Types of earthquake

Earthquakes come in many different forms, each happening for special reasons deep inside the Earth. Understanding these types helps scientists predict and prepare for them better. The main kinds of earthquakes include tectonic, volcanic, and collapse earthquakes, each linked to different geological activities.

Tectonic earthquakes are the most common and powerful. They happen when huge blocks of the Earth's crust, called tectonic plates, shift suddenly. This movement releases energy that travels through the ground as shaking . These earthquakes often happen along fault lines, where plates meet .

Volcanic earthquakes are smaller and happen near active volcanoes. They occur when magma moves underground, causing the rocks to break . These quakes often happen before a volcano erupts, giving scientists clues about possible eruptions.

Collapse earthquakes are rare but can be very dangerous. They happen in underground areas that have been hollowed out, like old mines or tunnels. When the roof of these spaces can no longer support its weight, it collapses, causing the ground above to shake suddenly .

Studying the different types of earthquakes helps us understand Earth better and teaches us how to stay safe when the ground moves.

A

An aftershock is a smaller earthquake that happens after a bigger one, usually in the same place. It’s like a quick follow-up shake that comes after the main earthquake.

Main article: Aftershock

B

A Blind thrust earthquake is a special kind of earthquake that happens along a thrust fault. What makes it unique is that this type of earthquake does not show any signs on the Earth's surface, meaning you might not see any cracks or changes in the ground above where the earthquake occurs. These earthquakes can still be powerful even though they are hidden below the surface.

Main article: Blind thrust earthquake

C

Cryoseism is a type of seismic event that happens when frozen soil or rock suddenly cracks. This can occur when water or ice inside the ground quickly freezes or thaws, creating a shaking effect similar to a small earthquake.

D

A deep-focus earthquake, also known as a plutonic earthquake, occurs at a depth greater than 70 kilometres or 43 miles below the Earth's surface. These earthquakes are less common than those closer to the surface. Another type is the doublet earthquake, which happens when two or more major shocks of almost the same strength happen close together in time.

E

Earthquake swarm happens when one area has many earthquakes happening close together in a short amount of time. These smaller quakes can sometimes be felt, but they usually aren't as powerful as bigger, single earthquakes.

F

A foreshock is a smaller earthquake that happens before a bigger one, called the mainshock. It occurs in the same area and time period as the larger earthquake, giving scientists hints that a bigger quake might be coming.

H

Harmonic tremor is a continuous shaking of the ground that happens when magma moves underground or when volcanic gases are released from magma. It is often linked to volcanic activity.

I

There are different types of earthquakes based on where and why they happen. Induced seismicity refers to smaller quakes caused by human actions that change pressure on the Earth's surface. Interplate earthquake happens where two tectonic plates meet and move against each other. Intraplate earthquake occurs inside a single tectonic plate, away from its edges.

M

A megathrust earthquake is a very powerful earthquake that happens at places called subduction zones. These zones are where two pieces of Earth's outer layer, called tectonic plates, push together. One plate moves under the other, which can cause the ground to shake a lot. These earthquakes are some of the strongest that can occur on Earth.

Main article: Megathrust earthquake

R

Remotely triggered earthquakes happen when the energy from one earthquake affects areas far away. These earthquakes are not in the same location as the original quake or its aftershocks, showing how powerful seismic waves can travel through the Earth.

S

There are several special kinds of earthquakes. A slow earthquake happens very slowly, lasting from hours to months, instead of just seconds or minutes like most earthquakes. A submarine earthquake takes place deep under the ocean where water covers the ground that shakes. Some earthquakes, called supershear earthquakes, break apart so fast that they create a loud sound similar to a sonic boom. Finally, a strike-slip earthquake happens when two parts of the Earth’s crust slide past each other in opposite directions.

T

A tsunami earthquake is a special kind of earthquake that causes a tsunami much bigger than what you would expect from the earthquake's size when measured by certain seismic waves. These earthquakes happen underwater and can create very large waves that travel across the ocean.

V

A volcano tectonic earthquake happens when magma moves underground. This can occur when magma is injected into or withdrawn from the Earth's crust, causing the ground to shake. These earthquakes are usually small and happen near active volcanoes.

Main article: Volcano tectonic earthquake