How many times more powerful is an earthquake measuring 7.0 than one measuring 5.0?

The Richter magniude scale is logorithmic. As such the size (amplitude) of the largest seismic waves produced by a magnitude 7 earthquake are 102 (or 100) times larger than those produced by a magnitude 5 earthquake. However the amount of energy released by a magnitude7 earthquake is 1000 times greater (102)^3/2 than a magnitude 5 earthquake and so it is likely to be much more destructive.