Vulnerability of world cable communications

There is an ever present hazard of damage to the many thousands of miles of submarine cable resting on the floors of the oceans of the world. Damage may be caused by fishing trawl gear or ships' anchors, earthquakes, volcanoes, exploitation of sea-bed resources or deliberate sabotage. Such cables carry several thousand telephone conversations simultaneously, together with telex, telegraph and data signals. They are costly and difficult to repair, particularly in mid-ocean.
(D) Detailed problems