地震成因的综合模型和强震预报

COMPREHENSIVE MODEL OF EARTHQUAKE FORMING MECHANISM AND STRONG EARTHQUAKE PREDICTION

摘要:

根据以往研究的地震孕育和发生的3个模式提出了地震成因的综合模式、地震前兆指标和预报方法。综合模式由7个单元组成:震源、震源端部的2个调整单元、震源顶部和底部的2个软弱层(这些单元均位于上岩石圈)以及下岩石圈的两个深部剪切蠕滑断层(一个与震源断层面垂直立交,另一个与震源断层面同面立接)。这7个单元组成了导致强震后果的结构。在构造力源作用下每一个单元围绕震源运动。最终使震源区破裂和发生强震。根据这个模式各种地震前兆异常区的演化与模式中震源与其它各个单元之间的差异性有关,与调整单元、调整层、深部剪切蠕滑断层之间的差异性有关。这种差异性使不同时间或同一时段多个异常区、带边界的交汇点或连接区预示未来强震位置。
在孕震后期,震源系统某些单元之间的相互作用增强,并形成正反馈,前兆异常随时间的变化出现起伏加剧。根据总结,强震大多发生在第3次起伏加剧的峰值处和峰值后并得到
M=4.29+0.11t
式中t为起伏加剧的异常时间,以月为单位。由上述指标可以作出强震的中短期预报。在文章最后我们以唐山地震为例展示了综合模式在地震预报中的应用。

Abstract:

On the basis of previous research on three earthquake source preparation and occurrence models, the comprehensive model about earthquake forming mechanism,earthquake prediction indexes and prediction methodology have been suggested in the present paper. Comprehensive model consists of 7 major units:the earthquake source, two adjustment elements at ends of source region, two weak medium layers above and below the source body,which are located in upper lithosphere, and two deep shear creep faults in lower lithosphere, in which one is perpendicularly stereoscopically crossed with the seismogenic fault and another parallel to it in the same plane. The 7 basic units compose a structure having strong earthquakes.
According to this model, the differentiation between the source region and the other units and the differentiation among the adjustment elemonts, adjustment layers and deep shear creep faults can lead to temporal and spatial evolution of earthquake source and the boundary of various seismic precursory anomalies regions will pass through the source region. The intersection region of several boundaries of various seismic precursory anomalies regions in various time interval is epicenter of future strong earthquake.
During latter preparation period, the interaction between some units of the model intensifies and forms positive feedback, and the fluctuation intensification anomalies of precursor change with time. According to our study, the main shock occurs generally just at the third peak of fluctuation intensification of precursor or after it,and fluctuation intensification displays certain periodicity. Therefore we can estimate roughly the third peak time and get formula
M=4.29 +0.11t
t indicates anomalous time interval of fluctuation intensification, in month. According to above mentioned indexes, the moderate and short term prediction of strong earthquake may be made. At the end of this paper, we take the 1976 Tangshan earthquake as an example to show the application of the comprehensive model in the earthquake prediction.