Earthquakes

Question

The magnitude of an earthquake is a measure of the amount rof energy released.of magnitude 6 releases about 30 times as much energy as an earthquake of magnitude 5. The magnitude of the 1989 earthquake in Loma Prieta, California, was about 7. The magnitude of the 1933 earthquake in Sanriku, Japan, was about 9. Simplify 30^9/30⁷ to find how many times as much energy was released in the Sanriku earthquake.

Answer 1

This question is an exercise in powers of 10.

 

The rule is a^m/bⁿ = (a/b)^{m - n}

 

in this case 30⁹/30⁷ = 10²

 

so the earthquake was about 100 times more powerful