Application of ElarmS to earthquakes in Japan

Earthquake Alarms Systems, or ElarmS, analyzes seismic waves in realtime for the purpose of providing rapid earthquake information and warning of damaging ground shaking. P-wave arrival times are used to detect and locate earthquakes, peak amplitudes and maximum predominant period of the initial P wave are used to estimate the event magnitude, and the estimated magnitude, combined with available observations of peak ground shaking, is used to predict damaging ground motions for the surrounding region. ElarmS has been calibrated using seismic data from northern and southern California. Here we both test and calibrate the ElarmS algorithms with seismic data from Japan's broadband networks. This provides a test of ElarmS in another geographical location and geological setting and also provides calibration of the algorithms for a substantial number of large magnitude (M>6) earthquakes.