Characteristics of S-wave Envelope Broadening in the Changbaishan Tianchi Volcano

作     者：Fan Xiaoping Li Qinghe He Haibing Yang Congjie Jin Shumei 

作者机构：Earthquake Administration of Jiangsu Province Nanjing 210014 China Earthquake Administration of Zhenjiang City Zhenjiang 212001 China 

出 版 物：《Earthquake Research in China》 (中国地震研究（英文版）)

年 卷 期：2010年第24卷第3期

页      面：385-393页

学科分类：070801[理学-固体地球物理学] 07[理学] 0708[理学-地球物理学] 

基　　金：sponsored by the National Key Technology R&D Program (2006BAC01B04) the Joint Earthquake Science Foundation (A08026,A07138),China 

主　　题：Changbaishan Tianchi volcano S-wave envelope broadening Peak delay timeof S-waves 

摘      要：High-frequency S-wave seismogram envelopes of microearthquakes broaden with increasing travel distance,a phenomenon known as S-wave envelope broadening. Multiple forward scattering and diffraction for the random inhomogeneities along the seismic ray path are the main causes of S-wave envelope broadening,so the phenomenon of S-wave envelope broadening is used to study the inhomogeneity of the medium. The peak delay time of an S-wave,which is defined as the time lag from the direct S-wave onset to the maximum amplitude arrival of its envelope,is accepted to quantify S-wave envelope broadening. 204 small earthquake records in Changbaishan Tianchi volcano were analyzed by the S-wave envelope broadening algorithm. The results show that S-wave envelope broadening in the Changbaishan Tianchi volcano is obvious,and that the peak delay time of S-wave has a positive correlation with the hypocenter distance and frequency of the S-wave. The relationships between the S-wave peak delay time and the hypocenter distance for different frequency bands were obtained using the statistics method. The results are beneficial to the understanding of the S-wave envelope broadening phenomena and the quantitative research on the inhomogeneities of the crust medium in the Changbaishan Tianchi volcano region.