【摘要】 为了提取2013年10月至11月吉林省松原市M_S 5.0以上震群前后地磁异常变化信息,利用短时快速傅里叶变换方法,分析平均震中距为79 km的长春地磁台地磁场能量波动,发现该台Z分量在震前4个月于0.02 Hz频点能量出现异常波动,震前2个月达到峰值,随后逐渐平稳,恢复到正常水平期间发生地震。排除空间变化磁场影响和环境干扰,认为该异常变化与2013年松原M_S 5.0以上震群有关。更多还原

【Abstract】 In order to find geomagnetic abnormality associated with Songyuan earthquakes,the variance of geomagnetic energy of Changchun station,which is 79 km away from the epicenter,was calculated based on SFFT-trans form.The result showed that there was an obvious enhancement around 50 s of Z component about 4 months before earthquake and which reached to the maximum about 2 month before.The earthquake happened when it back to normal.We think the unusual enhancement of Z component related to Songyuan earthquake swarms.更多还原