宁洱6．4级地震强震动观测记录异常场地影响分析

“十五”期间建设并投入试运行的中国数字强震动台网云南区域台网有20多个强震动台站记录到宁洱6．4级地震产生的地面运动。但值得注意的是，位于实地考察得到的Ⅵ度以上烈度区内或者其附近的4个强震台站，从加速度峰值、速度峰值与烈度的对应关系来看，与实际震害现象反映出的烈度有一定差异。究其原因，地震动幅值的大小和震级的大小有着直接的关系，但同时也和地震波的传播途径及场地条件等因素有关。因此，从场地因素的角度出发，从覆盖土层、地形地貌和地质构造条件等方面对造成强震动记录值偏大的原因进行了调查分析。在此基础上，对今后云南地区地震动研究场地影响的考虑提出了一些思路和建议。

SITE EFFECT ANALYSIS ON STRONG MOTION OBSERVATION ANOMALIES OF NING'ER EARTHQUAKE WITH Ms6.4

There are more than twenty strong motion stations in Yunnan regional network （China Digital Strong Motion Network） recorded ground motion of Ning＇er earthquake with Ms6.4 which were built during ＂Tenth five plan＂. According to corresponding relationship between peak acceleration.peak velocity and intensity ,intensive region of VI degree and＇nearby stations are quite different from real earthquake disaster phenomena. The amplitude of ground motion is closely related to magnitude but also affected by transmission route and site condition. They analyzed causes of strong mo tion records oversized through overlying soil. topography and geomorphology and tectonic structure condition. They also provide suggestion for future site effect of ground motion research in Yunnan.