基于岩石圈磁场年变对河北及邻区中小震震磁特征的分析

打开文本图片集

中图分类号：P318 文献标志码：A 文章编号：1000-0844（2025）05—1201—11

Abstract： Mobile geomagnetic vector data from 2O16 to 2O21 and Ms⩾3.0 earthquakes from 2017 to 2022 are used to quantify and statistically analyze the seismomagnetic characteristics of moderate small earthquakes in Hebei and adjacent areas based on annual variations of the lithospheric magnetic field.Based on the results，epicenters are predominantly distributed near zero-variation lines of magnetic declination （D） ，inclination （I） ，and total intensity （F ）with 75.0% ， 50.0% ，and （204号 46.4% of earthquakes located ⩽50km from D ， I ，and F zero-variation lines，respectively. This is the most significant correlation for magnetic declination. Statistical analysis of three-component variations reveals that the maximum amplitudes of D，I ，and F at the epicenters are 1.37′ ， 0.69′ ，and 8.52nT ，respectively. Specifically， 60.7% of epicenters exhibit a D variation within ±0.40′ ， 60.7% show an I variation within ±0.25′ ，and 75.0% display an F variation within ±3.50nT . No epicenters coincide with the extremum zones of these components. The values of the vector modulus and horizontal vector modulus at epicenters are broadly distributed， while a relatively high proportion of epicenters correspond to smaller values. Finally， scatter plots of the magnitude versus lithospheric magnetic field variations at epicenters and the subsequent calculation of correlation coeficients demonstrate no significant correlation between the earthquake magnitude and these parameters.

Keywords： mobile geomagnetic survey；annual variation of lithospheric magnetic field;moderate small earthquakes; seismomagnetic anomaly

0 引言

地震的孕育、发生是一个极其复杂的过程，由于影响因素很多，伴随这一过程产生的异常现象也就更加复杂。（剩余17427字）