A Template Matching Technique Based On Cross-correlation Harmonic Fitting Was Proposed To Detect The Upcoming Micro-Fluctuation Events

The microwave fluctuation impending earthquake is an abnormal event superimposed on the normal earth pulsation waveform due to the pre-slip and prerupture of the near earthquake source.However,the near earthquake microwave events mainly rely on artificial recognition,which is affected by subjective factors and inefficient.In this paper,the 2008 Wenchuan Ms8.0 earthquake and 2010 Yushu Ms7.1 earthquake are selected as the research examples,a template matching technique based on cross-correlation harmonic fitting was proposed to detect the upcoming microfluctuation events.The frequency spectrum curve of the template waveform and the event waveform to be matched in a wide frequency band within the epicenter distance of 150 km of the studied earthquake case is fitted with 9-order harmonic wave,and the correlation between the smoothing curve of the template spectrum and the smoothing curve of the event spectrum to be matched is calculated to match the template in the frequency domain.In this paper,the fitting order of the spectrum curve is discussed.Combined with the actual recognition results,the threshold selection of the crosscorrelation coefficient of the spectrum smooth curve in the three ranges of epicentral distance of 50 km,50km-100 km and 100km-150 km is studied respectively,and the selection results of the threshold are taken as the reference for the recognition of microwave fluctuation impending earthquake.Finally,the feasibility of template matching technology based on cross-correlation harmonic fitting in Microwave fluctuation impending earthquake identification is verified according to the recognition results.The results show that the template matching technology based on cross-correlation harmonious wave fitting greatly improves the efficiency of detecting microwave fluctuation impending strong earthquake,and reduce the workload of manual identification to one tenth of the original.The anomalies of microwave fluctuation impending strong earthquake of automatic recognition basically conforms to the tracking index based on Microwave fluctuation impending earthquake.This method gives full play to the advantages of cross-correlation calculation in spectrum analysis,solves the problems of artificial recognition affected by subjective factors and low efficiency,realizes the automatic recognition of impending earthquake microwave events,and provides scientific reference and judgment basis for short-term and impending earthquake prediction.