Most earthquakes happen along the edges of Earth's big plates.
4 out of 5 of the world's earthquakes take place along the rim of the Pacific Ocean, a zone called the Pacific Ring of Fire.
Sometimes there are many small earthquakes before the big one. These small ones are called foreshocks. After the big earthquake, the mainshock, again there may be many small quakes. These are called aftershocks.
Aftershocks can follow an earthquake on and off for days or weeks.
An earthquake can last for just a few short seconds or go on for several long minutes.
Most Earthquakes last a minute or less.
Many earthquakes happen on the ocean floor. Big ocean waves can form after a quake resulting in a tsunami.
The shaking of the ground is not what kills most victims of earthquakes. The main killers in earthquakes are falling buildings, fires, landslides, avalanches and tsunamis.
The deadliest known quake in history shook China in 1556, taking about 830,000 lives.
Steel, reinforced concrete and wood are good building materials for an earthquake resistant house because they flex somewhat without breaking. Family homes built completely out of brick are not as safe because they can break apart easily.
An earthquake can trigger a volcano to erupt.
Each year, there are about a million earthquakes around the world. But only about 100 of these cause serious damage.
An earthquake happens somewhere in the world once every thirty seconds.
You may not notice a magnitude 2 quake.
You would feel the ground shake in a magnitude 3 quake.
A magnitude 7 or higher can destroy a city.
The largest recorded earthquake was a 9.5 quake in Chile in 1960.