14:15 〜 14:30
[J04-3-04] Propagation of local undamped motion (PLUM) method and its improvement using P-phase discrimination for more rapid earthquake early warning based on wavefield-estimation approaches
The PLUM method, however, has room for improvement in rapid warning issuance since its prediction process rely only on strong motion by S phase and do not utilize P-phase information available before the S-phase arrival. We introduced a simple P-phase discriminator that uses V/H (ratio of vertical to horizontal components of acceleration) and modified the prediction process of the PLUM method. The modified method first conducts on-site prediction of S-phase strong motion for seismometers assumed to be observing P phase. After that, the modified method predicts strong motion for target sites in the same way as the original method. We applied the modified method to the Tohoku-oki earthquake and the Mj 6.5 and Mj 7.3 earthquakes in the 2016 Kumamoto earthquake sequence. Results showed that the modified method provided longer warning times by 5 s in the Tohoku-oki earthquake and 1 s in the Mj 6.5 and Mj 7.3 earthquakes, compared with the original method.