Last Friday, the USS Roosevelt left Naval Base San Diego for deployment to "the @US7thFleet and @US5thFleet areas of operation," the US Pacific Fleet’s Twitter account announced October 10. The Seventh and Fifth Fleets operate within the western Pacific Ocean and around the Middle East, respectively.
— U.S. Pacific Fleet (@USPacificFleet) October 10, 2017
The Seventh Fleet’s domain of responsibility is far-reaching, "stretching from the International Date Line to the India-Pakistan border," an official told Yonhap, adding that the area of responsibility spans from "the Kuril Islands in the north" down to Antarctica. A carrier en route to join the Seventh Fleet will not necessarily be deployed anywhere near the Korean Peninsula.
During an early September visit to Seoul, US Pacific Fleet Commander Adm. Scott Swift promised to deploy a carrier strike group near the Korean Peninsula to demonstrate Washington’s "ironclad" commitment to South Korea’s security, according to South Korea’s Chosun Ilbo news daily.
"A dual-carrier operation in the region can be an option as well, given the strategic significance of aircraft carriers," Swift said at the time, per Yonhap.
The USS Ronald Reagan, the only forward-deployed US aircraft carrier in the region, is home-ported in Yokosuka, Japan, and serves with the Seventh Fleet.
In April, US Defense Secretary James Mattis said the USS Carl Vinson was on its way to either of the seas that bound the Korean Peninsula — the Yellow Sea or Sea of Japan – but US Navy officials in Hawaii were dumbstruck by Mattis’ statement. The Vinson was spotted thousands of miles away transiting the Sunda Strait between the Indonesian islands of Java and Sumatra about a week after Mattis said the Vinson was “on her way up there [toward the Korean Peninsula.]”