shoaling effect causes the tsunami to grow and possibly reach several meters or more in height near the coast. The surge will appear as a fast-rising or falling tide, or a series of breaking waves.

How Can You Tell If a Tsunami is Coming?

  • Shaking of the ground close to the coast for more than twenty seconds.
  • If the water goes back into the sea suddenly.
  • Loud noises.
  • Booming sounds.

What Happens When There is a Tsunami?

Since tsunamis travel so fast, they can race across the ocean to land.

Sometimes, the ocean will behave like a vacuum and will suck the water from the shore and from beaches.

When this happens, people can see fish and other sea life just flopping because it happens so fast.

Then the wave will blast back to the ocean shore.  A minute later, another one can happen, and then another.  This can happen for over an hour.

Sometimes though, there is an hour between the massive waves.

Where Do Most Tsunamis Happen?

Most tsunamis happen where there are a lot of earthquakes and volcanoes that happen under the water.  This mostly happens in the Pacific Ocean.

Some countries that are close to the coast such as Chili, Japan, and the United States can all experience tsunamis.

Tsunami Memorial Kanyakumari

How Do Scientists Predict Tsunamis?

There is no way that a tsunami can be predicted.

Regions in tsunami danger zones have early warning systems in place to monitor earthquake activity and the hight of ocean waves this includes offshore buoys measuring wave height and lengths.

The Pacific Tsunami Warning System is in Hawaii and monitors eruptions and sends tsunami warnings if needed.

Having a tsunami alert system in place can advise people to evacuate if needed and reduce casualties.

A little History of Tsunamis

  • The Great East Japan Earthquake happened on March 11, 2011, it triggered a huge tsunami that flooded more than 200 square miles of coastland. Read more here
  • December 2004, one of the largest earthquakes ever recorded, happened just of the coast of Indonesia. This 9.1 magnitude quake triggered a tsunami that caused devastation around the Indian Ocean, killing over 228,000 people. Read more here
  • The 1958 Lituya Bay earthquake with a magnitude of 7.8 triggered a rockslide of 90 million tons into the narrow inlet of Lituya Bay, Alaska. The sudden displacement of water of so much water in a short space of time resulted in a megatsunami. Read more here

What Should You Do If a Tsunami is Coming?

If you are close to the shore and a tsunami is coming, you need to leave the area and find higher ground.

Can You Survive a Tsunami?

If a tsunami happens, here are some tips to follow:

  • Do not try to swim.
  • Try to find an object to hold on to and float on such as a tree trunk or a building.
  • Do not climb a tree because the weight of the wave can pull you down.
  • Do not run into buildings that are on the ground level because the tsunami can go inside buildings.

What Did You Learn?

  • What is a tsunami?  A tsunami is a massive wave that goes to the shore and is caused by earthquakes, landslides, or volcanic activity.  Tsunamis can be caused by things like landslides that happen under the water as well.
  • How fast can a tsunami move?  A tsunami can move even up to 475 miles per hour.
  • What are some signs that a tsunami is coming?  If the water goes away and fish are still laying there and animals begin acting weird, these are all signs of a tsunami.  Other signs are that you might hear a loud booming sound.
  • What is the difference between a tsunami and a tidal wave?  A tsunami happens because of natural things that occur like an earthquake or the shifting of plates where a tidal wave happens because of the rotation of the Earth, the sun, moon, and the tides.
  • Are tsunamis dangerous?  A tsunami can be very dangerous.  If you hear that a tsunami is coming, you need to find a way to get out of the area or to get to higher ground.