A New Method of Quickly Estimating Epicentral Distance and Magnitude from a Single Seismic Record

<b>Improved Algorithms of Seismic Parameters Estimation and Noise Discrimination in Earthquake Early Warning</b>

“…The B coefficient is then obtained by quantifying the amplitude growth rate of the initial P-wave. This technique is called the B-Δ method [4]. However waveforms arriving just after the P-wave do not depend on magnitude, i.e.…”

“…Since P-wave propagation velocity is faster than S-wave, P-wave information is an effective source to stop trains rapidly. Japanese railways are equipped with systems which employ seismographs capable of automatically issuing P-wave warnings [4,5,6]. The seismographs used for this earthquake early warning (EEW) system detect arrivals of P-wave, and then estimate seismic parameters, such as epicentral distance, back-azimuth and seismic magnitude, from passing P-wave waveform information.…”

Earthquake Early Warning System for Railways and Its Performance

“…To estimate the epicentral distance, the B-Δ method 7) is applied. This approach allows estimation from the empirical relationship between epicentral distance and an increasing ratio of acceleration of the initial P-wave ( Fig.3(a)).…”

The Status of Earthquake Early Warning around the World: An Introductory Overview

“…Then, a similar scaling between the amplitude of the S-wave displacement and magnitude is used (Kamigaichi 2004). The epicentral distance, which is necessary to translate the maximum amplitude value into magnitude, is estimated by using the first two seconds of the log-transferred P-wave envelope slope (B-delta method; Odaka et al 2003).…”

“…First, the location is estimated. Using a single P-wave detection, the slope of the onset is translated to epicentral distance, and the azimuth is estimated by fitting an ellipsoid to the particle motion (Odaka et al 2003). In addition, when one or two stations have detected a P wave, a "territory" region is defined where the event must have occurred based on the fact that other stations have not yet triggered (Horiuchi et al 2005).…”