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利用华北地震台阵垂直分量的观测资料,采用滑动绝对平均方法对资料进行预处理,通过互相关方法从背景噪声中提取瑞利面波的格林函数,开发了群速度频散曲线的自动提取工具,测量了位于华北盆地、燕山隆起和太行山隆起的3条频散曲线,反演得到了3个区域的S波速度结构.研究分析表明,滑动绝对平均方法可以有效降低地震和台站附近干扰源的影响.为了得到可靠的层析成像结果,应计算格林函数的信噪比,选择高信噪比的格林函数测量其频散曲线,进行层析成像反演.当信噪比大于7时,一般都能得到稳定可靠的频散曲线.群速度频散曲线的最大可信周期(Tmax)与台站间距有关,华北地区最大可信周期以不超过台站间距的1/12为宜,周期大于Tmax时不同月份测得的频散曲线变化较大.
Based on the observation data of the vertical component of North China Seismic Array, the data are preprocessed by the sliding average method. The Green’s function of Rayleigh surface wave is extracted from the background noise by cross-correlation method. An automatic extraction tool of group velocity dispersion curve is developed , Three dispersion curves measured in the North China Basin, the Yanshan uplift and the Taihang uplift have been measured and the S-wave velocity structures of the three regions have been obtained by inversion.The analysis and analysis show that the sliding absolute averaging method can effectively reduce the seismic and station interference In order to obtain a reliable tomographic imaging results, the signal to noise ratio of Green’s function should be calculated and Green’s function with high signal-to-noise ratio should be chosen to measure its dispersion curve for tomographic inversion.When signal to noise ratio is more than 7, Generally, a stable and reliable dispersion curve can be obtained.The maximum credible period (Tmax) of the group velocity dispersion curve is related to the station spacing, and the maximum credible cycle in North China is less than 1/12 of the station spacing, The dispersion curve measured in different months is larger than Tmax.