The Kursk submarine disaster that caused the sinking of the Oscar-class submarine (Russian: Project 949A Антей) Kursk took place during the first major Russian naval exercise in more than 10 years, in the Barents Sea on Saturday, 12 August 2000, killing all 118 personnel on board. Nearby ships registered the initial explosion and a second, much larger, explosion two minutes and 15 seconds later, which was powerful enough to register on seismographs as far away as Alaska. The Russian Navy did not recognize that the sub had sunk and did not halt the exercise or initiate a search for the sub for more than six hours. Because the emergency rescue buoy had been intentionally disabled, it took more than 16 hours for them to locate the sunken ship.