Analysis of Spectral Shift Characteristics of Foreshocks before Strong Earthquakes in Xinjiang Region
Using the method of spectral shift for foreshock or generalized foreshock identification,this study focuses on the fore-shocks of moderate to strong earthquakes(MS≥5.0)that occurred in the Xinjiang Uygur Autonomous Region from January 2013 to November 2022.By analyzing their frequency spectra,the spectral characteristics of foreshocks in the Xinjiang region are examined.The results show that spectral shifts occur in up to 70%of the foreshocks of moderate earthquakes,indicating that the spectral shift method has certain significance for short-term earthquake prediction in this region.The critical value for spectral shift towards the lower end is 1.5 Hz.In direct foreshocks,the probability of spectral shifts in earthquakes with MS≥3.5 reaches 85%,while it is lower for earthquakes with MS<3.5.Earthquakes with meaningful foreshocks show a clear positive correlation between the rate of spectral shift and the intensity of subsequent moderate to strong earthquakes when MS≥5.2.However,due to the small amount of data,this positive correlation is considered to have low reliability and requires further research.
moderate to strong earthquakesforeshocksspectral shift method
万方数据
维普
