Site dependence of far-source ground motions during the Wenchuan earthquake
Longjun Xu1, Haiying Yu2, Wenhai Cao3, Lili Xie1
1 Research Center of Civil Engineering Disasters and Prevention, Harbin Institute of Technology at Weihai, Weihai 264209, China 2 Institute of Engineering Mechanics, China Earthquake Administration, Harbin 150080, China 3 Earthquake Administration of Weihai City, Weihai 264209, China
Site dependence of far-source ground motions during the Wenchuan earthquake
Longjun Xu1, Haiying Yu2, Wenhai Cao3, Lili Xie1
1 Research Center of Civil Engineering Disasters and Prevention, Harbin Institute of Technology at Weihai, Weihai 264209, China 2 Institute of Engineering Mechanics, China Earthquake Administration, Harbin 150080, China 3 Earthquake Administration of Weihai City, Weihai 264209, China
摘要This paper aimed to examine the site dependence and evaluate the methods for site analysis of far-source ground motions. This was achieved through the examination of frequency content estimated by different methods based on strong ground motions recorded at twelve far-source stations in Shandong province during the Wenchuan earthquake. The stations were located in sites with soil profiles ranging from code classes I to III. Approaches used included the Fourier amplitude spectrum (FAS), the earthquake response spectrum (ERS), the spectral ratio between the horizontal and the vertical components (H/V), the spectral ratio between the spectra at the site and at a reference site (SRRS), and coda wave analysis (CWA). Results showed that major periods of these ground motions obtained by FAS, ERS and H/V ratio methods were all evidently larger than site dominant periods; the periods were also different from each other and mainly reflected the frequency content of long period components. Prominent periods obtained by the SRRS approach neither illuminated the long period aspect nor efficiently determined site features of the motions. The CWA resulted in a period close to site period for stations with good quality recordings. The results obtained in this study will be useful for the evaluation of far-source effect in constructing seismic design spectra and in selecting methods for ground motion site analysis.
Abstract：This paper aimed to examine the site dependence and evaluate the methods for site analysis of far-source ground motions. This was achieved through the examination of frequency content estimated by different methods based on strong ground motions recorded at twelve far-source stations in Shandong province during the Wenchuan earthquake. The stations were located in sites with soil profiles ranging from code classes I to III. Approaches used included the Fourier amplitude spectrum (FAS), the earthquake response spectrum (ERS), the spectral ratio between the horizontal and the vertical components (H/V), the spectral ratio between the spectra at the site and at a reference site (SRRS), and coda wave analysis (CWA). Results showed that major periods of these ground motions obtained by FAS, ERS and H/V ratio methods were all evidently larger than site dominant periods; the periods were also different from each other and mainly reflected the frequency content of long period components. Prominent periods obtained by the SRRS approach neither illuminated the long period aspect nor efficiently determined site features of the motions. The CWA resulted in a period close to site period for stations with good quality recordings. The results obtained in this study will be useful for the evaluation of far-source effect in constructing seismic design spectra and in selecting methods for ground motion site analysis.
基金资助:National Natural Science Foundation of China (50808168), Ministry of Science and Technology of Weihai (2008087) and Foundation of Harbin Institute of Technology at Weihai (HIT(Y)200801)
通讯作者:
Longjun Xu
E-mail: xulongjun80@163.com
引用本文:
Longjun Xu, Haiying Yu, Wenhai Cao, Lili Xie. Site dependence of far-source ground motions during the Wenchuan earthquake[J]. 《地震学报》英文版, 2009, 22(5): 531-537.
Longjun Xu, Haiying Yu, Wenhai Cao, Lili Xie. Site dependence of far-source ground motions during the Wenchuan earthquake. Earthquake Science, 2009, 22(5): 531-537.
