20 Years Ago a Tsunami Killed 230,000 People. We Can Do Better Now.

On Dec. 26, 2004, one of the largest recorded earthquakes struck off the Indonesian island of Sumatra, heaving a piece of seafloor roughly the length of California about 36 feet sideways and 16 feet up. Some 6,000 aftershocks followed.

The tsunami that rose from this great shifting of tectonic plates reached over 115 feet in some places and ultimately killed about 230,000 people in Indonesia, Thailand, Sri Lanka, India, the Maldives and East Africa. If there had been a natural hazards misery index, it would have registered off the scale.

About one in 28,000 people on Earth perished that day because governments were ill equipped to warn residents and visitors about the coming wave and guide them to safe evacuation routes. India failed to warn people on its eastern coast even after the tsunami wreaked havoc in the Andaman Islands, hours before striking the mainland. In Phuket, Thailand, tourists who were mesmerized by the sudden withdrawal of water roamed the exposed seafloor and then were caught unaware by the rushing water. In the Maldives, men asked women and children to stay indoors, where they could not escape the flooding. The men climbed trees and onto roofs when they heard the roar, leading to a lopsided death toll.

Today people around the world are far likelier to receive a timely warning to evacuate a giant, dangerous wave. But as a Dec. 5 earthquake and (tiny) tsunami off Northern California showed, we can’t rely on just seismic information to generate warnings. That recent tsunami was only about two inches high by the time it reached the coast, but millions of people received a warning, triggering some to evacuate unnecessarily. A lot of the confusion would have been avoided if there had been more specific information for different locales, and this is entirely possible to provide.

In the 20 years since the Indian Ocean calamity, the Pacific Tsunami Warning Center started providing warning services to Indian Ocean countries. Scientists identified other high-risk zones around the world and modeled potential tsunamis. The National Oceanic and Atmospheric Administration, in conjunction with the United Nations, began training Indian Ocean scientists, emergency managers and sometimes even politicians in how to perform hazard assessment studies, do public outreach and produce inundation maps for evacuation planning and signage. The objective was to eventually provide targeted warnings and then update such warnings as new data comes in.

Before 2004, the Pacific had the only six tsunamographs in the world — buoys anchored to the deep ocean that detect tsunamis and transmit the information to satellites, which in turn transmit to tsunami warning centers. Now there are about 60 in the Pacific and the Caribbean and about 10 in the Indian Ocean. There are none in the Mediterranean.