Study on relationship between strong motions and structural damage observed during the West off Fukuoka Prefecture earthquake

2005年3月20日，福冈西部海域发生7.0级地震，这是自1995年兵古县南部大地震以来，在大城市附近发生的第一次7级地震。有可能获得大量经得起统计分析的观测数据。结果表明：1)收集并分析了K-NET、KiK-net、JMA台网和福冈县台网等地震记录。然后，我们描绘了沿断裂面滑动（地震矩）的非均匀分布。在震源的东南方发现了一个单一的陡坡（强斑），该陡坡辐射出的强运动被沿克古断裂东侧较厚的第四纪层放大。2)在城市中心地区进行了广泛的建筑破坏调查，掌握了结构类型、层数和建筑年龄的破坏统计数据。我们还调查了其他类型的损害，如人身伤害、室内损害、液化损害和山体滑坡。研究发现，古古断裂带东侧建筑物的破坏比例较大，且较老的建筑物破坏更严重。我们还发现，室内的破坏很大程度上取决于楼层的数量。我们应该注意到，损坏主要发生在非结构部件，这可能有助于防止主要结构部件的进一步损坏。3)通过对假定的弦运动与观测损伤的比较，探讨了非线性响应分析模型的适用性。通过使用由兵库县南部地震期间的破坏建立的模型，我们发现计算出的破坏比率比观测到的要大得多，因此我们可能需要调整我们的预测模型以适应中等严重的输入

The West off Fukuoka Prefecture earthquake of Magnitude 7.0 occurred on March 20, 2005, which was the first earthquake of M7 class occurred near a big city since the devastating Hyogo-ken Nanbu earthquake of 1995. It is possible to obtain a lot of observational data that bears statistical analysis.We found:1) The seismic records of K-NET, KiK-net, the JMA network, and Fukuoka Prefecture network and others were collected and analyzed. We then delineate a heterogeneous distribution of slip (seismic moment) along the fault plane. We found a single asperity (a strong patch) located in the southeast of the hypocentet The strong motions radiated from this asperity were then amplified by thick Quaternary layers along the eastern side of the Kego fault2) The extensive building damage investigation was conducted in the central part of the city, and the damage statistics fur structural types, number of stories, and construction age has been grasped. We also investigated other types of damage, such as human injury, indoor damage, damage by liquefaction, and landslides. We found that the damage ratio of buildings is larger in the eastern side of the Kego fault, and that older buildings had more serious damage. We also hind that the indoor damage depends strongly on the number of stories. We should note that the damage occurs mostly in a non-structural components, which may contribute to prevent further damage in the major structural components.3) By comparing a presumed strung motions with observation damage, we investigated applicability of the nonlinear response analysis model. By using the model established by the damage during the Hyogo-ken Nanbu earthquake, we hind that calculated damage ratios are tuned out to be much more than the observed and so we may need to tune up our prediction model for a moderately severe input