Why do so many of those transatlantic cables seem to land in New York?
Two Reasons: Geography and Routing
1) Geography: First, the Guardian's map is a little oversimplified. Most of those cables come ashore in Eastern Long Island or along a relatively narrow stretch of New Jersey coastline, about 50 miles south of NYC proper. They're in those places because of submarine geography. The sea floor isn't flat- there are mountains and canyons, etc. Ever tried to run network cable through a crowded office? Pain in the neck, right? Now imagine doing it with six-foot long tweezers and a blindfold...for 3,000 miles. The cable-layers pick the flattest, least cluttered path they can. In the mid-1950s, we started to get good sonar maps of the North Atlantic sea floor. Laying undersea cable is *expensive*, and there was a big burst of it as those maps started to take the guesswork (and a lot of the risk) out of the equation. And once a company found a good route, they tended to keep using it.
Seafloor mapping:
http://oceanexplorer.noaa.gov/explorations/03fire/background/mapping/mapping.htmlTimeline of transatlantic cables, 1951-2000:
http://www.atlantic-cable.com/Cables/CableTimeLine/index1951.htm2) Routing. A *lot* of information passes through those cables. It's compressed (Hoffman encoding, anyone?), and at each end you have to decompress it and then route it back into the land line system. This is a big, complicated operation (Much more so in the '50s and '60s when so many of the US-Europe cables were laid), and it's cheaper to add capacity by laying more cables between existing terminals than to build new ones.
Overview of cable topography & operations for one big cable operator, Apollo Systems:
http://www.apollo-scs.com/networktopology/Note that some companies (including Apollo) are starting to build new routes- the economics for doing that are getting better as cable gets cheaper and data traffic grows (shame on all the Americans downloading video files from peers in Sweden).
So yes, the undersea cable system *should* have much more redundancy, but it *won't* until somebody can make money building and selling that redundant capacity. And actually, these events will speed up that process; According to the Guardian, 50% of India's bandwidth is cut off. The people who own the pipes for the 50% that still works are having a *very* profitable week.