"Long-period ground motion" will be added to the Earthquake Early Warning

The announcement standards for earthquake early warnings announced by the Japan Meteorological Agency have changed, and from February 1, 2023 (Wednesday), the long-period ground motion class will be added to the announcement standards for earthquake early warnings.

Until now, earthquake early warnings have been announced based on seismic intensity predictions, but from February 1, 2023 (Wednesday), the predicted value of the long-period ground motion class will be added to the announcement standards and provided. , Earthquake Early Warnings will be issued even if a long-period ground motion class of 3 or higher is predicted.

[Class 3 or higher announced as an earthquake early warning]

Long-period ground motion refers to a large shaking (earthquake motion) that has a long period (the time it takes for the shaking to make one round trip) that occurs during a large earthquake.

[High-rise floors above the 14th floor, or buildings with seismic isolation structures]