2016年门源6.4级地震前连续重力频率特征分析

Frequency Characteristics of Continuous Gravity before the 2016 Menyuan M_S6.4 Earthquake

利用兰州地震台及高台地震台连续重力资料,分析研究了2016年1月21日门源地震前连续重力变化特征。对震前5 d及震后2 d秒采样数据使用快速傅里叶变换(FFT)变换方法进行功率谱分析,发现其频率幅度持续增大,临震前一天减小到正常值后发生地震,同时对震前6 d秒采样数据进行滤波处理,发现在临震前48 h观测到重力扰动信号,周期为4～8 s。门源地震前观测到的频率特征及重力扰动信号分析,可能反映了门源地震前孕震的一个整体过程,这为揭示门源地震产生机理提供了参考。

Based on continuous gravity data at the Lanzhou and Gaotai seismic stations,variations in continuous gravity prior to the Menyuan earthquake that occurred on January 21,2016 were analyzed.Fast Fourier transform was used to conduct a power spectral analysis on data sampled five days before and two days after the earthquake.The results showed that the frequency amplitude continuously increased,then decreased to a normal value within one day of the earthquake. Furthermore,data from the second sampling,i.e.,data sampled 6 days before the earthquake,was filtered,and we found that the gravity disturbance signal was observed within the 48-h preceding the earthquake,with a period of 4-8 s.The frequency characteristics and gravity disturbance signal observed prior to the Menyuan earthquake may reflect a whole seismogenic process before the earthquake,providing a reference for revealing the mechanism of the Menyuan earthquake.