Isn’t there just something so comfortable about the solid ground under your feet? After all, part of the thrill of sports like ice skating and roller skating is the slightly out-of-control feeling you get when you’re sliding (or rolling) along.

But what if the ground under your feet wasn’t so solid? What if it moved and shook and tossed you about like a rag doll? That’s what some people experience from time to time when the earth under their feet shifts suddenly and unexpectedly. What are we talking about? Earthquakes, of course!

Although the ground seems extremely solid, it’s actually made up of gigantic pieces of rock that slowly, but constantly move. These pieces of Earth’s crust — what scientists call tectonic plates — collide with and rub against one another.

Every once in a while, the edges of tectonic plates will break or slip suddenly, releasing enormous bursts of energy in the form of earthquakes. In fact, earthquakes happen constantly, every day, all around the world.

Many earthquakes are just too small to be felt by our senses. However, the U.S. Geological Survey estimates that as many as 1.3 million earthquakes that can be felt by humans may occur each and every year!

Occasionally, large earthquakes will occur, releasing energy in the form of seismic waves more powerful than thousands of atomic bombs. When this happens, the results can be devastating. For example, a powerful earthquake off the coast of Japan in 2011 damaged thousands of buildings and caused the deaths of over 20,000 people.

Earthquakes have been around since the beginning of time. Scientists have really only begun to understand and measure them in the last 100 years or so, though. Today, scientists around the world use sophisticated seismic monitoring equipment to detect and measure earthquakes. One day, they may be able to use that information to predict when major earthquakes are likely to occur.

Scientists who study earthquakes — called seismologists — concentrate on areas of Earth’s crust where tectonic plates are moving in different directions. They call these areas fault lines. By studying fault lines, they hope to understand earthquakes better and learn to predict when they might occur.

Seismologists have learned that most earthquakes occur along established fault lines. Groups of fault lines combine to form fault zones. Some of the most extensive and active fault zones are given names, such as the San Andreas Fault in California and the New Madrid Fault that extends over 120 miles through several Midwestern states, including Illinois, Missouri and Arkansas.

48 Join the Discussion

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  1. when the earthquake starts does it mean that it’s going to rain?
    it might be about like the things that happend to the earth water in lakes and ponds

    • Hi Korean and Elijah, thanks for visiting us today! Sometimes it rains when an earthquake occurs, and sometimes it doesn’t! It all depends where and when the earthquake takes place, and how large it is. We’re glad you’re comparing earthquakes to tornadoes today, Wonder Friends! :)

    • Hi Jasmine and Xavion, sometimes earthquakes are so strong that multiple cities are affected. However, we haven’t had an earthquake that shook the entire world – thank goodness! We hope you’ll come back to Wonder with us again! :)

    • Great guess, Byancah-LaN’aye! This video shows a town that has had lots of earthquakes, Jasmine S! Have you experienced an earthquake where you live? :)

  2. So why or there really earth quakes???
    We’ll the next wonder is about a web surfer I surf the web all the time!!!

    • Thanks so much for WONDERing with us, Mrs. Gray’s 3rd Grade Class! It sounds like you are very prepared for an earthquake – and we’re glad to hear it! What a WONDERful connection! Come back and visit us soon! :)

  3. How come some places have more earthquakes than others? We don’t have many earthquakes here in NH and when we do they aren’t very strong. How come? We are wondering what was the biggest earthquake ever? and where and when?

    • Hi there, FES Second Graders! You have some WONDERful questions about earthquakes! There are locations in the United States that are known as active fault zones, such as California’s San Andres Fault. It’s a good thing you don’t have to worry about many earthquakes in New Hampshire! We hope you’ll keep WONDERing and researching earthquakes! :)

    • Hi Emily! Thanks for WONDERing with us! Places who lie on earthquake faults are know for getting more earthquakes. These places are all over the world, even California! Keep WONDERing! :)

  4. What tools do seismologists use to measure earthquakes? I live Along the San Andres Fault but I never seem to feel big earthquakes.

    • Hi Amy! Thanks for WONDERing with us! They have measurements within the ground to help measure. Many earthquakes do happen, but we can barely feel them! Keep WONDERing! :)

  5. So do seismic wave cause the aftershocks of an earthquake? If they do, does the power of the power of the seismic wave affect how far and powerful the aftershock will be?

    • Hi Madyson! Thanks for WONDERing with us! Tectonic plates do move! Have you heard of many earthquakes? Keep WONDERing! :)

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Have you ever wondered…

  • Whose fault is an earthquake?
  • How many earthquakes occur each year around the world?
  • What is a seismologist?

Wonder Gallery

dreamstime_xl_24165336 (Custom)dreamstime_xl_5846349 (Custom)dreamstime_xl_7158124 (Custom)after earthquakedreamstime_xl_29719718 (Custom)Vimeo Video

Try It Out

Did you feel that? It felt like an earthquake right here in Wonderopolis! If things are going to get shaky, grab the hands of several friends and family members and explore earthquakes with the help of the following fun activities:

  • What kinds of earthquakes have occurred in your state in the past? Are there areas of seismic activity you should know about? Find out more about the seismic history of your state by visiting the U.S. Geological Survey’s U.S. Earthquake Information by State/Territory website. Click on your state and follow the links to learn more about your area and the earthquakes it has experienced in the past!
  • Would you be prepared if an earthquake hit your city or state? What kinds of things might you need in case of an earthquake? Being prepared for a major disaster is a concern for the whole family. Check out these earthquake preparedness tips online and discuss them with your parents. Can you put some of the recommendations into practice? Do you have the items on hand that you might need in an emergency? It never hurts to put together an emergency kit with a few basic supplies, such as food, water, and a first aid kit.
  • Are earthquakes happening right now? You bet they are! Earthquakes occur continually around the globe all the time. To see what’s happening lately, visit the U.S. Geological Survey’s Realtime Earthquakes Map! Where is earthquake activity taking place right now? Can you use the map to figure out where the closest earthquake to where you live has occurred in the past week? Where was it? How far away is that? For a challenge, print out a blank world map and mark the locations of recent earthquakes using the data available at the USGS website.

Still Wondering

In Science NetLinks’ Earthquakes lesson, children examine how earthquakes follow the natural plate boundaries and how these boundaries help us predict where earthquakes are most likely to occur.

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