张家口地震台和兴隆地震台地脉动信号初步分析

选取河北省张家口和兴隆2个台站的数字化地震仪连续1年,每日02～03时的地脉动记录,计算功率谱和自相关函数。结果发现兴隆台脉动谱中有4个比较突出的峰值,分别为0．3Hz、3Hz、8Hz、15Hz,张家口台只有3个峰值0．3Hz、3Hz、15Hz。兴隆台UD向的自相关函数呈现出一种比较典型的“红噪声”形态,EW向则呈现出负相关特征,认为可能是只作用于水平向的倾斜脉动的影响。小幅度的仪器干扰信号无论从脉冲标定还是地震波形中都很难发现的,而对脉动进行谱分析则很容易分辨。兴隆台和张家口台地脉动卓越周期时间曲线,基本集中在0．3秒,比较稳定。

Preliminary analysis to the signals of ground microtremor in Zhangjiakou and Xinglong Seismostation

The power spectra and autocorrelation function of the ground microtremor records in Zhangjiakou and Xinglong Seismostation are calculated. The results show that there are 4 peak values in the microtremor spectra of Xinglong Seismostation (0.3Hz, 3Hz, 8Hz,15Hz) and 3 peak values in Zhangjiakou Seismostation (0.3Hz, 3Hz, and 15Hz). The autocorrelation function in the UD direction of Xinglong station showed a typical "red noise" shape, but its EW direction showed negative correlation, which may be the affection of slantwise pulsation that acts on only in horizontal direction. Small instrumental interference signal is hard to distinguish, whether is from pulse calibration or seismic waves, but it is easy in spectral analysis of ground microtremor. The predominant cycle of ground microtremor in the two stations, which concentrated basically in 0.3s, was relatively stable.