Earthquakes are caused by the movement of massive tectonic plates in the Earth's outer crust and mantle, which are the two topmost layers directly beneath the Earth's surface. The plates are huge, broken-off sections of rock, which move at an extremely slow rate. When the edges of moving plates bump against each other, sometimes they stick, while the rest of the plate continues to move. The fault area where the two plates collide causes an earthquake, because once the plates grind free, massive amounts of seismic energy is released, which shakes and rattles the ground.
Earthquakes are recorded with the use of a seismograph, which is a device that records the shaking caused by seismic waves. A seismogram is the recording made by a seismograph. It provides information about the distance of the earthquake from the location of the seismograph, and the earthquake's strength, which is measured on what is known as a Richter Scale. This scale is calculated using an earthquake's largest and most powerful seismic wave, and is expressed in magnitudes with a base of 10. For example, a magnitude 3 earthquake possesses 10 times the amount of ground shaking than a magnitude 2 earthquake.
Earthquake preparation is important for anyone who lives in a geographical area with previous earthquakes or fault lines. There are more than 500,000 earthquakes throughout the world ever year, and about 100 of those cause damage, according to Live Science. Prepare for an earthquake by knowing what room to gather in during an earthquake. Buy emergency items such as flashlights, blankets, dry food such as granola bars, bottles of water, battery-operated radio and first-aid kit. Keep these items in a place outside your home, such as in your car, so you can access them after an earthquake. Ensure that appliances such as water heaters are bolted to the wall.
Several myths, which are not supported by facts, have arisen about earthquakes. For example, many people believe in the existence of "earthquake weather," in which certain gloomy conditions augur the arrival of an earthquake. According to the U.S. Geological Survey, earthquakes occur equally in hot, cold and rainy weather, and there is not enough statistical evidence to associate dreary weather conditions with an earthquake. Another myth is that scientists can predict earthquakes, but the best they can do is make educated guesses about the likelihood of future earthquakes, based on past evidence. No scientist or organization has ever accurately predicted the date, time and location of an earthquake.