- Tsunami is a Japanese word that means "harbour wave"
- Earthquakes under the sea are the main causes of Tsunamis
- The biggest tsunami ever was at Lituya Bay, Alaska on July 9, 1958
- The earliest tsunamis were in Sicily 8,000 years ago
- Landslides and volcanoes can also cause tsunamis
A tsunami is a powerful series of waves caused by a disturbance underwater. This is usually an earthquake under the sea.
The waves travel through the ocean and cause devastation when they reach land. Humans are often killed and buildings destroyed when the water hits the coast.
To fully understand how tsunamis are caused we must have an understanding of tectonic plates, earthquakes, and finally, water.
What Is It?
Tsunami is a Japanese word meaning "harbour wave" that refers to a series of large ocean waves that hit a shoreline. The word originates from Japan because this is the country where tsunamis are most common.
These tsunami waves may be as long as 100km and travel across the ocean at speeds of up to 800 kmh. There may be a constant stream of waves that batter the shore for between 10 and 60 minutes.
Tsunamis are also known as tidal waves, due to their large and powerful nature. They have been depicted throughout history, art, television, and film as something terrifying, cataclysmic, and almost Armageddon-like.
Tsunamis are caused by sudden movements of the earth that happens under the sea. Often the most destructive Tsunamis are caused by earthquakes but causes can also include volcanic eruptions, landslides or even a comet hitting the sea.
Landslides cause tsunamis when the debris falls into the water. This has the same effect as dropping a large stone into a pool: big ripples are created. But when this happens in the sea and it is thousands of tonnes of rock and earth falling into the sea a very large ripple, more like a tidal wave is created. This travels across the sea until it comes into contact with land and a tsunami is formed.
Volcanoes cause tsunamis when there is an eruption. The volcano can either be on land or under the sea, in which case it is known as a submarine volcano. If the volcanic eruption happens on land, the tsunami is caused by debris and lava from the volcano flowing into the sea, which once again causes a bug ripple.
If the eruption happens underwater, the enormous power of the eruption sends shudders through the earth and disrupts the water. The water in the sea then breaks into waves which travel across the ocean until they come into contact with a coast. Here, a tsunami is formed.
How Do Undersea Earthquakes Start?
The most common cause of a tsunami is earthquakes. This is what caused the Boxing Day tsunami in the Indian Ocean in 2004 and it is also the reason behind the 2011 Japan tsunami.
To understand how earthquakes cause tsunamis we must first fully understand what causes earthquakes. Remember, tsunamis are an after-effect of an earthquake.
The earth sits on about a dozen tectonic plates. These are large floating pieces of hard rock that are constantly moving and fit together around the world like a jigsaw.
Undersea earthquakes happen when one of these plates is rubbing against another at a plate boundary. The two plates may become stuck as the heavier plate tries to slide under the lighter other. This causes a build-up of pressure in a process known as subduction.
As the heavier plate continues to slide beneath the lighter plate, it causes the lighter plate to bend downwards with the pressure. A point comes when the lighter plate can no longer take the intense pressure and suddenly snaps back up to the surface where it had been before.
The incredible force of the earth's plate shooting upwards in the water causes a huge rise in sea level. A vast body of water moves upward - like a huge mountain of water in the sea.
How Does a Tsunami Develop?
Everybody knows that what goes up must come down. This is particularly true for water which always likes to form a nice flat surface. So once the mountain of water has risen up the next step is for the sea to level itself out.
The mountain of water comes back down. This pushes the water that was underneath it outwards. The force of the water moves through the ocean causing an underwater force that travels for hundreds of Kilometres. The force of the water can reach speeds of up to 800 kmh as it surges through the ocean. The energy is underwater and is not noticeable on the surface.
As this force travels through the ocean it may eventually reach the shore. At this point, the sea becomes shallower. However, the energy in the water is still the same. The energy is compressed and the water is pushed upwards. This is how the energy is transferred from being underwater into waves on the surface.
- NOAA - National Oceanic and Atmospheric Administration
- USGS - U.S. Geological Survey
- PNSN - Pacific Northwest Seismic Network
Can Anything Be Done?
Unfortunately, nothing can be done to prevent Tsunamis. However, there are several organizations that use complex technology to monitor the movement of the earth's plates and sudden changes in water movement. There are also warning and evacuation procedures in place around countries like Japan and Hawaii where Tsunamis are frequent.
Any sudden earthquake that happens underwater will be detected in the same manner of an on-shore earthquake. These are measured in the Richter scale. If this is recorded then warning systems can sometimes be activated to evacuate people.
- Japan - March 11, 2011
- Indian Ocean - 26 December 2004.
- Papua New Guinea - 17 July 1998
- Sea of Japan - 26 May 1983
- Alaska British Columbia - 27 March 1964
- Chili - 22 May 1960
- Aleutian Islands - 1 April 1946
Read more about the biggest tsunamis in history.
Vaishnavi on June 11, 2020:
Thanks for this information
Pooja Garva on June 03, 2020:
Thank you very much for information...
Lucas Williams on May 02, 2020:
Great website helped me get an A.
Kumar Rathore on April 29, 2020:
Good information for tsunami
Natalie on January 25, 2020:
Thes irformations ar so nice
Lil Nugget on January 20, 2020:
Thank you it was very informative and I learned more about tsunamis and how tsunamis are formed.
littledude on December 09, 2019:
thx it helped me a lot
Gugue Ncube on December 05, 2019:
Thank u it help me a lot and l learned lot through reading these
Razzana ibrahim on December 03, 2019:
Thanks it help to completion of my project
kanishkaa on November 18, 2019:
thank you it helped me a lot
mic on November 14, 2019:
true facts and horable seens
Itzayana on November 11, 2019:
this was a good web cite would recemend
Keisha on November 05, 2019:
This is good facts about tsunamis because I watched a vdoi about tsunamis and it cause damage to the places where it happen
Tyfu on October 23, 2019:
Elena on October 22, 2019:
It us so good i used this for my homework thank u so much
Savith on October 10, 2019:
I want remedies
rosered on October 03, 2019:
i needed this for journalism,thank chu!^^
Danniela on September 23, 2019:
Super Duper thank you po kc ngawa kopo ang ass ko dahil d2 and godbless po.....
melody on September 09, 2019:
thanks it helped me in my project
saritha on August 09, 2019:
thanks it helped me in my project
omar on August 06, 2019:
this is going to help me loads
Ekansh Sahu on July 17, 2019:
THANK YOU SO MUCH!!
bigBoy on June 24, 2019:
Pandit on June 21, 2019:
bhai thanks for this excellent thing written by you
Lokesh Shah ,Kolkata ,WB, GREAT India on June 16, 2019:
Thank you sir for this great sharing of knowledge it helped me a lot in project assignment as well as my exams and my request is that again you write like this for topic weathering
And again thanks a lot sir
akm on June 15, 2019:
excellent . it was sooo helpful
Ashish on June 14, 2019:
Thanks ....it help in my project...Thanks a lot
harshvardhan on June 14, 2019:
very good job
Yogesh on June 14, 2019:
Good for my project
jassi on June 13, 2019:
thanks a lot
Ritwick on June 13, 2019:
Really good information....Thanks a lot for it......It helped me in my project.....Once again thanks
Rythm on June 07, 2019:
Was Good for my project
Thanks very good information on June 06, 2019:
Thanks very good information
Riya on June 05, 2019:
Thank u sooo much this helps me a lot
Devanjali on June 03, 2019:
it helped me for my project thanks a lot
Mrigank Mouli Mukherjee on June 01, 2019:
it helped me in my project
PIYUSH PANDEY on May 31, 2019:
Thank you for this! This is very helpful for me
JoJo Siwa on May 28, 2019:
This was very helpful, THANK YOU!
JJ on May 25, 2019:
I think this really helped me as Jenny said with my homework. Thanks Owlcation
Jenny on May 20, 2019:
Thanks it helped me in my project. But i need a little more information
Asim on May 16, 2019:
thank you for posting very helpful.
Sona on May 14, 2019:
Very good answer this helps me in my project, thank u so much
OfficialPewds on May 14, 2019:
I luv dis su moch thankyuo i needed thjs!!!!!!!!!
Shivangi on May 11, 2019:
Thanks a lot!
hannah on May 03, 2019:
wow that was so helpfull on my progect do thank you bec i had no idea what can cause a tsunami. : ]
MOMO on March 22, 2019:
Dearlove on March 08, 2019:
Sen. K on February 27, 2019:
Thank you soooooooooooooooooooooooooooooooooo much!!! I couldn't find a site with all this information until this!
It helped me lots with my school task!
Arti Gupta on February 19, 2019:
Yes this is a very simple way to ready my project
Tseries on February 19, 2019:
very good. also sub to pewds
Harini on February 04, 2019:
Thanks for the message
Man on January 08, 2019:
Reena mishra on January 06, 2019:
Thankyou for this information
ruchi singh on January 06, 2019:
yes , its very good it helped in my project .
so ya thanks..
aviral on January 03, 2019:
this thing helped me a lot. so, thanks
AAYUSHMAN RAI on January 02, 2019:
Thanx for the information about tsunami. It really helped a lot in my project work.
mmmmm on December 20, 2018:
Reee on December 07, 2018:
This really helped me out on my project
hajin lee on November 28, 2018:
kcrudu8297 on November 02, 2018:
it helped me on my project
Md.Mahabub Reza on October 11, 2018:
Mari on September 25, 2018:
Thank u very much
vritika on September 19, 2018:
Thanks for help..........
little blue on August 29, 2018:
thanxx a lot it helped me
little red on August 21, 2018:
thank it help me in my project
Lili-rose on July 24, 2018:
Thanks for the information!!!
Thanhha on July 15, 2018:
Very interesting.I hope you have more writting page
Neelam saini on July 14, 2018:
Thanks very much lts helps me in my project
Sachin sattavan 5757 on June 28, 2018:
I am very thank full of this information help in homework
Ikramudin on June 24, 2018:
It helped me in my project Thank You very much
PALLAVI on June 17, 2018:
nice and helped in my project of disaster i make disaster file first time in 9th class ,i have no idea but google and you tube help me in my project.thanksss
Warish on June 14, 2018:
Thannxxxxxxxxxxxxxxxxxx. It gives me many things
X loved on June 13, 2018:
it really really helped me for my CBSE class 10 Disaster Management project !!!!!!!!!! thank you very much. i hope many more informations related our studies will be posted in this way !!!!!!!!!!
harsh on June 03, 2018:
thanks it help me in my project,
swati on May 17, 2018:
Thanks. For information
nanddana on May 06, 2018:
this helped me a lot for my assignments...it is simply perfect. thank u
rayhan on April 28, 2018:
thx for the information :)
JSU on February 23, 2018:
Ashiq on January 11, 2018:
It helped me a lot thanxxxxxxx
Ritu on January 10, 2018:
it helped me a lot...... thank you very very very very very very very very very very much
Rob on December 28, 2017:
Wow I always wondered how they actually started so thank you very much. May God bless your soul and salude to this right now.
Luis on December 02, 2017:
Thanks good information
Amar on November 17, 2017:
its help me lot
Toukamawon on November 14, 2017:
It help me alot.
RMS123 on October 26, 2017:
this is helpful for a test :)
Marklyn on October 24, 2017:
Thankyou for the information.It helped me to complete my English research.
person on October 11, 2017:
thank for the info
Shreya roy on October 06, 2017:
Thanks a lot Ur help ......
Nikitha. G on September 18, 2017:
Thanks for giving nice information
brother on September 17, 2017:
excellent article /info
thank u guy
continue this bro
harsh on June 16, 2017:
this helped me a lot
NIKITHA on June 09, 2017:
VERY HELPFUL INFORMATION
THANKS A LOT
Aryan on June 09, 2017:
It is valuable thing for all the students to understand the concept of tsunami
shruti on June 07, 2017:
it really helped me thanks:)
Bhavs on June 05, 2017:
Yo bro this really helped me a lot :) You are a lifesaver
keep up the good work......
shambhavi on May 01, 2017:
Thanks this helped me a lot
Rishee Perera on June 25, 2016:
Thanks for this info. It really helped me
Jjjj on June 10, 2016:
Abc on June 06, 2016:
thanks it help me in completing my project...................................................
ranil vikas johar on November 07, 2015:
thanks alot for this information
i want to made my ppt by this information