【摘要】 基于大震前前兆起伏加剧具有普适性的特征，本文研究了１９９０年共和Ｍｓ７．０地震前地震频次、小震调制比、地下水中氧含量及泉水流量等异常起伏加剧的多层次性。结果表明，各台大多数前兆异常可分出３个层次。综合分析各台前兆异常的起伏加剧现象，可以发现，该次地震前异常群体的演变过程可分为４个层次，本文结合孕震过程对４个层次进行了分析。根据大震前兆起伏加剧的多层次性可以对大震进行跟踪预报。更多还原

【Abstract】 Based on the universal law of precursory fluctuation intensification before strong earth-quakes,this paper takes the l990 Gonghe strong earthquake as an example to study multi-hi-erarchy of the precursory fluctuation intensification of the small earthquake frequency,themodulation ratio of small earthquakes,radon in groundwater and hydraulic discharge in springbefore the earthquake. According to the phenomenon authors considered that the multi-hierar-chy of the precursory fluctuation intensification is an important path for prediction by followingthe tracks of a strong earthquake.更多还原