Find the magnitude of the 2nd earthquake

We don't do homework for you. However, how is magnitude calculated? Is it linear or logarithmic? Is a Richter 6 twice as strong as a 3?

Don't forget that the Richter scale is a logarithmic measure of shaking amplitude, not energy. So ... you will need to apply the fact that energy is proportional to amplitude raised to the 3/2 power. Post back with your answer to this problem and we'll check it for you.