2012年彝良Ms5.7、Ms5.6地震场地地震动反应

2012年9月7日云南昭通彝良发生了M_s5.和、M_s5.6级两次地震，此次地震引发了极其严重的滑坡和崩塌等地震地质灾害，同时地震波放大效应还引起高烈度异常区。利用彝良地震烈度圈内6个台站记录到的主震加速度时程，通过截取S波窗，采用标准谱比法和水平垂直谱比法研究其场地地震动反应。结果表明:两种方法能给出较为一致的谱比曲线和卓越频率，但场地反应数值差异较大，标准谱比法的结果受到参考台站自身场地反应的影响；靖安台的软弱土层对地震动的放大作用较为显著，是造成烈度异常的主要原因。

Site effects research on Yiliang Ms5.7 and Ms5.6 earthquake in 2012

Two earthquakes of M_s5.7 and M_s5.6 struck the Yiliang, Zhaotong, on September 7, 2012. Serious geological disaster like landslide, collapse were triggered and the high intensity anomaly area was caused by the amplification effect. By truncating the S wave window form major earthquake acceleration time history recorded by 6 stations in Yiliang, the site effect was researched through standard spectral ratio method and horizontal-vertical spectral ratio method. The results shows that:the two methods can provide consistent spectral ratio curve and predominant frequency. However, the site effects differ largely. The results of standard spectral ratio method are affected by the site effects of the reference station. The site amplification effects of soft soil at Jingan station are obvious, which mainly causes the intensity anomaly.