Unusual Mooring Oscillations: Apparent Foucault–Wheatstone Device in the Deep Ocean?

A pressure sensor, located for four months in the middle of a 1275 m-long taut deep-ocean mooring 2380 m water depth above seamount with sub-surface top-buoys and seafloor anchor-weight, demonstrates narrow-band spectral peaks deterministic well-predictable signals equivalent 0.5 amplitudes at uncommon sub-harmonic frequencies f*/4, f*/2, 3f*/4 local near-inertial frequency f* = 1.085f, where f denotes Coriolis parameter. None these sub-harmonics can be associated oceanographic motions, which are dominated by super-inertial internal waves that more broadband less predictable. No corresponding found spectra other observables like current velocity (differences), temperature, top buoy mooring. The mid-cable sensor was mounted on nearly 1 kN weighing non-swiveled frame. Its data hypothesized to reflect resonant mechanical oscillation high-tensioned elastic steel cable under repeated short-scale Strouhal vibrations induced vortex-shedding due water-flow drag and/or possibly tidal baroclinic motions about 50% larger near sloping than mid-depth thereby modifying mooring-cable helical shape. Cable dynamics mooring-motion considerations yield inconclusive results explain observations. Hypothesizing, observations suggest, dynamically, drainage helix-shape source non-tidal semidiurnal center-frequency (M2 + S2)/2 3f*/2, physically, measurement Earth rotation mimicking Foucault–Wheatstone device, and, oceanographically, relative vortex-rotation ζ/2 0.085f being interacting quasi-permanently nearby topographic obstruction, so total ζ/2.