Earthquakes in Japan

Japan sits at the meeting point of four tectonic plates, the Pacific, Philippine Sea, Eurasian and North American, making it one of the most seismically active places on the planet. Along its Pacific coast the ocean floor is forced beneath the archipelago in vast subduction zones such as the Japan Trench and the Nankai Trough, storing the strain that is later released as major earthquakes.

The most exposed regions run down the Pacific side, from Tohoku and the Kanto plain around Tokyo to the coasts facing the Nankai Trough in the south. The magnitude 9.0 Tohoku earthquake of 2011 and its tsunami are the clearest reminder of that risk, and Japan responds with some of the world's strictest building codes and most advanced early-warning systems.