摘要
为更好地开展地磁异常变化与地震的关系,通过对河北及周边地区2017—2021年流动地磁矢量资料,采用模值量化的计算方法,研究发生在测区范围内震级M_(L)≥4.0地震震中位置变化模值的分布特征。结果表明:H模和F模的图像分布形态极为相似。测区主要异常形态与测区地质构造对岩石圈磁场变化的控制作用不强。测区岩石圈磁场时间变化总体稳定,局部地区存在起伏波动变化。80%的震例均发生在H模和F模的低值区,且震中模值与模值测区均值的比值ρ的取值集中在0.2~0.9区间范围内,M_(L)和ρ不具备线性相关性。将标准模作为研究地区模值异常的参考阈值,得到H模和F模的参考异常阈值分别为3.10和3.54。采用改进的R值评估方法,得到基于模值测区均值的R为0.3。可见,基于模值异常的地震预测水平还很低,流动地磁的异常研判工作仍处于探索阶段。
In order to better investigate the relationship between geomagnetic anomaly changes and earthquakes,the distribution characteristics of the change modulus of epicenter position of earthquakes with M_(L)≥4.0 within the measurement area were studied by using modular quantification calculation method based on the mobile geomagnetic vector data of Hebei and surrounding areas from 2017 to 2021.The results show that the image distribution morphology of H-mode and F-mode is very similar.The main abnormal forms and geological structures in the survey area have a weak control over the changes in the lithospheric magnetic field.The temporal variation of the lithospheric magnetic field in the survey area is generally stable,with fluctuations in some areas 80%of the earthquake cases occur in the low value areas of the H-mode and F-mode,and the values of the ratio(the ratio of the epicenter modulus to the mean value of the modulus measurement area)are concentrated in the range of 0.2 to 0.9.There is no linear correlation between the earthquake magnitude and the ratio.Using the standard mode as the reference threshold for local mode value anomalies,the reference anomaly thresholds for H-mode and F-mode are obtained to be 3.10 and 3.54,respectively.Using an improved R-value evaluation method,a R-value of 0.3 is obtained based on the mean of the modulus measurement area.It is concluded that the level of earthquake prediction based on modulus anomalies is still very low,and the research and judgment of mobile geomagnetic anomalies is still in the exploratory stage.
作者
赵慧琴
李博
毛丰龙
ZHAO Hui-qin;LI Bo;MAO Feng-long(Hebei Hongshan National Observatory on Thick Sediments and Seismic Hazards,Xingtai 054000,China;Hebei Province Baoding Earthquake Monitoring Center Station,Baoding 071000,China)
出处
《科学技术与工程》
北大核心
2024年第13期5271-5277,共7页
Science Technology and Engineering
基金
河北省地震科技星火计划(DZ2023120800024,DZ2021121500001,DZ2024112200007)。
关键词
流动地磁
岩石圈磁场
低模值
模值异常
模值测区均值
mobile geomagnetism
lithosphere magnetic field
low modulus value
abnormal modulus
mean value of modulus measurement area
