A powerful magnitude-8.2 earthquake struck off northern Chile, setting off a small tsunami that forced evacuations along the country's entire Pacific coast.Five people were crushed to death or suffered fatal heart attacks, the interior minister said, but Chile apparently escaped major damage or serious casualties in the quake that struck last night.
Earthquakes involve the powerful movement of rocks in the Earth’s crust. The rapid release of energy creates seismic waves that travel through the earth.
Scientists use the different speeds of seismic waves to locate the epicentre (the point on the surface directly above where the earthquake originated) of earthquakes.
Seismometers are used to measure the magnitude of earthquakes. You are unlikely to feel a magnitude 3 earthquake but a magnitude 6 earthquake could potentially cause large damage.
The damage caused by earthquakes also depends on their depth and fault type.
The earthquake that hit the Tohoku region of Japan on March 11, 2011, had a magnitude of 9.0 and killed over 15000 people.
The most powerful earthquake ever recorded on Earth was in Valdivia, Chile. Occurring in 1960, it had a magnitude of 9.5.
It is important in earthquake prone countries such as Japan to build houses and buildings that react well to earthquakes. Good engineering practises can help stop buildings collapsing under the stress of large earthquakes.