2022年日本福岛7.4级地震震害分析与对比

2022年3月16日在日本福岛县东部海域发生7.4级地震，本文基于近实时震害评估系统RED-ACT对此次地震进行了快速评估，包括强震动记录分析、区域地震破坏力震害评估结果和典型桥梁破坏，并结合实际震害对比了该系统评估结果以及其他主要震害快速评估系统的分析结果，结果表明：(1)此次地震造成的地面运动强度较大，多数台站记录PGA较2021年福岛7.3级地震更强，反应谱在0.5～1.3s区间呈现远高于2021年福岛地震的趋势。(2)RED-ACT的震害评估结果相较于日本NIED-CRS系统和美国USGS-PAGER系统与实际震害更为接近，在强震动记录较为密集的地区，开展基于强震动时程和建筑非线性分析的震害评估能够得到更为准确的震害评估结果。(3)此次地震对白石市附近桥梁造成了一定的破坏，桥梁破坏附近处的强震动会对典型桥梁结构造成一定程度的破坏。

Post-event seismic damage assessment of 2022 M7.4 Japan Fukushima earthquake and comparisons with field investigation

On March 16, 2022, an earthquake with a magnitude of 7.4 occurred in the eastern coast of Fukushima Prefecture, Japan. Based on the near-real-time regional seismic damage assessment system, namely RED-ACT, we conducted a prompt assessment of the earthquake, including the analysis of strong motion records, the seismic destructive power on a regional scale, and performance assessment of typical bridges subjected the typical ground motion of this earthquake. And the results are compared with other seismic damage assessment systems and filed investigation. The results show that:(1)The ground motion caused by this earthquake is relatively strong, and the peak ground acceleration(PGA)recorded by most stations is stronger than that of the 2021 Fukushima M7.3 earthquake, and the response spectrum in the period of 0.5-1.3 for some stations is much higher than that of the 2021 Fukushima earthquake;(2)Compared with NIED-CRS of Japan and USGS-PAGER of USA, the results of RED-ACT are closer to the actual earthquake damage. In areas with densely-distributed strong motion records, more accurate assessment can be obtained using seismic damage assessment method based on the strong ground motion records and nonlinear time-history analysis of buildings.(3)The earthquake causes certain damage to bridges near Baishi city, and typical bridge models will suffer some damage using the strong ground motions near the damaged bridge as input.