def _get_distance_term(self, C, rjb, mag):
        """
        Returns the general distance scaling term - equation 2
        """
        c_3 = self._get_anelastic_coeff(C)
        rval = np.sqrt(rjb ** 2. + C["h"] ** 2.)
        return (C["c1"] + C["c2"] * (mag - self.CONSTS["Mref"])) *\
            np.log(rval / self.CONSTS["Rref"]) +\
            c_3 * (rval - self.CONSTS["Rref"])
Returns the general distance scaling term - equation 2