Google Earth Bathymetry comes from Etopo global relief grids. They are made from satellite altimetry that measures the deformation of sea surface due to the gravity attraction with sea floor. This is not very accurate, but is the only way to obtain information there where no surveys have been made. Smith and Sandwell are the scientists who developed this methodology.

Where echo sounder data is available (Tracks and surveys) they use that data for interpolation in addition to coarse satellite data. http://topex.ucsd.edu/WWW_html/mar_topo.html
With this data they interpolate to 2 minutes grid (Etopo 2 ) this is about 2 nautical miles; 3.7 km. So square tiles of almost 4 x 4 km make the digital terrain model that you can see like a continuous surface.
When you interpolate dense, accurate, real (not so real, but that is little bit difficult to explain) echo sounder data, merged with coarse satellite data, that linear artefacts appear.
Smith and Sandwell are the main scientists in the development of this methodology.
http://www.bodc.ac.uk/data/online_delivery/gebco/documents/gridhelp.pdf

Of course not all lines are artefacts, as you can see, all ocean ridges are crossed by transform faults and many other linear features associated with tectonic margins http://seismic.cbsnews.google.neopolitan.com/cbs/earthquake_public.kml ). Hawaiian islands are in a line due to a hot spot beneath them etc. But when you see all that radius lines around an important harbour... those are artefacts.

So those lines are just an error in the model. It is not very suggesting but if you look it from another point of view, you will realize that is more mysterious in the sea bed morphology that even in Mars surface.

Thousands of people have been in the Everest, more than a thousand in the space but only 2 men (Piccard & Walsh) have been close to the deepest place on Earth. They stayed just for 20 minutes and they were far from putting their feet on there.