Study Of The Variationcharacteristicsand Earthquake Prediction Of The Geoelectric Field With Dominant Azimuth

Our country is the only one in the world that conducts large-scale geoelectric field observations.The traditional view is that the abnormal geoelectric field before the earthquake is mainly the electromagnetic signal produced by rock squeezing and fracture.Recent studies have shown that the diurnal wave of the geoelectric field is caused by the geoelectric field,and on this basis,the tidal mechanism theory of the geoelectric field change is gradually formed.And then establish the dominant azimuth model of the geoelectric field.Based on the tidal mechanism theory of the geodetic electric field and the seepage(movement)model of the water(charge)in the rock mass fissures,it is believed that the geodetic electric field of each site has a corresponding dominant position.This study shows that the dominant azimuth of the geodetic electric field at different sites has a corresponding range of normal variation.Based on more than 300 cases of moderately strong earthquakes in the three major regions of the Chinese mainland(the northeast,northwest,and north-south seismic belts)in the past ten years,the system calculated the data before and after these earthquakes by applying minute-value observation data from surrounding geoelectric stations for several years.The dominant azimuth of the geoelectric field and its change process,and the characteristics of abnormal changes in the dominant azimuth of the geoelectric field are obtained.At the same time,combined with rock physics,the mechanism of the normal and abnormal changes of the dominant azimuth angle of the geoelectric field is discussed.It is preliminarily believed that the complex stress loading and unloading process caused the fracture structure of the underground rock mass of the site to change during the earthquake incubation process.As a result,the dominant azimuth of the geoelectric field changes abnormally.Finally,based on statistical methods,anomaly detection was performed on the abnormal data of the typical electric field dominant azimuth,and anomaly warning was initially realized.This research provides a foundation for the application of geoelectric field superior azimuth method in earthquake prediction,and also provides a new idea for exploring the relationship between geoelectric field and earthquake,and has certain significance for using geoelectric field observations for earthquake prediction.