An earthquake is when the earths tectonic plates make a little and that's how an earthquake happens. An earthquake is measured on a Richter scale and to show how powerful it is. Most rare is an aftershock which only happens after an earthquake.A microquake is an earthquake that could be a sign of a bigger earthquake. sometimes a tsunami can also be caused by an under water earthquake .Earthquakes can range in size from those that are weak and cannot be felt by people and some so violent they can toss people around and can make a whole city collapse. The seismograph is used to measure how far or how long the earthquake is.in most general sense word earthquake is used to describe any seismic event-whether natural or caused by human-that generates seismic waves

One of the famous fault lines is in America in San Andreas.

Earthquake drill A map of earthquakes.

*Duck

*Cover

*Hold

Aftershock*A smaller earthquake, that happens after a larger earthquake.

Microquake*A microquake is the smallest measurable earthquake.

Ring of fire*The ring of fire is a ring of volcanoes and earthquakes.