How do earthquakes happen

How do earthquakes happen?Did you know that surface of the Earth is not one giant shell? It may look solid to us, but the Earth’s surface has cracks in it, and actually fits together like a puzzle. What happens when one of these gigantic puzzle pieces moves? An earthquake! Big earthquakes occur with movement of about a meter or two. Small earthquakes happen with movements of millimeters.Scientists cannot predict when an earthquake will take place, but they do understand why Earthquakes happen.In many ways, earthquakes are one of nature’s reminders that we are living on the thin outer crust of a planet whose interior is still cooling.The ground may feel strong and solid beneath our feet, but the tectonic plates can move without our noticing.

Most earthquakes occur at the boundaries where the plates of the Earth’s outer layer meet. In fact, the location of earthquakes and the kind of ruptures they produce help scientists define the plate boundaries. Most destructive quakes, however, are caused by dislocations of the crust. The crust may bend and then, when the stress exceeds the strength of the rocks, break and “snap” to a new position.
Earthquakes may occur in an area before,during, and after a volcanic eruption, but they are not the cause or result of volcanic activity; rather they are the result of the active forces connected with the volcanic eruption.Earthquakes are always happening somewhere.Large earthquakes occur about once a year. Smaller earthquakes, such as magnitude 2 earthquakes, occur several hundred times a day.

Measuring earthquakes

Used on the surface of the Earth, a seismograph can measure the seismic energy, or magnitude, of an earthquake. It does this by making lines on a page when the Earth vibrates. Lots of wavy lines mean the earthquake was large; fewer waves mean the quake was small.
Magnitudes are recorded on a scale called the Richter Scale.The Richter scale is the best-known scale for measuring the magnitude of earthquakes. The scale begins at 3.5, which is the magnitude assigned to earthquakes we can barely feel, to 8 or greater which are the highest magnitudes. Magnitude 8 earthquakes can destroy cities.

How can I protect myself in an earthquake?

Most earthquake-related injuries and deaths result from collapsing walls, flying glass, and falling objects caused by the ground shaking. It is extremely important for a person to move as little as possible to reach the place of safety he or she has identified, because most injuries occur when people try to move more than a few feet during the shaking.