Go to: Introduction Although National Oceanic and Atmospheric Administration scientists at the Pacific Tsunami Warning Center in Hawaii issued tsunami warnings as soon as they heard of the huge earthquake off Sumatra, the waves outran communications at jet speeds of 500 mph (804 kph) - catching hundreds of thousands of people unaware. Here is a timeline of the agency's actions soon after scientists learned of the giant earthquake. All times are Greenwich Mean Time, on Sunday, December 26, 2004. Source: NOAA