Book-sized earthquake detector

Since Japan is such a hot zone for earthquakes, it is a no brainer that a Japanese company has developed a home-based earthquake detector that shares the equivalent dimensions of a paperback novel. It will connect to an early warning system network and data provided by Japan’s Meteorological Agency through the Internet, sending a loud countdown of 20 seconds whenever it detects a tremor. This should be ample warning for most able-bodied persons to turn off gas and fire sources while taking cover under tables. I wonder what happens when you’re stuck in a train during an earthquake – there’s nothing much you can do except pray for the best.