A vertical stack of alternately eastward and westward ocean currents below the thermocline within a degree of the equator. First discovered in the Indian Ocean, equatorial deep jets have been most extensively observed and described in the Pacific. There they have a dominant vertical wavelength of 300–400 m, and are most clearly seen at depths between 500 and 2000 m. The eastward and westward relative current extreme values may be superimposed on a larger vertical scale flow that may be either eastward or westward. For example, an eastward jet may appear in a given measurement as a relative minimum in a larger-scale westward flow. On a given longitude the depths of the jets vary interannually, but there is no clear evidence for steady vertical propagation.