Predicting Tsunamis?

The world has certainly gotten smaller in some ways as global travel allows us access to more and more destinations. But just being able to get somewhere doesn’t mean we can control the weather, or the seismic activity. A powerful underwater earthquake struck the South Pacific on Tuesday, generating a devastating tsunami across the islands of American Samoa and Samoa. 

The magnitude 8.0 quake was followed by 29 smaller tremors throughout the region and spawned a series of four powerful waves that wiped out several villages, killing at least 89 people.

Though nowhere near as severe as the December 2004 tsunami that left over 200,000 people dead in the Indian Ocean, this latest quake-generated behemoth wave is a reminder of the volatility of the ocean floor in this part of the world. 

It also made me wonder, if we know that this part of the world is so prone to tectonic activity and the devastating waves it creates, can we do anything to predict it? It turns out that the answer is a qualified “yes”. Currently, scientists track tsunamis with surface instruments such as devices on buoys that record small changes in sea-surface elevation. However, this method is spotty, as it requires that a reader be placed in the correct location, which could theoretically be anywhere. Also, this type of detection provides very little advance warning because it detects the wave as it passes.

According to Science Magazine, in 2004 researchers as the National Oceanic and Atmospheric Administration (NOAA) realized that tsunamis could possibly be detected by monitoring the turbulence the waves create in the lower atmosphere. This type of activity can be measured using “side-looking” radars that can monitor an area with a radius of hundreds of miles rather than only at the location of the instrument. 

This theory was unwittingly corroborated by data from a satellite that happened to record atmospheric activity during the Sumatra-Java earthquake. Scientists are using this information to develop technologies that correlate the characteristics of the tsunami’s shadow with the size of the wave. Together, these developments would be “a powerful new tool…to improve the reliability of tsunami warnings” says Hawaiian seismologist Daniel Walker.

Unfortunately, technology this complex takes years to become operational. In the mean time, there is often little to no warning of an impending tsunami. On Tuesday, by the time the Pacific Tsunami Warning Center issued an alert the wave had already struck.For more information about recent earthquakes, preparedness or response click here. 

Photo: Fili Sagapolutele, AP via National Geographic; Map: Polynesian Cultural Center