# Question #32c5c

##### 1 Answer

Mar 8, 2016

The Richter Scale used for earthquake magnitude is a logarithmic scale.

#### Explanation:

That means each step change indicates an increase in magnitude of 10 times. From 5 to 6 is one step change, or 10 times as much. A second change to 7 would be another 10 times as much, so the energy difference is 10 * 10 = 100.

From the available answers, the "approximate" one would be c) 90.

Figure from http://www.seismo.ethz.ch/eq_swiss/Ursache_Erdbeben/index