| 孕震介质中地震波振幅特性的某些理论与实际研究 |
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| 引用本文： | 李清河,冯德益.孕震介质中地震波振幅特性的某些理论与实际研究[J].西北地震学报,1982,4(1):24-39. |
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| 作者姓名： | 李清河 冯德益 |
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| 作者单位： | 兰州地震研究所，兰州地震研究所 兰州地震研究所地震波理论与应用研究生 |
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| 摘 要： | 本文提出了孕震介质的理论模型,建立了两相介质中的力学关系和运动方程,论证了孕震介质中两类P波的性质,推导了多相层状介质中地震波传播的反射和折射系数,讨论了参数选取办法並计算了孕震介质中的位移场。具体分析了1975年2月4日海城地震前振幅比变化的吋、空特性,尤其是临震异常特性。並从物理实质上对振幅比异常作了初步解释。
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A THEORETICAL AND PRACTICAL STUDY ON THE AMPLITUDE CHARACTERISTICS OF SEISMIC WAVES IN THE DEVELOPING EARTHQUAKE MEDIA |
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| Li Qing-he and Feng De-yi.A THEORETICAL AND PRACTICAL STUDY ON THE AMPLITUDE CHARACTERISTICS OF SEISMIC WAVES IN THE DEVELOPING EARTHQUAKE MEDIA[J].Northwestern Seismological Journal,1982,4(1):24-39. |
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| Authors: | Li Qing-he and Feng De-yi |
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| Institution: | The Seismological Institute of Lanzhou and The Seismological Institute of Lanzhou |
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| Abstract: | In this paper,the theoretical model for the developing earthquake media has been proposed and the mechanics relations and motion equation intwo-phase media have been established.The properties of two-kind p-waves in the developing earthquake media have been demonstrated.The authors have studied also the reflective and refractive coefficients for propagation of seismic waves in the layered multi-phase media.The methods for selecting parameteres have been discussed and The displacement field in the developing earthquake media calculated.Specifically,for instance,the authors have analysed the temporal and spatial characteristics of the amplitude ratio,including those of the imminent shock anomaly before and after the Haicheng earthquake of February 4.1975 Finally,the amplitude ratio anomaly is interpreted preliminarily from the point of view of physical implication.Theoretical and practical results show that (1) The seismic velocities,amplitudes and waveforms may variate when they travel through the developing earthquake media,especially,the variations of the p-amplitude are bigger.The variations of amplitude ratio depend mainly on the variations of p-amplitude.In the two-phase media with gas saturation,the p-amplitude is bigger than in the solid-phase,oppositely,in the two-phase media with liquid-saturation the p-amplitude is less than in the solid-phase.(2) The forms of the temporal variation before and after the Haicheng earthquake appeared as follows:lower value and then revalue-higher and stable value-occurence of shock-falling.The spatial variation was that the amplitude ratio in the periphery was lower,in the middle higher,the fringe on the high-value region was a dangerous region of major shcok.(3) The amplitude retio increased sharply before imminent shock and earthquak occured when the amplitude peak was falling.The time for appearing peak depended on the epicentral distance and azimuth Generally,it appeared in periphery and in some position at first and then in epicentral area.Based on the preceding coclusions the possibility that the amplitude ratio as a pre cursor may be applied to earthpuakes prediction has increased. |
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