tsunami facts

A tsunami (soo-NAH-mee) is one of the world’s most powerful and destructive natural forces.

They can speed across the ocean as fast as a jet plane, swallow up islands and wipe out villages.

But what causes tsuamis…? Join National Geographic Kids and dive into our tsunami facts to find out!

Tsunami facts

What causes a tsunami?

tsunami facts

Meaning “great harbour wave” in Japanese, tsunamis are sometimes called “tidal waves” but their strength has nothing to do with the tides. About four out of five tsunamis happen within the Ring Of Fire, a zone in the Pacific Ocean where earthquakes and volcanic eruptions frequently take place.

Giant slabs of the Earth’s crust, called tectonic plates, grind together. Sometimes, though, the plates get stuck, the pressure builds up and they suddenly slam into a new position. This causes an earthquake. If an earthquake lifts or drops part of the ocean floor, the water above rises and starts spreading across the ocean, causing a tsunami. Underwater landslides or volcanic eruptions can also displace water (cause water to spread across the ocean) and may lead to a tsunami.

How big is a tsunami?

tsunami facts

Out in the open ocean, tsunami waves are only about one-metre high because the water is deep. However, as the water becomes shallow, the waves slow down and begin to grow. They can rise 35m or higher – that’s the same as a 10-floor block of flats! 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 a fearsome 1,000km!

How fast is a tsunami?

tsunami facts

A normal wind wave travels at about 90kmh, but a tsunami can race across the ocean at an incredible 970kmh! Sometimes, before a tsunami hits, there is a huge vacuum effect, sucking water from harbours and beaches. People can see the ocean floor littered with flopping fish and other sea animals. Then a wave blasts onto the shore minutes later, then another and another for two hours or more. There may also be up to one hour between each wave.

tsunami facts

Can you predict when a tsunami is coming?

To save lives, scientists established the Pacific Tsunami Warning System, based in Hawaii, in the USA. Its network of detectors can track quakes that may cause a tsunami. These waves can race from one side of the Pacific Ocean to the other in less than a day, so people need to be warned in time to head for higher ground!

tsunami facts

What do you think of these tsunami facts? Let us know by leaving a comment, below!

Likes

LEAVE A COMMENT

THANK YOU

While you wait for it to be checked and approved why not to add a pre-selected message and a cool badge

WELL DONE,
YOUR COMMENT
HAS BEEN ADDED!

COMMENTS

  • henessey

    nice

  • nice

  • vanya.michel

    WOW

  • yah

    this was helpfull

  • WEJHFDUIHFBSDHGCV

    THIS A GOOD SITE I CANT BELEIVE THIS IS SOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO COOL

  • giraffe

  • Me

    This was awesome

  • AOGA

    THANKS SO HELPFUL :D

  • FOXY123

    So cool. how big was the meteor if it swept a wave around the earth SEVERAL times.

  • Yo mamas can dance

    This was helpful. Thank you.

  • bonbonfred

    thats kinda scary tho ;-;

  • big john

    thats pretty cool

  • mo

  • Luna

  • cool

  • i did not know this before

  • max

    cool

  • XxNight_flowerxX

    Scary!

  • kattie

    wow

  • Allie

    so much fun

  • Aadi

    I think the facts are cool.

  • Hello

  • poketodizzy

    cool lol wow

  • john

    cool

  • LOL!

  • ???

    Intresting

  • Avery

    That was cool.

  • scary

  • Matthew

    Thanks for the information. It really helped.

  • wow

  • nice

  • Abby

    amazing

  • bake1212

    fascinating

  • Macie McNulty

    It is great. Has awesome info

  • Thing 1

  • Toby

    cool

  • Cool

  • cool!

  • payge

    yay

  • reee

    Can't wait

  • ok i cant wait

  • Levi

  • Cool

  • zaniyah

    that was cool facts

  • Olivia

    that is amazing you guys are awsome LOVE YOU!!!!!!

  • jaelynn

    the tsunami is horrifying

  • Cartyc

    Those were some amazing facts

  • Brianna

    I want to know where around the world most tsunamis.

  • cs3378467

    cool

  • This is my absolute favorite site to search things on it gives so much good infoormation that lots of [peope need

  • Mia

    Gives some good information

  • John

    cool

  • Connor

    Cool

  • Madison

    I love this

  • KITTENS

    Hi this is cool

  • andrew

    tsunami are big

  • MJ

    HI HI HI HI

  • lEaH

    I am very interested. :)

  • Nice

  • wow

  • Kaydence

    Tsunami facts for life!

  • zack

    that toght me a lot i was taking notes

  • I LOVE TSUNAMIS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!