Before revision: An EEW forecast (緊急地震速報( 予 報)) is issued to the National Meteorological and Hydrological Services when an earthquake of 3 or higher on the Japan seismic scale (or 3.5 or higher on the Richter magnitude scale) is expected, or when the amplitude of P- or S-waves measures more than 100 gals.
After revision: An EEW forecast (緊急地震速報( 預 報)) is issued to the National Meteorological and Hydrological Services when an earthquake of 3 or higher on the Japan seismic scale (or 3.5 or higher on the Richter magnitude scale) is expected, or when the amplitude of P- or S-waves measures more than 100 gals.