Guest Author - LeeAnn OLeary

Did you know that well over 1,000 noticeable earthquakes shake our earth every year. So what exactly is an earthquake and just how often are they actually
occurring?

What causes an earthquake?

When parts of the Earth's crust moves earthquakes are the result. The Earth's outer surface is broken into plates as geologists refer to them. Anytime these plates move under or over each other or slide past each other an earthquake happens. Most earthquakes happen along the larger plates.

Recording earthquakes and the Richter scale
The first officially recorded earthquakes happened in the the late 1800s,
Earthquakes have a reputation throughout history for being a big force of natural destruction. Earthquakes are measured using a scale called the
Richter Scale. Earthquakes can be as small as 2.0 on the Richter scale. 2.0 earthquakes are not usually noticed as it is hard to feel a 2.0 earthquake. If an earthquake is less than 4.0 on the Richter scale it usually doesnt cause any damage. When an earthquake is 5.0 or larger on the Richter scale it can cause damage. An earthquake is usually considered strong when it is 6.0 on the scale.
When an earthquake is 7.0 it is strong and is called a major earthquake. The earth experiences thousands of earthquakes that are at least 4.5 or larger on the Richter scale every year. A 4.5 or larger earthquake has enough force to shake a building or a house. Earthquakes can be incredibly destructive - and sometimes even a minor earthquake can cause huge loss of life if it occurs in a populated city area. 8.0 earthquakes are very powerful. Each year one 8.0 earthquake happens on Earth scientists estimate.