How Tsunami Warnings Fail, and How to Fix Them


The media is guilty of a pretty serious crime when is comes to tsunami warnings: confusing the public.

For an industry whose purpose in society is to provide clear, accurate information to as many people as possible, the media certainly had its ups and downs (see: Glenn Beck, Rachel Maddow, The Wall Street Journal, The New York Times, blogs, and the Chinese government for various interpretations on how to carry out this mission statement), but overall we try, and I’d like to think that people generally come out ahead in life as a result of our efforts.

The blame lies at least partly with scientists. According to Vasily Titov, director of NOAA’s Center for Tsunami Research, researchers like to use wave amplitude to measure the intensity of a tsunami. But according to an article by BBC News today, that can lead to a lot of misunderstanding about the dangers a tsunami poses to people living in its path:

“We’re scientists and we’re really proud of our models and our accuracy but we realized after the Chilean tsunami that when we convey this information to the public there is a gap between what we are saying and what is understood,” he told BBC News. “When we say there is a two-meter wave amplitude expected, the general person imagines a two-meter wall of water. But that’s not what amplitude means – tsunami would very rarely come as a wall of water. It refers to the amplitudes at tide gauges and it is peak to trough. It will not be the wave height that a surfer or someone on the beach sees.”

Tsunami modeling has gotten very precise, so much so that NOAA’s real-time tsunami forecasts were 80 percent accurate for the tsunami that coursed through the Pacific Ocean back in February (pictured above) following a magnitude 8.8 earthquake in Chile. But as Titov pointed out, a two-meter high tsunami would be barely noticeable coming ashore in Hilo Bay, Hawaii.

Instead it would manifest as an unexpected flood pushing inland from the sea.

So, how do we make the distinction? Instead of quoting wave heights, Titov suggests we change to treating a tsunami like a flood. Wherever computer models predict low-lying areas will be inundated, warnings and emergency responders should be targeting and getting people out.

To some extent, that’s already a rule of thumb for tsunami warnings — if you live in a low-lying area and a tsunami warning has been issued, leave. But this is more than just splitting hairs; accurately communicating risk to the general public will prevent unnecessary alarm when warnings are issued, and will lower the frequency of false alarms, which can save lives.

This is kind of a technical argument, and it could be argued that the failure in communication is scientists’ fault more than that of reporters and news anchors.

Still, it is the media’s responsibility to work to understand exactly what scientists are saying when they issue a statement about tsunami height. Contrary to all of the constant ill-informed yapping heard on cable news shows, blogs, and elsewhere, a journalist’s job NOT to merely parrot what scientists say, and take them at their word.

It’s our job to question what they say, and then to make it as understandable to as many people as possible.

Image: NOAA

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