code: def _compute_faulting_style_term(self, C, rup):
          
          # ranges of rake values for each faulting mechanism are specified in
          # table 2, page 75
          return (C['a12'] * float(rup.rake > 30 and rup.rake < 150) +
                  C['a13'] * float(rup.rake > -120 and rup.rake < -60))
docs: Compute and return faulting style term, that is the sum of the second
          and third terms in equation 1, page 74.