1. The problem statement, all variables and given/known data The great Sumatra earthquake of late 2004 had a main shock with an M_w magnitude of 9.1 and a large aftershock in early 2005 had an M_w of 8.6. Calculate the seismic moment, M_o (energy release) of each earthquake. 2. Relevant equations M_w = 2/3*log(M_o)-6.0 Where log = log base 10. 3. The attempt at a solution This is really an easy calculation. Let's analyze the second earthquake. 3/2(8.6+6.0)=log(M_o) 21.9=ln(M_o)/ln(10) e^(ln(10)21.9)=M_o M_o = 7.943*10^21 N*m Now, if we convert it to dyne-cm, we times it by 10*7. So we get 7.943*10^28 dyne-cm. However, this report here: http://ceeserver.cee.cornell.edu/pll-group/doc/March_28_2005_Tsunami.pdf [Broken] States the answer should have been 1.1*10^29 dyne-cm Did I do something wrong in my calculation? Also note that there is serious issues with the equation. I have found many different values used instead of "6.0" and I have no idea which one is right. I am using the 'relevant' equation that I found in the notes/book.