code: def _compute_distance_term(self, C, rhypo, mag):
          
          r_m = C["m1"] + C["m2"] * np.exp(mag - 5.)
          f_r = C["c2"] * np.log(np.sqrt(rhypo ** 2. + r_m ** 2.))
          # For distances greater than 50 km an anelastic term is added
          idx = rhypo > 50.0
          f_r[idx] += C["c4"] * np.log(rhypo[idx] / 50.)
          return f_r
docs: Returns the distance scaling term