Abstract: Reservoir earthquakes are different from natural earthquakes because of their shallower depth and heavier damage under small magnitude.Therefore,results of damage loss assessment,using traditional models,would be underestimated,the reason of which is that intensity attenuation models for moderate magnitude natural earthquakes could not generate fit intensity especially in near field.Though the research on new attenuation for reservoir induced earthquakes has been carried out for over decades of years in China,there are still not enough cases to support the analysis.To resolve the problem,a proposal in this paper is introduced to search useful materials from amounts of natural earthquakes. We adopt a kind of clustering means,set three classified indices of magnitude,depth and epicenter intensity,and then put all the earthquakes together for classification.After settling the optimal clustering number,some natural earthquakes which could be considered with similar damage to buildings as that in reservoir earthquakes.If we gather enough cases about both types of earthquakes, this method would provide much more materials to regress parameters of attenuation models.At last, this paper shows a set of intensity attenuation curves for reservoir earthquake.While compared with other attenuation models,the new ones are definitely giving a higher intensity and faster attenuation. According to the practical materials' accuracy,new attenuation models should be correct while the magnitude is below M_s6 and the scope of disaster is less than 50 kilometers.

Key words: reservoir earthquake, intensity, attenuation, earthquake case

摘要： 水库地震由于具有震源浅、震级小但破坏较同等级的天然地震重的特点,其地震烈度衰减关系在水库地震灾害预测中有着十分重要的研究意义。然而,由于水库地震事件数量少,历史震例往往缺乏地面烈度调查资料,这给研究工作带来了相当大的难度。为了解决资料不足的问题,文中采用聚类分析的方法,从丰富的天然地震中选择可与水库地震灾害类比的震例,把其烈度资料引入衰减模型进行回归分析,得到了新的地震烈度衰减关系;并与已有的研究成果和天然地震的烈度衰减进行比较,证明了这种方法具有合理性,所得到的水库地震烈度在近场普遍比天然地震烈度高,但由于加入了天然地震资料使得结果比已有水库地震烈度衰减慢且震中烈度稍低。

关键词: 水库地震, 烈度, 衰减模型, 震例