Improving the understanding of Site-City Interactions for better earthquake risk mitigation (USCINT)

由于地震既不能预防，也不能预测，改善城市规划是减少对建成环境的破坏和人类损失的一个重要问题。如果考虑到已知发生在地震期间的短距离地面震动的可变性，城市地区的规划可能会得到显著改善。当地震发生时，除了浅层地质层中的波浪变化外，单体建筑物与土体的相互作用也可能导致地面震动的修正，从而增加地震危险性。在城市地区，这些相互作用不仅限于单个建筑与土壤之间的相互作用，还包括整个城市与土壤之间的相互作用。由于到目前为止还没有详细了解这些相互作用，所以在城市地区的规划和地震风险评估和缓解中没有考虑到它们。到目前为止，对这些影响的研究大多是通过数值模拟进行的，不可能将预测的地震波场与观测的地震波场进行比较。只有数量非常有限的分析试图基于经验数据集来解决这个问题。USCINT项目旨在通过使用独特的经验数据集和数值模拟来提高我们对地震过程中建筑物与土壤之间以及建筑物之间通过土壤相互作用的理解。更好地了解建筑物和土壤之间的相互作用可能有助于确定地震风险较高的地区，从而更好地预防地震。此外，这方面的知识可纳入城市地区标准风险评估和缓解办法的指导方针。最后，从长远来看，通过考虑土-结构相互作用和场地-城市相互作用效应来改进城市规划，有助于降低地震风险。

Since earthquakes can neither be prevented nor predicted, improving the planning of urban areas is an important issue to reduce damage to built environment and human losses. Planning of urban areas may be significantly improved if the variability of ground shaking over short distances that is known to occur during earthquakes is taken into account. When an earthquake occurs, besides the alterations of waves in the shallow geological layers, the interactions between single buildings and the soil might also contribute to modification of ground shaking, and thus, to seismic risk. In urban areas, these interactions are not limited to interactions between single buildings and the soil, but include interactions of an entire city and the soil. Since these interactions are not understood in detail as yet, they are not taken into account in the planning of urban areas and seismic risk assessment and mitigation. Until now, most studies of these effects have been carried out by numerical simulations without the possibility of a comparison between the predicted and the observed seismic wave fields. Only a very limited number of analyses tried to tackle the problem based on empirical data sets. The project USCINT aims at improving our understanding of interactions between buildings and the soil and among buildings through the soil during earthquake shaking by using both a unique empirical data set and numerical modeling. Better understanding of the interactions between buildings and the soil may contribute to the identification of areas of higher seismic risk and thus, to a better preparedness in case of an earthquake. Furthermore, this knowledge could be included in guidelines for standard risk assessment and mitigation approaches in urban areas. Finally, improving urban planning in the long term by taking soil-structure interaction and site-city interaction effects into account, can contribute to reduction of seismic risk.