川滇分区地震烈度衰减特征研究

Study on Zonal Characteristics of Seismic Intensity Attenuation in Sichuan-Yunnan Region

考虑到不同区域地震烈度衰减规律的差异性，本文通过分析川滇地区地震空间分布、震害及烈度分布特征，搜集并整理了1900年以来川滇地区的140个5级以上地震案例，利用联合椭圆衰减模型，结合川滇地区的地质构造特征，建立了川滇分区地震烈度衰减关系。对比结果表明：不同区域的地震烈度衰减存在显著差异，尤其是在M=5和M=7级时区域差别明显：同时，与已有成果的对比结果也可看出，滇西地区在M=7级时近场烈度明显偏低，而川西北及滇中地区在M=5级时虽与中国西部地区基本一致，但也均低于其它分区。上述结果对川滇地区地震灾害快速评估和地震应急具有重要参考价值。

Considering the difference of seismic intensity attenuation law in different regions, in this paper we analyzed the spatial distribution of the earthquakes and caused damage and intensity characteristics in Sichuan-Yunnan region, collected and collated 140 cases of earthquakes with magnitude 5 and above since 1900. The seismic intensity attenuation is zoned according to the geological structure characteristics and fault type in the region. Then the zonal seismic intensity attenuation relationships are built up by using the united elliptic attenuation model. The results show that the significant differences of seismic intensity attenuation exist in different zones, especially at M=-5 and M=-7. Further comparison with previous study results, we found that the near field intensity with M=7 in the western Yunnan area is obviously lower than the previous results, while those in the northwest Sichuan and Yunnan region with M=-5 are consistent with one in the region of western China, but significantly lower than other regions. The results will provide an important reference in earthquake emergency or rapid disaster assessment.