> The locations of pretty much every cable laid in the last half century is very precisely tracked and one of the first things that has to happen when preparing a new cable route is to undertake a high resolution side-scan sonar survey of all or part of the planned route.
When the cables aren't well buried, they can migrate. No link, but earlier today I saw a description of a repair that was significantly delayed because the cable ends were 15 km away from where they were expected to be.
That said, I think there's a lot of area on the sea, and not a lot of cables, so chances of overlapping are low; especially if a survey is done of the new route immediately before. Although if they're buried, maybe you can't see them so well. And a little overlap here and there probably isn't a big deal, because most of the time cables are brought up, it's because they were severed, so likely it doesn't disturb the other cable too much on its way up.
When the cables aren't well buried, they can migrate. No link, but earlier today I saw a description of a repair that was significantly delayed because the cable ends were 15 km away from where they were expected to be.
That said, I think there's a lot of area on the sea, and not a lot of cables, so chances of overlapping are low; especially if a survey is done of the new route immediately before. Although if they're buried, maybe you can't see them so well. And a little overlap here and there probably isn't a big deal, because most of the time cables are brought up, it's because they were severed, so likely it doesn't disturb the other cable too much on its way up.