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Earthquake Facts

Earthquakes can sometimes be really scary things, but they are very interesting in how they form and why they do.

Let’s take a look at all you need to know about earthquakes and fill your brain with knowledge!

Quick Earthquake Facts

  • About 500,000 earthquakes rock the planet each year, but we are not aware of them because they are too little or occur too deep down.
  • Seismic waves, a form of shock energy, move through the earth’s crust when earthquakes occur.
  • The world’s biggest earthquake, which was 9.6 on the Richter Scale, occurred in Chile in 1960.
  • Scientists use the varying velocities of the earthquake’s seismic waves to pinpoint the epicenter or point of origin of the quake.
  • An earthquake known as a foreshock happens prior to a bigger earthquake known as the main shock.
  • A further earthquake, known as an aftershock, happens after the main shock.

What is an earthquake?

Earthquakes are a sudden and quick shock of the Earth’s surface. 

earthquake facts

Earthquakes are actually a type of way that the Earth gets rid of some tension, just like you and I do, except we don’t rock the world.

Wow, this is quite something. More than a million earthquakes happen on Earth every single year.

Surprisingly they normally last for less than a minute, but can sure cause some damage.

tsunami warnings

Wouldn’t it be great if some brainy scientists created some sort of warning system that earthquakes were coming? Well, they do! In many places such as California and Japan, where earthquakes are common, the government lets the people of the country know when an earthquake is about to strike by sending mobile phone alerts.

In Japan, they even send alerts to your TV! This happens no matter which station you are watching. Very, very useful!

But who knows what the future might bring. If we knew they were coming we could prepare for them and they wouldn’t cause as much chaos.


What causes an earthquake and how do earthquakes form?

There are things called plates that run along the surface of the Earth. They are always moving about and pushing into each other.

This is a very slow process, but they do like to bump into each other a bit.

When they are moving around, sometimes they get squeezed or stretched. When this happens rocks form around the edges.

The rocks then move with humongous force and when this happens, we get an earthquake.

what causes an earthquake

When that force is big enough, the crust of the Earth literally breaks. When this break happens, that massive energy moves through the Earth. It’s almost like waves, but obviously a lot bigger. That is exactly what an earthquake is. 

What is a fault line?

Earthquakes are formed along fault lines. This is an area of stress in the Earth. At fault lines the rocks are sliding past each other and will eventually cause a crack in the Earth’s surface.

fault line

What are plate tectonics?

Plate tectonics are where continents move from one place to the next and they break apart as they move crashing into each other. This is another way that earthquakes are formed. 

These plates as they are called move in all sorts of directions and at different speeds too. Sometimes they collide or crash or pull apart from each other. This movement is what also causes earthquakes.  

What is a seismograph?

A seismograph is a machine that is used to measure the strength and the length of an earthquake. 


What is a tsunami? 


You might be wondering what in the world a tsunami has to do with an earthquake, well read on and find out more.

A tsunami is a large ocean wave which is normally caused by an earthquake that happens underwater or from a volcanic explosion.

They aren’t tidal waves but are actually caused from the forces of the moon and the sun and other planets in our solar system which affects tides.

moon earth size

Tidal waves are not only caused by the solar system, but they can also be caused by wind as it makes its way across the water.

You might have noticed when swimming in the ocean that with normal waves flow in a circular movement. Well a tsunami is quite a different thing altogether.

With a tsunami, the water flows straight, and this is what causes these frightening things to happen. It would not be cool to see a tsunami heading in your direction, you certainly wouldn’t be able to outrun it! 

tsunami wave

What is a Richter Scale?

Richter Scale

A Richter scale measures the strength of an earthquake. Each one-point increase on the scale indicates ten times the amount of shaking and 33 times the amount of energy.

The energy released by a large earthquake may be equal to 10,000 times the energy of the first atomic bomb. Wow, that’s unbelievable!

The most powerful earthquake ever recorded on Earth was in Valdivia, Chile.

It happened in 1960, and measured 9.5 on the Richter scale. That is one extremely massive earthquake!

Richter scale

When was the largest earthquake ever recorded in the US?

The largest earthquake ever recorded in the United States was the Great Alaska Earthquake on March 27, 1964. It had a magnitude of 9.2 on the Richter scale and lasted four minutes.

Can earthquakes change the day length?

Yes, large earthquakes can change the day length by altering the Earth’s rotation. When a massive earthquake occurs, the mass distribution on the Earth’s surface changes, which then causes the planet to rotate at a slightly different rate. This change in the planet’s rotation can alter the length of the day by a second.

Can we predict the Earthquake?

No, we can’t predict when the earthquake will happen, but scientists can estimate the probability of earthquakes in certain areas based on past seismic activity and geological data. Some systems can help to detect the earthquake in advance between a few seconds to some minutes. These warning systems use sensors to detect seismic waves and alert people in the affected areas.

What happens after the earthquake?

After an earthquake, there might be a chance of incidents like aftershocks, tsunamis, landslides, fires, and displacement.

What are tectonic plate movements?

What are tectonic plate movements

The greatest mountain ranges on earth are created by the movement of tectonic plates. The movement of tectonic plates is the factor for creating the mountain ranges on Earth. When two plates collide, one plate is forced downward into the mantle while the other plate is uplifted, creating a mountain range. This process is known as a convergent boundary.

The greatest mountain ranges on earth are created by the movement of tectonic plates. The movement of tectonic plates is the factor for creating the mountain ranges on Earth. When two plates collide, one plate is forced downward into the mantle while the other plate is uplifted, creating a mountain range. This process is known as a convergent boundary.


Examples include the Himalayas, Andes, Rocky Mountains, and the Alps. This process can take millions of years and is still ongoing in many parts of the world.

The Himalayas were formed as the Indian subcontinent collided with the Eurasian plate. 

The Andes mountain range in South America was formed by the collision of the South American plate with the Nazca plate.

The Rocky Mountains in North America were formed as the North American plate collided with the Pacific plate.

The European Alps were formed as the African plate collided with the Eurasian plate

Notable earthquakes in the US and earthquake-prone states?

Some notable earthquakes in the United States include the 1906 San Francisco earthquake, the 1964 Alaska earthquake, the 1994 Northridge earthquake, and the 2011 Virginia earthquake. 

The top 5 earthquake-prone states in the US are:

  • Alaska with      12053 Earthquakes
  • California with    4895 Earthquakes
  • Hawaii with        1533 Earthquakes
  • Nevada with         788 Earthquakes
  • Washington with   424 Earthquakes

Interesting Facts about Earthquakes

80% of the world’s earthquakes happen in the Pacific Ocean near Japan in a place called the ‘Ring of Fire’.

Sadly about 10,000 people die in earthquakes each year. Most of the deaths are when people are trapped in falling buildings.


Alaska has more earthquakes than any other US state.

They have had about 12,000 earthquakes in the last 30 years. Alaska is followed by California, Hawaii, Nevada, Washington, Idaho, Wyoming, Montana and Utah.

Woah! Now you know where NOT to live!

Related: United States facts


Now you are all ‘earth-quaked’ up and know how earthquakes form. One thing to remember is to stay out of their way if you can!

Have we left out any facts that you know?

Check out our other Earth Science facts!

Earth Science

layers of the earth cartoon

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