Earthquakes happen where plates in the Earth's crust meet.
When the plates get stuck there is a fault.
Earthquakes happen at these faults.
Most earthquakes happen under the sea.
The Earth's crust
The Earth's crust is not just one huge rock 'skin'. It actually consists of 20 pieces called 'tectonic plates'. Earth's hills and mountains were formed as these plates bumped into each other forcing the land to rise.
Causes of an earthquake
The tectonic plates are always moving. They usually slide past each other very very slowly, and the movement is not noticeable. If the edges of the plates get stuck, rocks bend and split, causing a fault, or a weakness, in the Earth's crust. Where the plates are stuck, pressure builds up, until there is a violent release of energy and the Earth shakes.
A building damaged by an earthquake. Getty Images
Most earthquakes occur under the sea. There are about 3000 earthquakes every day, many are so small that they are not noticed.
Volcanoes that are erupting can also cause earthquakes.
A road buckled and broken by an earthquake. ©iStock
Large earthquakes shake the ground and destroy buildings. People can be killed or injured, and gas and water pipes underground are twisted and can burst. Railway lines get buckled by the earthquake.
Measuring the strength of an earthquake
Scientists use instruments called seismographs (say size-mu-graphs) to measure the strength of tremors and earthquakes.
The Richter Scale, named after Dr. Charles F. Richter of the California Institute of Technology, is the best known scale for measuring the magnitude of earthquakes. The Richter Scale is the measure of the tremors.
The Modified Mercalli Scale measures the damage caused by an earthquake.
Earthquakes under the sea can start a tsunami that travels towards the coasts of nearby islands or countries, threatening the people who live there.
It’s a good idea to get information from more than one source!
Read more about earthquakes
https://businessconnectworld.com/2018/07/18/the-truth-about-earthquakes/
Read about the Richter Scale and the Modified Mercalli Scale:
http://www.geo.mtu.edu/UPSeis/intensity.html
Watch a video that explains how earthquakes happen
https://www.youtube.com/watch?v=hlePrsXTGxQ
