A global approach to provide magnitude estimates for earthquake early warning alerts

We examine five different methods to estimate an earthquake's magnitude using only P wave data for use in earthquake early warning systems. We test two input parameters: the maximum predominant period of the P wave ((max)(p)) and the displacement amplitude of the P wave's vertical component (Pd). We apply our algorithms to 174 earthquakes 3.0<M<8.0 from California and Japan that have also been used in previous calibration studies. We also apply them to 1992 0.2<M<5.7 earthquakes that were processed by the real-time Earthquake Alarm Systems in California. We find that (max)(p) does not scale with magnitude for small earthquakes (M