It's nothing, the Google version of the ocean floor is very very VERY weak representation, you will not be able to see any details, most likely they
are sonar tracks from various science ships, you can see those sonar tracks all over Google, the ocean bottom is a little more detailed in those sonar
tracks.
Cool looking stuff huh!! Love it too!! Hope this helps!
Great video explaining how sonar tracks can look like high intelligence made structures or are they just sonar tracks. Good Info if you watch the
video.
This is the site he was using in the above video
MGDS Marine Geoscience Data Center www.marine-geo.org...
On the other hand here is another video “with the exact place you are looking at in your posted pics” Some others thought it was unique also.
Maybe use the MGDS to closer check this area out & see what you can find out.
The specific area you are looking at doesn’t to me (no expert) look like the sonar tracks in the first video???
Here is another very educational & interesting & hopefully helpful link.
Exploring our Fluid Earth manoa.hawaii.edu...
Saunder is a trailblazer in underground bases research. He started with solid documents research- plans, budgets and infos on engineers' conventions
specializing in underground bases. Here's a video of his interview where he mentioned underwater bases for submarines: