coulomb 3.3 software

I am using coulomb 3.3 software to study stress changes in Faults. After I open a given input file of a certain fault, they automatically calculate the seismic moment and shows it in Matlab window.Please anyone can help me to understand how they calculate it?

Answer 1

[Matthew Collins]

COULOMB 3.3 uses the empirical relationships decribed by Coppersmith and Wells (1994) to relate the surface area of the fault plane (A) to the moment magnitude (Mw). Using the area of the fault plane (A), the average coseismic slip (D) and the shear modulus (G), the moment magnitude (Mo) can be calculated as Mo = G*D*A. The shear modulus (G) for a linearly elastic solid can be calculated using the Young's modulus (E) and Poisson's ratio (v) from your input file, where G = E/[2*(1+v)]. The moment magnitude (Mw) and seismic moment (Mo) are related by Mw = (2/3)*log(Mo) - 10.7.