历史大震烈度推算新方法研究

Study on the New Method for Estimating the Intensity of Historical Large Earthquakes

历史大地震的烈度对烈度区划编制、建筑设防、城市规划、震灾情景模拟和历史灾害研究等具有重要的参考作用。该文提出了一种利用地震烈度衰减模型和余震数据推断历史大地震烈度的新方法。以1668年郯城8 1/2级地震为例讨论了不同模型和数据组合的效果,并使用1556年陕西华县8 1/4级地震和2008年汶川8.0级地震进行了验证。结果显示:最短断层距模型和主震、强余震数据组合计算的结果最佳;计算的烈度值接近权威机构发布的烈度值,能较准确反映烈度的分布范围;该方法考虑了场地的影响,计算结果可以展示区域内烈度分布差异。在综合考虑史料和地质调查资料的基础上,可以用于校正精度差的历史大地震等震线,为区域地震灾害防御提供科学依据。

The intensity of historical large earthquakes is an important reference for intensity zoning preparation,building design,urban planning,earthquake scenario simulation and historical disaster research.In this paper,a new method for inferring intensity of historical earthquakes is proposed by combining the seismic intensity attenuation model with aftershock data.The effects of different model and data combinations are discussed using the Tancheng M 8 1/2 earthquake in 1668 as an example and validated using two examples of earthquakes,the Huaxian M 8 1/4 earthquake in Shaanxi in 1556 and the Wenchuan M 8.0 earthquake in 2008.The results of the study show that the combination of the shortest fault distance model and the data of main shock and strong aftershock is the best.The intensity calculated by the method is close to the intensity values issued by authoritative agencies and can reflect the distribution range of intensity accurately;This method takes into account the influence of site,and the results can show the differences in intensity distribution within the region.Based on the comprehensive consideration of historical data and geological survey data,it can be used to correct the isochrones of historical large earthquakes with poor accuracy and provide a scientific basis for regional earthquake disaster defense.