Research On Anomaly Analysis Method Of Magnetic Declination Data For Large Earthquakes

Among the geomagnetic elements,the declination is less affected by magnetic storms and more affected by earthquakes.Therefore,this article is used the second data of the geomagnetic declination recorded by the National Geomagnetic Network of earthquakes with magnitude 7 as the research object to establish a geomagnetic declination observation model,to study the key elements used to extract geomagnetic anomaly information: geomagnetic declination limit anomaly value and anomaly degree.So as to provide a new method for the study of large earthquake prediction.This article is combined the characteristics of large earthquake geomagnetic declination data observation,non-seismic anomaly data,namely the distribution and distribution characteristics of missing numbers;in earthquake prediction and prediction,the problem of missing numbers of geomagnetic data is more common,in order to ensure the continuity of the geomagnetic sequence and easy extraction After analyzing geomagnetic information and studying various interpolation algorithms,different interpolation algorithms are designed for different missing numbers;the autoregressive moving average ARMA prediction model is used for geomagnetic non-seismic data interpolation processing,and interpolation experiments and mean interpolation are designed,Comparative analysis of the interpolation effect of linear interpolation.Because geomagnetic data is non-stationary data,this paper uses first-order difference to eliminate random interference before data processing,and second-order difference to make non-stationary data stable.This paper is considered that the duration and spatial extent of geomagnetic anomalies have a certain relationship with the magnitude of the magnitude,and thus establishes the limit anomaly value and anomaly degree analysis model of the geomagnetic declination angle of large earthquakes.The improved differential autoregressive moving average autoregressive model(ARIMA)is mainly used to predict the geomagnetic declination D,and the anomaly recognition algorithm is constructed with the actual observation value;considering that the data characteristics of each station may be different,in order to reduce the geomagnetic interference,the exploration is suitable for Anomaly discrimination interval with reasonable geomagnetic declination.This paper uses the combination of actual observations and predicted values to limit the abnormal value and the degree of anomaly,and uses the continuous threshold method to comprehensively determine the geomagnetic declination anomaly of major earthquakes.This paper is mainly used the geomagnetic declination second data of 70 geomagnetic stations recorded by the National Geomagnetic Network Center since the Wenchuan earthquake in five major earthquakes with a magnitude of 7.0 or more as the research object,and extracts the geomagnetic declination limit anomaly value and the degree of geomagnetic declination anomaly.It is found that the higher the magnitude of a major earthquake,the more the occurrence of abnormal time periods,the longer the duration of the geomagnetic limit anomaly,the longer the duration of the anomaly degree,and the greater the value of the anomaly degree.The geomagnetic declination anomaly analysis method used in this paper combines the limit anomaly value,the anomaly degree and the continuous threshold method,and uses all geomagnetic stations to analyze the geomagnetic anomaly,which overcomes the shortcomings of a single analysis method and makes it easier to find the abnormality of the geomagnetic declination.Improve the reliability of analyzing geomagnetic anomalies.Subsequent seismic data components can be added,and the method can be further applied to the horizontal component H,the vertical component Z,and the total field intensity F.It is expected to provide a new method for the prediction of large earthquakes.