On the afternoon of April 11, 2012, one of the most powerful
earthquakes ever recorded — and now revealed to be among the
weirdest — struck in the Indian Ocean, off the coast of Sumatra.
It's a region all too familiar with geological catastrophe.
Eight years earlier, in December 2004, the third largest
earthquake on record had ripped through a nearby region of the
ocean floor. The magnitude-9.1 earthquake and the monstrous
tsunami that soon followed killed more than 227,000 people in 14
countries. So when a magnitude-8.7 earthquake (some put the
magnitude at 8.6) shook the Indonesian island on that Wednesday
afternoon earlier this year, many expected the worst. Yet, no
monster wave appeared. A wave did come ashore, but it was a
miniature tsunami, just 12 inches (31 centimeters) high. All
told, the earthquake did very little damage — yet only five
higher earthquake magnitudes have ever been recorded. So what
was the deal? [Video: What Earthquake 'Magnitude' Means?] New
research published Sept. 26 in the journa