1. The power of earthquake is expressed in terms of magnitude on scale called Richter scale.
2. The destructive earthquakes have magnitudes higher than about 7 on richter scale.
3. Like many other scales, richter scale is not linear. It means that earthquake of magnitude 6 does not have the twice the destructive energy of an earthquake magnitude 3.
4. Infact, an increase of 2 in magnitude means 1000 times more destructive energy.
5. For example, an earthquake of magnitude 6 has thousand times more energy than earthquake of magnitude 4.