<b>Applicability of Magnitude Determination Method Considering Time Dependence of P-Wave Growth to Railway Earthquake Early Warning System</b>

Abstract

This article examines an earthquake magnitude (M) determination method to test its applicability for the railway earthquake early warning system. Although the effectiveness of the M determination method has been shown so far when multiple station approach is used, the railway system employs a single station algorithm considering immediacy of the warning. This study investigates if the M determination method can improve the performance of the system analyzing seismic records observed in Japan. As a result, the test demonstrated that the method speeds up the final M estimation without loss of accuracy, suggesting that the risks of running trains during an earthquake can be reduced by applying the new technique to the railway system.

<b>Improved Epicentral Distance Estimations for Railway Earthquake Early Warning</b>

“…To stop high-speed trains as soon as possible and minimize damage in the event of an earthquake, the Japan Railway earthquake early warning (JR EEW) systems, developed by the Railway Technical Research Institute, control trains based on P-wave information [1,2]. Seismographs dedicated to railway operations are deployed nationally to detect P-wave onset, and within seconds estimate the seismic parameters of epicentral distance, backazimuth and magnitude from single station information [3,4,5]. Since 2003, the JR EEW systems have estimated epicentral distance, Δ, using an empirical relationship, determined from recorded data, between the measured epicentral distance of earthquakes from single seismic stations and a parameter describing the amplitude growth rate of some period of the initial P-wave [3].…”