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. It usually occurs in the same place. It is like a quick shake that follows the main earthquake.

Main article: Aftershock

B

A Blind thrust earthquake is a special kind of earthquake. It happens along a thrust fault. The special thing about this type of earthquake is that you cannot see it on the Earth's surface. There will be no cracks or changes in the ground above where it happens. 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 shaking that happens when frozen soil or rock suddenly breaks. This can occur when water or ice in the ground quickly freezes or thaws, making the ground shake like a small earthquake.

D

A deep-focus earthquake, also known as a plutonic earthquake, occurs far below the Earth's surface. These earthquakes are less common than those closer to the surface. Another type is the doublet earthquake. This happens when two or more big shakes happen close together in time.

E

Earthquake swarm happens when one area has many earthquakes close together in a short time. These smaller quakes can sometimes be felt, but they are usually not as strong as bigger 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 as the larger earthquake. Scientists can use foreshocks to guess that a bigger quake may be coming.

H

Harmonic tremor is a type of shaking that happens when magma moves underground or when gases come out from magma. It is often related to volcanic activity.

I

There are different types of earthquakes based on where and why they happen. Induced seismicity means smaller quakes caused by things people do that change pressure on the Earth’s surface. Interplate earthquake happens where two tectonic plates push against each other. Intraplate earthquake occurs inside a single tectonic plate, not near its edges.

M

A megathrust earthquake is a very strong earthquake. It happens in places called subduction zones. These are areas where two pieces of Earth's outer layer, called tectonic plates, push together. One plate moves under the other, and this can make the ground shake a lot. These earthquakes are among the strongest that can happen on Earth.

Main article: Megathrust earthquake

R

Remotely triggered earthquakes happen when the energy from one earthquake moves through the Earth and causes quakes far away. These new quakes are not near the first one or its aftershocks, showing how strong seismic waves can travel.

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. A submarine earthquake occurs deep under the ocean where water covers the shaking ground. Some earthquakes, called supershear earthquakes, break apart so fast that they make 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. It happens underwater and can create very large waves that travel across the ocean. These waves are bigger than you might expect from the earthquake's size.

V

A volcano tectonic earthquake happens when magma moves underground. This can occur when magma goes into or comes out from the Earth's crust, making the ground shake. These earthquakes are usually small and happen near active volcanoes.

Main article: Volcano tectonic earthquake