The tsunami in northeastern Japan has taken the lives of thousands of people. Seismologist Jörg Lauterjung and his colleagues say the disaster could have been much worse if the country had no early warning system for events of this type.Lauterjung and his team developed a tsunami early warning system after disaster struck the coast of Sumatra in 2004. This system registered the earthquake and the tsunami that was generated off the Japanese coast, but the alarm was not triggered because the wave system had already weakened by the time it reached Indonesia. After some teething troubles, the system designed by the researchers in Potsdam is becoming established.