Tsunamis can’t be stopped, but if you can warn people that one is coming you can save a lot of lives, even if it’s only an extra few minutes. Currently, tsunami alerts are generated from seismic data, but even the fastest response based on the magnitude, location, and depth of the earthquake can be up to five minutes or more — too slow for the immediate at-risk vicinity. Buoy’s developed to measure sea pressure changes from tsunami waves can communicate the speed and size of a tsunami as it travels across an ocean basin and provide advanced warnings for those in its path, but again not for those who got hit by the wave before it hit the buoy. Which is why using the global positioning system (GPS) may be the best tool for getting the information about a tsunami out the fastest. How exactly? By measuring the ground deformation to the neighbouring shoreline caused by a large underwater earthquake. Those measurements can be used to figure out how much the seafloor has moved, and once you know that, it’s possible to calculate how big the tsunami will be and where it’s going, and do so in less than three minutes. Andreas Hoechner from the German Research Centre for Geosciences (GFZ) led the research, which looked at data from the 2011 earthquake in Japan. His team showed that a close look at the GPS data would have allowed geoscientists to get the word out three minutes after the shaking on the sea floor started — maybe less.
