Could be a S.A.D.M team on a black ops or another countries division using the coast as their drop off point. They use the water to dive then come up on land plant the NUKE which in the old days was a suitcase or backpack then they get back out via the water and disappear. They then use a mobile phone as the ignition device when the time is right. Don't wise to alarm you but maybe you could end up in a fall out zone shortly! They now use MicroNUKES which are the size of a coffeecup and don't have as big a radiation zone and also with normal equipment the radiation can't be detected because its of a different form. This happened in Bali, Taba, City of London, Iraq. Only United Snakes, Britain & IS-Ra-El have used these devices. The tyranists who always claim ever other MYTH are Tyranists or Terrorists.