# Alaska experienced an earthquake of magnitude #8.7# on the Richter scale in February 1965. The earthquake in Indonesia in 2004 was #4# times as strong as the Alaskan one. So what was its approximate magnitude on the Richter scale?

##### 1 Answer

Feb 1, 2018

#### Explanation:

Assuming that

Hence the magnitude we are looking for is:

#8.7 + log(4^(2/3)) = 8.7 + 2/3 log(4) = 8.7 + 4/3 log(2) ~~ 8.7 + 4/3 * 0.3 = 9.1#