摘要
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 characteristics of generalized dimension Dq-q and scale index spectrum f(a) -a of time structure of earthquakes in 13 typical subareas in North China (N30°- 40°, λE106°～125°) were systematicaly studied with fixed radius method and directe calculation method. It is compared with single curve Dq-q and the result shows: (1) The time structure of earthquakes in North China is a multi-fractal structure. Single fracter can not completly describe its fractal characteristics,so it should be analysed with Dq-q or f(a) -a; (2) Multi-fractal structure anomaly of time appears 0. 5～2. 0 years before strong earthquakes happened in North China. The anomalies mainly are: Dq increaseas when q is negative;Dq decreases or the two ends of f(a) descend,the span of increases and the vertex moves right when q is positive. This is another description for the phenomenon of dense and quiescence of earthquakes. (3) The multi-f racial method for time structure of earthquakes in North China has certain effect on earthquake prediction. It is a promising method to predict earthquakes. Some relevantproblems about seismic rnultl-f racial method are discussed also in the paper.
出处
《内陆地震》
1996年第2期103-112,共10页
Inland Earthquake
关键词
地震
分数维
华北地区
时间结构
多分形特征
Earthquake Characteristics of time distribution Fractional dimensionNorth China
