Why do earthquakes occur?

Earthquakes are one of Earth'sdeadliest disasters, mostly because of their unpredictability and lack of prevention. But do you know why they happen?

Earth consists of several layers of different materials, the outermost of them being litosphere. It is made out of tectonic plates - huge pieces of rocks "floating" on top of mechanically weak layer - astenosphere. Because the asthenosphere is melting, it can float, moving tectonic plates with itself.

Position and movement of tectonic plates. Credits: https://www.space.com/earthquakes-facts-science

When two tectonic plates try to move past each other, friction stops them and builds up stress in between. Eventually, one slips, releasing vast amounts of energy and creating waves that travel through Earth. At one moment, those waves will reach the surface, causing shaking, which we call earthquake.

The biggest earthquake

The biggest recorded earthquake happened in 1960 in Valdivia, Chile. It had a magnitude of 9.5 degrees Richter. It caused the loss of 1655 lives, leaving 3000 injured. Around 2 million people lost their homes.

Title picture: https://pixabay.com/photos/earthquake-seismograph-seismic-wave-3167693/