Aizuno Abyssal Vortex

The Aizuno Abyssal Vortex is an immense and anomalous subsurface ocean current on the Imperial Oceanic Ice-7 Moon of Aizuno. Located below the depth of 6-miles and descending an unknown distance, the true extent and origin of the immense current is largely unknown.

History
Following the successful terraformation of Aizuno by 2825 a large influx of colonists moved to the newly habitable world, first establishing small colonies on the water, but quickly growing these settlements into vast cities. With increased human habitation a desire to study their new home, and a growing military interest in protecting the vital world led to efforts to study and map the ocean currents beneath the worlds vast seas. Aizuno is an Ice-7 moon, meaning that beneath its deep oceans (Believed to reach somewhere around 200 miles down) the immense pressure causes the solidification of water into hot ice (Known as Ice-7).

Initial efforts to map the near-surface currents were successful, with the large but generally calm Circulation current, which flows from between one and half and three and a half miles deep, being fully mapped by 2835. Further around the same time the slightly more intense North Current was discovered. The North current originates from the north, as warm waters carried up by the circulation current sink beneath the ice cap glaciers, rapidly chilling and creating a southward current. The North current is nearly fully mapped and well understood, and is known to reach as fast as 9 MPH, and spans from four and a half miles to seven and a quarter miles at its deepest. However during this period many submarines which ventured toward the bottom of the North Current (From six and a half miles and deeper) disappeared for unknown reasons. The regular disappearances confused scientists, and spawned conspiracy theories throughout the colony.

Discovery of the Vortex
A current now known as the Aizuno Abyssal Vortex was finally discovered in 2860 when a submarine operated by the Aizuno Imperial Maritime Fleet was suddenly caught by an intense undercurrent at the 7 mile marker. Despite struggling against the current over the next minutes the submarine was pulled as deep as 10 miles before being freed of the current. The crew on board experienced only minor injuries.

The survival of the submarine's crew and their discovery of the Vortex sparked further interest in the study of Aizuno's currents and various organizations (Some independent, others funded by the various corporations of the moon and even the Empire of Galia itself) sought to measure and track the newly discovered current. Despite the increased interest, the Abyssal Vortex poised a significantly greater (And more dangerous) challenge. Unlike the Circulation or North currents, the Vortex is not calm or predictable, but rather has been recorded as being highly erratic and unpredictable, and to date no model has been able to consistently and accurately predict the flow of the current.

Further unlike the other currents, the Vortex is incredibly fast, averaging speeds in excess of 15 MPH, but it has been known to go as high as 20 MPH at times, nearly half the maximum speed of the average submarine rated for such depths. Additionally the Vortex exists from six miles deep and descends an unknown amount, meaning the pressures experienced at the top of the Vortex are already substantial, but even a few minutes of drop if taken from the top can plunge a vessel several miles down, even well beyond the standard safe range of 10 miles. The deepest any sub on Aizuno has ever submerged and survived in 11 miles, when a specialized vessel rated for 15 miles of depth attempted to descend before being caught in the current at 7 miles and plunged down 4 more until escaping the current and aborting the expedition.

To date there are no accepted explanations for the existence of the Vortex, and its true depth remains a matter of speculation. Few submarines venture below six miles for fear of being swept into crushing depths by the vortex, which poses a substantial barrier to the Aizuno Imperial Maritime Navy's defense plans for the moon and the Aizuno Imperial Shipyard orbiting it.