Accreting neutron stars ( NS ) can exhibit high frequency modulations in their lightcurves during thermonuclear X-ray bursts , known as burst oscillations . The frequencies can be offset from the spin frequency of the NS by several Hz , and can drift by 1-3 Hz . One possible explanation is a mode in the bursting ocean , the frequency of which would decrease ( in the rotating frame ) as the burst cools , hence explaining the drifts . Most burst oscillations have been observed during H/He triggered bursts , however there has been one observation of oscillations during a superburst ; hours ’ long Type I X-ray bursts caused by unstable carbon burning deeper in the ocean . This paper calculates the frequency evolution of an oceanic r-mode during a superburst . The rotating frame frequency varies during the burst from 4 - 14 Hz , and is sensitive to the background parameters , in particular the temperature of the ocean and ignition depth . This calculation is compared to the superburst oscillations observed on 4U-1636-536 . The predicted mode frequencies ( \sim 10 Hz ) would require a spin frequency of \sim 592 Hz to match observations ; 6 Hz higher than the spin inferred from an oceanic r-mode model for the H/He triggered burst oscillations . This model also over-predicts the frequency drift during the superburst by 90 \% .