code: def _get_distance_scaling_term(self, C, rval, mag):
          
          r_adj = np.sqrt(rval ** 2.0 + C["h"] ** 2.0)
          return (
              (C["c1"] + C["c2"] * (mag - self.CONSTS["Mref"])) *
              np.log10(r_adj / self.CONSTS["Rref"]) -
              (C["c3"] * (r_adj - self.CONSTS["Rref"])))
docs: Returns the distance scaling term of the GMPE described in equation 2