A method of performing a fracture operation is provided at a wellsite. The wellsite is positioned about a subterranean formation having a wellbore therethrough and a complex fracture network therein. The complex fracture network includes natural fractures, and the wellsite stimulated by injection of an injection fluid with proppant into the complex fracture network. The method involves generating wellsite data comprising measurements of microseismic events of the subterranean formation, modeling a hydraulic fracture network and a discrete fracture network of the complex fracture network based on the wellsite data, and performing a seismic moment operation. The method involves determining an actual seismic moment density based on the wellsite data and a predicted seismic moment density based on shear and tensile components of the simulated hydraulic fracture network, and calibrating the discrete fracture network based on a comparison of the predicted moment density and the actual moment density.