Earthquake Early Warning System in Japan

Japan is situated in one of the most active areas in the world, where the Pacific and Philippine Sea Plates are subducting the Eurasian Plate and where stress and strain of the crust are accumulated (Fig. 1). This results in a lot of earthquakes, tsunamis and volcanic eruptions. As many as 50000 earthquakes are located in a year, among which 1000–2000 earthquakes are actually felt (Fig. 2). Some strike towns and cities causing destructive disasters. The Southern Hyogo Prefecture Earthquake (the Great Han-shin-Awaji Earthquake Disaster) was the worst earthquake disaster in the past 50 years with more than 6000 casualties. Therefore, efforts for prevention and mitigation of disasters caused by such phenomena have been continued as one of the most important national programs in Japan.