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地震 ›› 2003, Vol. 23 ›› Issue (2): 70-76.

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强震前形变异常的时空演化特征*

宋先月1, 宋治平1, 武安绪2, 薛艳3, 倪友忠1   

  1. 1.上海市地晨局, 上海 200062;
    2.北京市地震局,北京 100081;
    3.中国地晨局分析预报中心,北京 1 00036
  • 收稿日期:2002-05-08 修回日期:2002-07-01 出版日期:2003-04-30 发布日期:2021-12-21
  • 作者简介:宋先月(1976-）,男,湖北巴东人,助理研究员,主要从事地震预报等的研究与应用。
  • 基金资助:
    “十五“ 国家科技攻关项目l200lBA60lBOl-04-02); 地震科学联合基金项目(101105)

The temporal -spatia] evolution characteristics of defor-mation anomal y before strong earthquakes

SONG Xian-yue1, SONG Zhi-ping1, WU An-xu2, XUE Yan3, NI You-zhong1   

  1. 1. Seismological Bureau of Shanghai Municipality; Shanghai 200062;
    2. Seismological Bureau of Beijing Municipality, Beijing 100081, China;
    3. Center for Analysis and Prediction, Beijing 100036, China
  • Received:2002-05-08 Revised:2002-07-01 Online:2003-04-30 Published:2021-12-21

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摘要： 主要对华北北部地区的1989年大同地震、1991 年大同地震及1998年张北地震3次强震前的形变异常时空演化特征进行了研究。结果表明,若以形变异常的开始时间作为判断标准,形变异常的群体频次在强震前1~2年内均出现高于或接近2倍均方差的高值状态,显示出形变异常的中期异常,异常时空演化的三阶段特征表现不明显。若以形变异常的转折时间(或结束时间)作为异常判断标准,形变异常频次在震前1~4个月达到高值,显示出异常的短临信息,并且,形变异常的时空演化过程存在明显的三阶段(a、β、Y)特征。在对这些特征进行理论分析的基础上,提出了将形变异常的开始时间与转折时间分别作为判断标准,如果两种群体频次均处于异常状态,则表明异常已处于从中期向短期过渡的阶段,反之.异常仍处于中期阶段。这种形变异常的分析思路可作为形变异常从中期阶段向短期阶段过渡的-种判断方法。

关键词: 强震前形变异常, 时空演化特征, 异常开始时间, 异常转折时间

Abstract: This paper mainly discusses the temporal-spatial evolution characteristics of defor-mation anomaly before the Datong earthquakes in 1989, 1991 and the Zhangbei eart hquake in1998. The results show that, if the start time of anomaly is taken as a judgment criterion, thefrequency of deformation anomaly is usually higher than or near twice mean square deviationduring 1~ 2 years before strong earthquakes. That is, this shows the mid-term anomaly of de-formation, which the 3-stages characteristics in the temporal-spatial evolution process are notobvious. If the time of turning point or end time of the deformation anomaly is taken as thejudgment criterion, the frequency of deformation anomaly will come to the maximum value 1~ 4 months before the earthquakes. This shows the short- term information and obvious 3-stages characteristics(a, ß, y). Based on the theoretical analysis of these features, the start-ing time and the time of turning point may be taken as the judgment criterion respectijvely. Ifthe frequencies obtained by two methods are all anomalous, it indicates the anomaly is in thetransitional stage from mid-term to the short-term. Otherwise, it is in the mid-term stage.This analytical idea can be used to judge the transitional stage from mid-term to the short-termof deformation anomaly.

Key words: Deformation anomaly before strong earthquakes, Temporal-spatial evolutioncharacteristics, Starting time of anomaly, The time turning point abnormity

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