The thing that protects global information traffic is the fact that there’s some redundancy built into the system. Since there is more cable capacity than there is traffic, when there is a break, information is automatically rerouted along other cables. Because there are many systems linking to the United States, and a lot of internet infrastructure is located here, a single cable outage is unlikely to cause any noticeable effect for Americans.

http://theconversation.com/in-our-wi-fi-world-the-internet-still-depends-on-undersea-cables-49936