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利用固定半径法和直接计算法系统研究了华北地区（Ｎ３０°～４３°，λＥ１０６°～１２５°）１３个Ｋ表性子区地震时间结构的广义维数Ｄｑ—ｑ及标度指数谱ｆ（ａ）—ａ的特征，并与单—Ｄｑ—ｔ曲线进行了对比。结果表明；（１）华北地区地震时间结构为多分形结构，单一分形不能完整地描述其分形特征，应该用Ｄｑ—ｑ或ｆ（ａ）—ａ来加以分析；（２）华北强震前的０．５～２．０年．周围地区地震活动的时间多分形结构出现异常，主要表现为ｑ为负时Ｄｑ增大、ｑ为正时Ｄｑ减小，或ｆ（ａ）两端点下降，ａ跨度增大及顶点右偏等现象，这是对地震密集—平静现象的另一种描述；（３）华北地区地震时间多分形方法回顾性预报评分Ｒ＝０．４７，说明其有一定预报效能，是有前景的预报方法。
The generalized dimension Dq-q and scale index spectrum f (a) of the seismic time structure of 13 K-shaped sub-regions in North China (N30 ° ~ 43 °, λE106 ° ~125 °) are systematically studied by the fixed radius method and the direct calculation method ) -a, and compared with the single-Dq-t curve. The results show that: (1) the time structure of the earthquake in North China is multifractal structure, the single fractal can not describe its fractal features completely and should be analyzed by Dq-q or f (a) -a; (2) 0. 5 ~ 2. 0 years. The multi-fractal structure of seismic activity in the surrounding area is abnormal. The main features are as follows: Dq increases when q is negative, Dq decreases when q is positive, or decreases both ends of f (a) , Which is another description of the phenomenon of seismic intensity-calmness; (3) The retrospective forecast score of the multi-fractal method for seismic time in North China R = 0.47, indicating that it has some forecasting effectiveness and is a promising forecasting method.