磁暴与华北地区地震活动的关系

MAGNETIC STORM AND SEISMIC ACTIVITY IN NORTH CHINA

摘要:

利用了白家疃地磁台地磁月报和7日报中的K指数资料,将大于5的K指数全都折合成5的K指数。对磁暴扰动数N(K=5的个数)和华北地区1973~1992年的M_L≥5.0地震之间关系进行了统计分析,结果表明,磁暴具有大约10年左右的活跃-平静-活跃的周期变化。在半周期中,从上升年到高值年或从下降年到低值年中最大震级有同量级成对出现的特征;取月磁暴扰动数N≥40时为异常,异常后4个月内发生的地震占总地震数的68%,有震异常占总异常的61%;震级越大,异常越明显。分别对M_L≥5.0,M_L≥5.5,M_L≥6.0和M_L≥6.3(M_S6.0)的地震进行统计,有异常的地震占相应震级地震数各为61%、75%、89%和100%。.

Abstract:

Based on the monthly report and 7-day report of magnetic data of Baijiatan station,the K numbers of more than 5 are converted with a unit of K=5.Analysis on the magnetic number N(unit:K=5) and the earthquakes (M_L≥5.0) in North China from 1973 to 1992 indicates that the magnetic storm has a ten-years active-quiet-active period,the largest earthquakes occurred in pairs and in same grade during the semiperiod from the ascendant year to the highest year or from the declining year to the lowest year as well;the monthly magnetic disturbance number N higher than 40 is regarded as abnormality,earthquakes occurring during four months after the abnormality constitute 68 percent of the total earthquakes, and the abnormality associated with earthquakes constitutes 61 percent of total abnormality;this method has a better effect for those greater earthquakes,statistic analysis about the earthquakes of M_L≥5.0,M_L≥5.5,M_L≥6.0 and M_L≥6.3 indicates that the percentages of these earthquakes which had a abnormality are 61%,75%,89% and 100%,respectively.