Were you shook up by the tremors centered in Virgina? Here are some things you should know about earthquakes.
1. Unsteady ground
An earthquake happens somewhere every single day. The U.S. Geological Survey (USGS) estimates that several million earthquakes occur in the world each year. Many go undetected because they hit remote areas or have very small magnitudes. The National Earthquake Information Center (NEIC) locates about 50 earthquakes every day, or about 20,000 a year.
2. The Richter Scale
Charles F. Richter developed the scale in 1935 as a mathematical device to compare the size of earthquakes. The magnitude of an earthquake is recorded by a seismograph. When an earthquake begins, the base of the seismograph shakes but a hanging weight does not. A spring absorbs all the movement. The difference in position between the shaking part of the seismograph and the motionless part is what is recorded, according to the U.S. Geological Survey.
3. History's mostRead More »from 6 Things You Didn’t Know About Earthquakes