Abstract: Lushan M7.0 earthquake on April 20, 2013 occurred on the southern segment of Longmen Shan Fault zone. It is another strong earthquake after the Wenchuan M8.0 earthquake, rather than an aftershock. A total of 196 people died in Lushan M7.0 earthquake, 21 people missing, and 13019 injured. In this paper, we use the April 20, 2013 Lushan M7.0 earthquake strong motion records to calculate equivalent peak acceleration A_0.5 and convert it into the instrumental intensity. Then, we carry out the comparative analysis of instrumental intensity and surveyed intensity at the spots in the range of 5 kilometers around the stations. The results show a coincidence degree of 58.6% between the instrumental intensity and surveyed intensity, with the deviation less than ±1 degree. Meanwhile, we also recognize that there is a big dispersion of the observed ground motion parameters, even in the same macro-intensity. It is uncertain about the corresponding relationship between the individual station measured ground motion parameter values and the seismic intensity. The damage may be caused by earthquake ground motion characteristics, building types and site conditions and other factors, and therefore the difference between instrument intensity and actual seismic intensity cannot be ignored. On the whole, instrumental seismic intensity has potential for determining the range of seismic intensity, thus to provide quantitative reference, especially, in the absence of earthquake site investigation initially.

Key words: Lushan M7.0 earthquake, seismic intensity, instrumental intensity, survey spot intensity

摘要： 2013年4月20日四川芦山7.0级地震发生在龙门山断裂带南段，该地震是继汶川8.0级地震后的1次强震，但并非余震。文中利用2013年4月20日芦山地震的强震记录计算等效峰值加速度A_0.5换算地震仪器烈度，并且将地震仪器烈度与强震台站周边5km内调查点烈度对比分析。结果表明，芦山地震的仪器烈度与周边调查点烈度吻合度58.6%，且偏差不超过1度。然而，即使宏观烈度相同，观测地面运动参数也存在较大离散度。但在缺少现场调查的震后初期，地震仪器烈度有可能为地震烈度范围判断提供定量的参考指标。

关键词: 芦山地震, 地震烈度, 仪器烈度, 调查点烈度