code: def _get_mean(self, C, mag, rake, dip, rrup, rjb):
          
          f1 = self._compute_magnitude_scaling(C, mag)
          f2 = self._compute_distance_scaling(C, mag, rrup)
          f3 = self._compute_faulting_mechanism(C, rake, dip)
          f4 = self._compute_far_source_soil_effect(C)
          f5 = self._compute_hanging_wall_effect(C, rjb, rrup, dip, mag)
  
          mean = (
              C['c1'] + f1 + C['c4'] * np.log(np.sqrt(f2)) + f3 + f4 + f5
          )
  
          return mean
docs: Return mean value (eq. 1, page 319).