On December 26, 2004, a series of devastating waves attacked coastlines all around the Indian Ocean, taking the largest toll of any tsunami ever recorded. The surges decimated entire cities and villages, killing more than 225,000 people within a matter of hours and leaving at least a million homeless.
This shocking disaster underscored an important fact: as populations boom in coastal regions worldwide, tsunamis pose a greater risk than ever before. At the same time, this tsunami was the best documented in historyopening a unique opportunity to learn how to avoid such catastrophes in the future. From home videos of muddy water engulfing seaside hotels to satellite measurements of the waves propagating across the open ocean, the massive influx of information has reshaped what scientists know in several ways.
For one thing, the surprising origin of the tsunamiwhich issued from a location previously thought unlikely to birth the giant waveshas convinced researchers to broaden their list of possible danger areas. The new observations also provided the first thorough testing of computer simulations that forecast where and when a tsunami will strike and how it will behave onshore. What is more, this event revealed that subtle complexities of an earthquake exert a remarkably strong influence over a tsunami's size and shape. The improved models that have resulted from these discoveries will work with new monitoring and warning systems to help save lifes.