【摘要】 为探索地震的前兆,对一些较大地震前地脉动特征的变化作了简要的分析,发现1975年2月4日的海城7.3级地震前数天,近震中的地震台上(△≈20公里),脉动振幅异常减小;初步分析还表明,大震发生前,脉动方向以及脉动各分量相关系数的变化等现象也是值得引起注意的。更多还原

【Abstract】 In order to seek for the earthquake precursors, the characteristic variations of microseisms preceding several larger earthquake occurrences are analysed in brief. It is found that amplitude of microseism decreased abnormally at a station near the epicenter (Δ≈20km) about a few days before the occurrence of the Haicheng (海城) earthquake (M=7.3) on February 4, 1975. Preliminary analysis shows also that the phenomena such as the variation of the direction of approach of microseisms and the correlation between different components of the microseisms before large earthquakes are worthy of note.更多还原