Question: what is the difference between a magnitude 5 and 6 earthquake?
Answer: The magnitude scale is logarithmic. That just means that if you add 1 to an earthquake's magnitude, you multiply the shaking by 10. An earthquake of magnitude 5 shakes 10 times as violently as an earthquake of magnitude 4; a magnitude-6 quake shakes 10 times as hard as a magnitude-5 quake; and so on.