天山造山带的宽频带地震台阵流动观测

Portable broadband seismic array observation of Tianshan orogenic belt

利用宽频带三分量数字地震台阵观测天然地震,可以获得岩石圈三维结构、物质组成和深部构造特征信息,从而提高对大陆岩石圈形成与演化的动力学过程和机制的认识,目前已成为地球科学领域的一个研究热点。由英国GURALP公司的三分量宽频带地震仪和美国REFTEK公司的数字地震记录系统构成宽频带三分量数字地震观测系统是当今国际上的流行配置,记录到的地震频率范围很大,可以同时记录体波和面波而不失真。利用这个宽频带三分量数字地震台阵的观测数据,对天山造山带远震剪切波分裂和岩石圈结构进行了研究,取得了良好的效果,这对揭示天山的隆升机制和盆-山耦合具有重要的意义。

By observing natural earthquakes using 3-component broadband digital seismic array, one can obtain the three dimensional structure, mass composition and tectonic characteristics in depth of lithosphere. This information is useful for improving the recognition of dynamic process and mechanism of continental lithospheric formation and evolution, which is a hot spot in geosciences field. Current mainstream seismic observation system consists of GURALP's 3-component broadband seismometer and REFTEK's digital seismic recording system. Such an observation system is able to record earthquake signals of wide range of frequencies. It can record simultaneously both body waves and surface waves without distortion. Using such a system, observations were carried out along the Chinese Tianshan Orogenic Belt at E86°-88°, and N41°-45° from September 2002 to September 2003. The about 500 km array, which consists of 28 stations with station spacing of 15–30 km, is generally perpendicular to the strike of the mountainous range. The observed data was used to study the shear wave splitting and lithospheric structure. This observations are of important significance in the study of the dynamic mechanism about the Tianshan uplift and mountain-basin coupling.