Acoustic intensities at receivers in a surface duct and in a deep submerged duct are calculated using a normal-mode theory. The sound source is in the surface duct, which is 60 m thick, and the calculations are repeated for thicknesses of the submerged duct ranging from 0 to 150 m, at frequencies from 160 to 400 Hz. Intensities in the surface duct at 400 Hz and above are not significantly affected by the submerged duct. As the frequency is lowered, the intensity decreases at a rate that varies inversely with the thickness of the submerged duct. The intensity in the submerged duct (in the shadow zone) is almost independent of frequency in the band between the cutoff frequencies of the two ducts; but decreases as the frequency is lowered past the smaller of the two cutoff frequencies.