Application of abnormal changes in the lithospheric magnetic field in the northern section of the North-South Seismic Belt from 2020 to 2021 in earthquake prediction and forecasting
Severe changes in the local lithosphere,such as volcanic eruptions and earthquakes,can cause rapid changes in the regional lithospheric magnetic field.Geomagnetic scholars generally study the seismic magnetic relationship by monitoring changes in the regional magnetic field and selecting reasonable mathematical models.This article is based on the mobile geomagnetic observation data of the northern segment of the north-south seismic belt from 2020 to 2021.Through daily variation normalization correction,long-term variation correction,and stripping of the lithospheric magnetic field,the spatiotemporal distribution characteristics of the regional lithospheric magnetic field and the abnormal changes of magnetic elements at the locations of 7 moderately strong earthquakes are analyzed and studied.The results show that the horizontal vector of the lithospheric magnetic field in the study area forms several weak variation regions,The 7 moderately strong earthquakes discussed in this article all occurred within or at the edge of the weak variation zone of the horizontal vector of the lithospheric magnetic field,and there was a trend of turning,diverging,hedging,or magnitude mutation in the horizontal vector at the location of the earthquake;There is also a correlation between the annual variation contour lines of various elements of the lithospheric magnetic field and the location of earthquakes,as shown in the following:the"0"value line of the ΔD、ΔY、ΔZ、ΔF、ΔI、ΔX contour line shows a clear positional feature with moderate strong earthquakes,that is,the earthquake location is close to the"0"value line,and only from the distance between the earthquake location and the"0"value line,ΔD、ΔY、ΔZ is better ΔF、ΔI、ΔX,than three elements.This obvious change in seismic and magnetic characteristics has strong directionality in predicting the location of moderate to strong earthquakes;In addition,except for the Mangya earthquake with a magnitude of 5.5,all other earthquakes are relatively close to the anomaly areas designated based on the anomalies of the lithospheric magnetic field elements.Among them,the Menyuan earthquake with a magnitude of 6.9,the Malkang earthquake with a magnitude of 5.8/6.0,and the Zaduo earthquake with a magnitude of 5.9 are located within 30 km from the nearest abnormal change area of the lithospheric magnetic field,and the seismic effect is good.
Annual variation of the lithospheric magnetic fieldModerately strong earthquakesWeak changes"0"value line
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