Discrimination of Probability Distribution and Low Frequency Anomaly of Seismic Wave Data

In order to find the distribution characteristics of low frequency signals and probability density before the Alashan M5.8 earthquake on April 15, 2015 in Inner Mongolia, the waveform data of three stations (from 00 points on April 1, 2015 to 23 points on April 15, 2015) were analyzed by using the continuous digital seismic waveform data of Wuhai, Shizuishan and Dongshengmiao stations. At the same time, the frequency and probability density distributions of the spectrum anomaly period are also tracked. The results show that: (1) The probability density distributions of seismic waveforms recorded by the three stations with and without seismic time periods are completely different, and the distribution of probability density with time change has the character of generalized Gaussian distribution. (2) Before the Azuoqi M5.8 Earthquake, the seismic waveforms recorded at Wuhai, Shizuishan and Dongshengmiao seismic stations near the epicenter not only exhibited the phenomenon of frequency shift to low frequency, but also changed the distribution of frequency and probability density in the corresponding period of abnormal occurrence. However, in the same period, the change patterns of the three stations were similar, and the probability density was divided into two parts. The distribution of probability density varies greatly in different time periods.