P波最大加速度を用いた新たな震度予測手法の提案

Abstract

The Japan Meteorological Agency has started to provide the Early Earthquake Warning (EEW) since October 2007. EEW is expected to reduce earthquake damages by informing people about estimated seismic intensity before arriving strong motions. However, EEW has some problems, such as low accuracy and/or strong motions arriving before EEW information near the near-source area. In this study, we propose new method to estimate seismic intensity more accurately and rapidly by using P-wave Magnitude (Mp) which is defined by maximum P-wave acceleration of vertical component, although JMA magnitude is defined by maximum S-wave displacement. Attenuation formula of P-wave maximum acceleration derived from seismic records and estimation relationship between seismic intensity and P-wave maximum acceleration were also proposed in this study. By using these empirical equations seismic intensity in a target site can be estimated P-wave information. The method is also able to apply as onsite alarm system. It is showed that the new method proposed in this study has well accuracy and is useful technique for real time earthquake emergency information.