def get_mean_and_stddevs(self, sites, rup, dists, imt, stddev_types):
        """
        See :meth:`superclass method
        <.base.GroundShakingIntensityModel.get_mean_and_stddevs>`
        for spec of input and result values.
        """
        C = self.COEFFS[imt]

        imean = (self._get_magnitude_term(C, rup.mag) +
                 self._get_distance_term(C, dists.rrup, sites.backarc) +
                 self._get_site_term(C, sites.vs30) +
                 self._get_scaling_term(C, dists.rrup))
        # Convert mean from cm/s and cm/s/s and from common logarithm to
        # natural logarithm
        if imt.name in "SA PGA":
            mean = np.log((10.0 ** (imean - 2.0)) / g)
        else:
            mean = np.log((10.0 ** (imean)))
        stddevs = self._get_stddevs(C, len(dists.rrup), stddev_types)
        return mean, stddevs
See :meth:`superclass method
        <.base.GroundShakingIntensityModel.get_mean_and_stddevs>`
        for spec of input and result values.