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尾波是地震图上的重要现象,它蕴含着有关震源和介质的重要信息。本文根据Aki的单次回弹散射模式,绘制了DD-1短周期地震仪的尾波包络理论量板,订制了综合尾波包络曲线的观测方法,测定了江苏地区的地壳介质的平均品质因子Q。观测表明,尾波包络曲线明显地由两个以上的分支组成,可能分别反映不同深度内地壳介质的平均状态,根据各台测定的Q值作了Q值分布的尝试。结果发现,其中的第一个分支,Q值较低,主要成份可能是面波,其Q_1分布与江苏的地震活动有较好的对应,江苏地震大多发生在Q_1值较大的地区。第二个分支的Q_2值,与由通常地震波Ig衰减求得的Q值相接近,主要成份可能是面波和体波,其分布与地震活动没有明显的对应关系。由于观测条件的限制,没有进一步观测第三、四个支,但其Q值可能更高。本文的观测方法,观测结果的可靠性和普遍性、结果的解释尚有待进一步的检验和不断改进。
The coda wave is an important phenomenon on the seismogram, which contains important information about the source and medium. In this paper, according to Aki’s single springback scattering model, the tail wave envelope theory of DD-1 short-period seismograph is drawn and the observation method of the integrated coda envelope curve is tailored. The average crustal medium in Jiangsu Province Quality factor Q. The observation shows that the coda curve obviously consists of more than two branches and may reflect the average state of the crustal medium in different depths respectively. Based on the measured Q values, the Q value distribution is attempted. The results show that the Q value of the first branch is lower, the main component of which may be a surface wave. The Q_1 distribution has a good correspondence with the seismic activity in Jiangsu Province. Most of the earthquakes in Jiangsu occur in areas with large Q_1 values. The Q 2 value of the second branch is close to the Q value obtained from the attenuation of the normal seismic wave Ig. The main components of the second branch may be surface waves and body waves, and their distribution has no obvious correspondence with the seismic activity. Due to the limitations of observation conditions, there is no further observation of the third and fourth branches, but its Q value may be higher. The observational method, the reliability and universality of the observation results and the interpretation of the results have yet to be further tested and continuously improved.