An earthquake is defined as the shaking or trembling of the earth caused by the sudden movement of rock.
Before we learn about seismic activity that has occurred in the West Texas region of the Chihuahuan Desert, let's review a little about earthquakes.
Most earthquakes occur along a fault, or a place where rock has moved on one or both sides of a crack in the earth. Most are too weak to be felt. Now and then, a major quake occurs that causes great damage.
Earthquakes are recorded on an instrument called a seismograph. Look at the picture below. As the earth moves below the seismograph, the heavy weight remains stationary.
