Practice!

Sample Problem

Find the intensity of the 2011 Japanese earthquake if its magnitude was 9.0 on the Richter scale.

Solution

On the Richter scale, the magnitude R of an earthquake of intensity I is given by R=log (I/Io), where Io=1 is the minimum intensity used for comparison.

9.0=log(I/1)

9.0=log(I)

109.0=I