def get_stddevs(self, C_SIG, stddev_types, num_sites):
        """
        Returns the standard deviations

        N.B. In the paper, and with confirmation from the author, the
        aleatory variability terms from the empirical model are used in
        conjunction with the median coefficients from the stochastic model.
        In the empirical model, coefficients for a single-station intra-event
        sigma are derived. These are labeled as "phi". Inter-event coefficients
        corresponding to two observed geothermal sequences (Soultz-Sous-Forets
        and Basel) are also derived. The inter-event standard deviation is
        therefore taken as the ordinary mean of the two inter-event
        sigma terms
        """
        stddevs = []
        intra = C_SIG['phi']
        inter = (C_SIG['tau_s'] + C_SIG['tau_b']) / 2.0
        total = sqrt(intra ** 2.0 + inter ** 2.0)
        for stddev_type in stddev_types:
            assert stddev_type in self.DEFINED_FOR_STANDARD_DEVIATION_TYPES
            if stddev_type == const.StdDev.TOTAL:
                stddevs.append(total + np.zeros(num_sites))
            elif stddev_type == const.StdDev.INTER_EVENT:
                stddevs.append(inter + np.zeros(num_sites))
            elif stddev_type == const.StdDev.INTRA_EVENT:
                stddevs.append(intra + np.zeros(num_sites))
        return stddevs
Returns the standard deviations

        N.B. In the paper, and with confirmation from the author, the
        aleatory variability terms from the empirical model are used in
        conjunction with the median coefficients from the stochastic model.
        In the empirical model, coefficients for a single-station intra-event
        sigma are derived. These are labeled as "phi". Inter-event coefficients
        corresponding to two observed geothermal sequences (Soultz-Sous-Forets
        and Basel) are also derived. The inter-event standard deviation is
        therefore taken as the ordinary mean of the two inter-event
        sigma terms