[trigger (OP)]

Hi all, can anyone please tell me:  How many times greater is the maximum ground motion of a magnitude 7 earthquake compared with that of a magnitude 5 earthquake?

Many thanks trigger.

[dentstudent]

I think I'm right in saying that it's a log scale, and so a 6 is 10 times stronger than a 5, and a 7 is 10 times stronger than a 6; therefore a 7 is 100 times stronger than a 5.

As ever, Wiki has some good stuff....

http://en.wikipedia.org/wiki/Richter_magnitude_scale

[RD]

The Richter scale is a logarithmic scale (base 10),
 so the amplitude of the motion of a 7 is 100 times the amplitude of a 5   (7-5=2, 10²= 100).

[trigger (OP)]

Thank you so much for your help. I hope i can pick your brains again in the future