There are large earthquakes and small earthquakes. Big earthquakes can take down buildings and cause death and injury. The study of earthquakes is called seismology. Seismology studies the frequency, type and size of earthquakes over a period of time.
When the earth moves offshore in the ocean, it can cause a tsunami. A tsunami can cause just as much death and destruction as an earthquake. Landslides can happen, too. This is an important part of the Earth's cycle.
Earthquakes are measured using observations from seismometers. The magnitude of an earthquake, and the intensity of shaking, is measured on a numerical scale. On the scale, 3 or less is scarcely noticeable, and magnitude 7 (or more) causes damage over a wide area.Contents [hide] 1 History
2 Causes of earthquakes
2.1 Earthquake fault types
3 Earthquake clusters
3.2 Earthquake swarms
3.3 Earthquake storms
7 Related pages
8 Other websites
The ancient Chinese also used a device that looked like a jar with dragons on the top surrounded by frogs with their mouths open. When an earthquake occurred, a ball fitted into each dragon's mouth would drop out of the dragon's mouth into the frog's. The position of the frog which received a ball indicated the direction of the earthquake. [change]
Causes of earthquakes
Main page: plate tectonics
Earthquakes are caused by tectonic movements in the Earth's crust. The main cause is that when tectonic plates collide, one rides over the other, causing orogeny (mountain building), earthquakes and volcanoes.