Making Sense of Earthquake Early Warnings

Most people know about the earthquake early warnings issued on television and mobile telephones, but do you know how they work, or how accurate they are? Earthquake early warnings are a useful source of information just before the ground begins to shake, but they are also subject to limitations, such as accuracy and warning time. Many researchers at universities and the Japan Meteorological Agency are constantly working to address these limitations. At the time of the Noto Peninsula earthquake of January 1, 2024, 12 earthquake early warnings were issued in the space of one day. Those warnings were highly varied: some of them were issued as intended, others could have been handled better. This lecture offers a deep dive into the largely unknown world of earthquake early warnings, including their current status and prospects for evolution in the future.