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地震 ›› 1998, Vol. 18 ›› Issue (4): 373-377.

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张北6.2级地震前定点形变异常的动力学特征①

牛安福, 李旭东, 李正媛, 柯丽君   

  1. 中国武汉 430071 中国地震局地震研究所
  • 收稿日期:1998-02-18 修回日期:1998-04-06 发布日期:2022-09-23
  • 作者简介:牛安福,男,1964年8月出生,副研究员,1996年博士生,主要从事地震孕育过程的演化、前兆异常强度定量化、地震预报及深部构造解释研究工作。
  • 基金资助:
    ①地震科学联合基金会资助项目（197066),

THE DYNAMIC CHARACTERISTICS OF DEFORMATION ANOMALY AT FIXED OBSERVATIONAL SITES PRIOR TO THE ZHANGBEI Ms 6.2 EARTHQUAKE

Niu Anfu, Li Xudang, Li Zhengyuan, Ke Lijun   

  1. Institute of Seismology, CSB, Wuhan 430071,China
  • Received:1998-02-18 Revised:1998-04-06 Published:2022-09-23

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摘要： 依据沿近于EW向的燕山断陷带附近的定点形变观测结果,讨论了异常区域分布的动力学特征。结果表明:①在燕山北部块体上的EW向倾斜在震前1年时间尺度内保持相对静止,而NS向则向南加速倾斜,震前0.5年在附近台站出现回跳;②同一测点处二个方向倾斜的发散度在震前2年内出现相似的运动特征,呈减弱趋势;③同一块体不同测点处的异常强度AF值在震前3年间至少出现2次较显著的异常标志。

关键词: 张北地震, 定点倾斜观测, 发散度和异常强度

Abstract: Based on the results of tilting observation in the fault depression of Yanshan mountain, this paper discussed the dynamic features of anomalies in the depression and boundary area. It was demonstrated as follows： ①The relative quiet of tilting along the EW direction and the speeding of tilting toward S along NS direction have been shown one year before Zhangbei Ms 6.2 earthquake, and the sudden rebound of tilting along the NS direction before a half-year has also been detected in the region close to the epicenter； ②The divergence of tilting along the EW and NS directions shows the synchronous movement feature with decreasing tendency two years before the earthquake;③At least two times of obvious anomalous marks expressed by the anomaly intensity AF have been shown at sites in the depression.

Key words: Zhangbei earthquake, Tilting observation at the fixed sites, Divergence and anomaly intensity