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地震 ›› 1998, Vol. 18 ›› Issue (1): 7-13.

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丽江7.0级地震短临异常特征及震源硬化模型

陈立德   

  1. 中国昆明 650041 云南省地震局
  • 收稿日期:1997-02-24 修回日期:1997-04-20 出版日期:1998-01-31 发布日期:2022-05-10
  • 作者简介:陈立德,男,1938年3月出生,研究员,主要从事地震综合预报方法、预报程序指南、震源模型等研究工作。
  • 基金资助:
    本文为国家科委“九五”科研攻关(96-913-01-04-02)课题研究成果

CHARACTERISTICS OF SHORT-TERM AND IMPENDING ANOMALIES FOR LIJIANG EARTHQUAKE WITH M=7. 0 AND FOCAL HARDENING MODEL

Chen Lide   

  1. Seismological Bureau of Yunnan Province, Kunming 650041, China
  • Received:1997-02-24 Revised:1997-04-20 Online:1998-01-31 Published:2022-05-10

摘要: 重点讨论了丽江地震短临预报中识别继承性异常、继承性新异常及新异常的形态特征。同时讨论了判断丽江地震进入短临阶段的判据,如中期趋势异常的结束,巨变异常及异常同步转折等特征。最后,在讨论短临异常时空演化的基础上,结合震中区小震活动的异常平静,短临阶段定点前兆由外向震中迁移,异常外围幅度大、数量多等事实,作者提出了新的震源孕青模型——震源硬化模型。按此模型预测,震源区(余震展布区或地表宏观裂缝展布区)在中短期阶段应出现中小地震的异常平静,元或很少有定点前兆异常显示,但当强震孕育发展到破裂成核时——不可逆失稳阶段,某些地震震源区可能会出现明显的宏观破裂,即地表可见喷沙冒水或前震活动。

关键词: 短临异常, 异常时空演化, 震源硬化模型, 丽江地震

Abstract: During the short-term and impending predictions of Lijiang earthquake ,recognition of the characteristics of successional anomalies , new successional anomalies and new anoma­lies is discussed. Meanwhile, the criteria of anomalies entering the short-term and impend­ing phase,such as the ending of the medium-term anomalies,dramatic anomalies and syn chronous turning, of Lijiang earthquake is also discussed. Finally, based on discussion of time-space evolution of the short-term and impending anomalies, the author has presented a new focal seismogenic model-the focal hardening model.combining the facts mentioned in other papers ,such as anomalous quiescence of small earthquakes within epicentral area, the station-based precursory anomalies migrating from the periphery towards the epicen­ter, anomalies in the periphery having large amplitudes and quantity and so on. According to the model, the anomalous quiescence of small earthquakes should appear during the medium-and short-term phase within the epicentral area (aftershock-distributed or macro­fissure-distributed areas), and no or a few station-based precursory anomalies appear. However, when a strong earthquake is developed towards nucleation of fractures, that is the unreversible unstable phase, distinct macro-fissures probably appear in some focal ar­eas,namely sand-eruption and foreshock activity may appear.

Key words: Short-term and impending anomaly, Time-space evolution of anomaly, Focal hardening model, Lijiang earthquake