古田地震水口水电站重力坝强震观测记录HHT分析

HHT Analyses on Observational Recordings of Strong Motion Recorded by Gravity Dam of Shuikou Hydropower Station in Gutian M_L4.6 Earthquake

利用HHT变换研究2008年3月6日福建古田ML4.6地震中,水口水电站重力坝强震反应台阵获取的强震反应观测资料的时频特性及重力坝结构动力特性,得到如下结论:(1)强震记录能量集中在0～15Hz频段和10～15s时段;(2)重力坝顺河向主频为3.7Hz。分析结果对认识水库地震近场地震动特性和重力坝地震反应有一定的实际意义。

Using Hilbert Huang Transform （ HHT）, we studied the timefrequency characteristic of observational data of strong motion recorded by the strong motion response arrays of the gravity dam in Shuikou Hydropower Sta tion in Gutian ML4. 6 earthquake and the structural dynamic characteristic of gravity dam. Conclusions were ob tained as follows： （ 1 ） The frequency of strong motion record energies was centralized between 0 and 15Hz while its time interval was centralized between 10s and 15s. （2） The dominant frequency along the stream di rection of concurrent gravity dam was 3.7Hz. The results have certain practical significance for the understanding of the ground motion characteristics in near field of reservoirs earthquake and the seismic response of gravity dam.