大同地震前后介质Q值和小震震源参数的变化  

VARIATION OF Q-VALUE IN THE CRUST AND STRESS-DROP OF SMALL SHOCKS AROUND DATONG EARTHQUAKE

作　　者：韦士忠 李玉萍[1] 

机构地区：[1]国家地震局地球物理研究所

出　　处：《地震》1992年第2期30-38,共9页Earthquake

基　　金：地震科学联合基金(89386)

摘　　要：本文使用北京台网微机数字记录,通过波谱分析研究了大同地震前后介质Q值和小震应力降的变化。研究结果表明:(1)大同地震发生在低Q值区,震前Q值升高,震后恢复正常。(2)大同地震前,小震应力降明显升高,震后恢复正常,震前震后应力降的变化与介质Q值变化和应力变化有关。(3)大同地震前后小震震源参数确实有明显不同,无论是应力降、平均位错还是震源尺度都有明显不同。(4)大同地震前后小震波谱有明显变化。Through spectral analysis, we studied variations of Q-value in the crust and stress-drop of small shocks using the digital records of the Beijing network in this paper. The research-results show: 1. The Datong earthquake occurred in the low Q-value region, the Q-value increased before the main shock and returned to the normal level after the main shock; 2. The stress-drop of small earthquakes increased obviously before the main shock and returned to the normal level after the main shock. The variation of stress-drop around the main shock was in relation to the changes of Q-value and stress in the crust.; 3. The focal parameters of small shocks, such as stress-drop, average dislocation or source dimension around the Datong earthquake were obviously different; 4. The spectrum of small shocks also changed obviously before and after the Datong earthquake.

关 键 词：地震 介质 Q值 震源参数 变化 

分 类 号：P316.2[天文地球—地震学]