利用中级地震激发的自由振荡简振模研究我国大陆中部地区上地幔介质横向特性  

Research on Lateral Features of Upper Mantle Medium in Chinese Central Mainland with Earth's Free Oscillation Normal Modes Excited by Moderate Earthquakes

作　　者：王建国 胡小刚 柳林涛 

机构地区：[1]大地测量与地球动力学国家重点实验室,武汉市徐东大街340号430077 [2]中国科学院大学地球科学学院,北京市玉泉路19号甲100049

出　　处：《大地测量与地球动力学》2018年第2期161-166,共6页Journal of Geodesy and Geodynamics

基　　金：国家重大科学仪器设备开发专项(2011YQ120045);国家自然科学基金(41174022;41374029;41674100)~~

摘　　要：选取2004~2015年发生在我国大陆附近的14个中级地震(6.5<M_W<7.5),利用安装有STS-1宽频带地震仪的恩施、昆明和西安台记录值以及丽江和武汉台的超导重力仪数据,分别获取球型简振模观测值。根据地震事件的震源机制解和横向均匀地球模型,计算各台站的球型简振模模拟值。比较观测值和模拟值在振幅和频率上的差异,分析我国大陆台站覆盖区域地下结构横向特性。结果显示,所选地震激发的简振模观测值和模拟值振幅在3.0~6.0mHz的频率范围内拟合较好,表明我国大陆中部地区尤其是所选台站附近上地幔200~660km以下没有大范围的横向不均匀结构。This paper selects 14 moderate earthquake （6.5〈Mw〈7.5） events near mainland of China occurred during 2004 to 2015. Analyzing records from Enshi, Kunming and Xi＇an stations which are equipped with STS-1 broadband seismographs and records from Lijiang and Wuhan stations which are equipped with superconducting gravimeters, we can obtain observed spheroidal modes. According to the focal mechanism solution of seismic events and lateral homogeneous earth model, we calculate the synthetic values of spherical modes of each station. Then we compare discrepancy in the amplitudes and frequencies between observations and synthetic values to analyze lateral features of underground structure of areas covered by Chinese mainland stations. Results show that the observed amplitudes a- gree well with synthetic modes at 3.0~6.0 mHz, it＇s a clear evidence that there is not large scale lat- eral inhomogeneous structure in the upper mantle below 200~660 km especially in those areas around selected stations in Chinese central mainland.

关 键 词：中级地震 球型简振模 宽频带地震仪 超导重力仪 横向不均匀 

分 类 号：P315[天文地球—地震学]