【摘要】 通过对１９８８～１９９６年首都圈４０个测点的地磁差值年变率δＦ变化的全面分析研究，获得了近期两次唐山震区中强地震的地磁差值年变率δＦ异常，是以磁报震探索和震磁关系研究较好的近场前兆震例。地磁差值年变率δＦ方法４年来已用于首都圈１年尺度地震趋势判断。更多还原

【Abstract】 This paper has abtained annual variation rate of anomaly of the geomagnetic difference before two Tangshan moderate strong earthquakes,according to whole analysis for its variation on 40 stations in the Capital Circle Area from 1988 to 1996.The analysis shows that it is a near field precursor example of earthquake with better seismomagnetic ralation.Its method is applied to annual judgement of earthquake trend for four years.更多还原