【摘要】 利用磁通门观测数据进行分析,结果表明与周期在几分钟到几小时的极化值一样,5~100 s的磁场极化值Yzh同样具有年变化规律,因此简单的依据极化值Yzh由低值向高值的变化判断是否存在震前电磁辐射异常存在很大的风险。为此,分析了采用富氏拟合技术消除半年以上变化周期的Yzh与台站周边地区地震的关系,表明极化值Yzh高值与其后2个月内台站周边地区地震有很好的对应关系,且大部分地震都发生在1个月内。分析还表明Yzh高值异常持续时间一般为3~5 d,与外空磁场剧烈活动没有关系;单纯采用夜间观测数据不及采用全天观测数据的效果。更多还原

【Abstract】 This paper did analysis by using the data of fluxgate magnetometer.The result showed that the ratio of the spectral intensities of the vertical to horizontal components of the magnetic field(polarization) of which periods were from 5 to 100 s,same as the polarization of which periods were from several minutes to several hours,also had the annual variation,there would be risk failure when judging whether there were ULF magnetic field anomalies prior to earthquakes only by the variation of the polarization from low value to high value.So the paper applied the fitting of Fourier to remove the relationship between the polarization Yzh of which periods greater than half year and the earthquakes surrounding observation station,and result showed that the high value of the polarization Yzh had a close relationship with the earthquakes which happened in two months after the high value appeared,and most of these earthquakes happened in one month.It was also showed that the duration of precursory of high value was about from one day to five days,and no significant correlation with the geomagnetic activity was found,and there was no advantage using the data at night than that in all day.更多还原