By Sid Perkins
Dec. 26, 2004 dawned calm in Southeast Asia, but things didn’t stay that way for long. At 7:59 a.m. local time, deep beneath the seafloor west of Sumatra, two of Earth’s tectonic plates began to slip past one another, releasing stress that had built up between the overlapping slabs for decades. An earthquake, the largest anywhere on Earth in more than 40 years, had begun.
The tip of the rupturing area quickly spread upward to the ocean bottom and then raced along the seafloor faster than a bullet shot from a rifle. Vast expanses of seafloor, along with the ocean above it, were thrust upward as much as 5 meters. Tsunamis raced away from the sudden bump in the ocean at jetliner speeds and crashed into coasts.