Yeah. I thought the point of being beneath the water, non cavitating propellers, anechoic coatings, was people not knowing where you were. Silly me.
The strategic value of having that information (two of our submarines are in the general area of the Philippines) is roughly equivalent to the strategic value of knowing that they are in the ocean somewhere generally. Knowing they are in the water is one thing, finding them another entirely.
To find a nuclear sub's exact location, one must have
(1) state of the art tracking capability below the water (sonar), and the ability to extract an ongoing series of real-time hits with sonar in order to plot a trajectory (course) updated regularly
(2) a drone or submarine of your own to assist in the tracking with sonar and that can maintain sufficient speed to keep up with the sub and the ability to follow it into deep water if it tries to evade by seeking out a trench.
(3) some approximate idea of where to START a systematic search that is more narrow than, "somewhere underwater within an area the size of Texas".
(4) reasonable certainty that the commander of the U.S. sub you are tracking (in this case the USS Michigan and another with tomahawk missile capabilities instead of ICBMs) will not consider your efforts to track and dog him to be hostile or decide to do anything about it like sink your vessel.