甘肃近期2次中强震前后震源区微震尾波(Q_c)的变化特征
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摘要
利用张掖台网和天祝 -古浪台网的记录资料研究了 1988年 11月 2 2日肃南 5 .7级地震和 1996年 6月 1日天祝 -古浪 5 .4级地震前后震源区微震尾波 Qc值的变化特征 ,结果表明 :5 .7级地震前震源及邻近地区介质 1/ Qc值趋于一致 ,认为这是该次地震的一种前兆表现 ,结合该次地震的震源机制和构造情况进行了讨论。天祝 -古浪 5 .4级地震震源区附近地区微震尾波 Qc值与频率的关系表明 ,这一地区属于构造活动地区。
The variation characteristics of the coda Q c values of micro earthquakes in the source areas before and after two earthquakes.The two events are Sunan earthquake(M5.7,Nov.22,1988)and Tianzhu Gulang earthquake(M5.4,June 1,1996).The results show that the 1/Q c values tend to identity in the source and its near area before the earthquake M5.7.It is considered that it is a precursor before the earthquake and discussed combining with the source mechanism of this earthquake and the tectonics in the area. The relation between the coda 1/Q c values near the source area of Tianzhu Gulang earthquake and the frequencies have been studied,it shows that the studied area belongs to active tectonic area.
The variation characteristics of the coda Q c values of micro earthquakes in the source areas before and after two earthquakes.The two events are Sunan earthquake(M5.7,Nov.22,1988)and Tianzhu Gulang earthquake(M5.4,June 1,1996).The results show that the 1/Q c values tend to identity in the source and its near area before the earthquake M5.7.It is considered that it is a precursor before the earthquake and discussed combining with the source mechanism of this earthquake and the tectonics in the area. The relation between the coda 1/Q c values near the source area of Tianzhu Gulang earthquake and the frequencies have been studied,it shows that the studied area belongs to active tectonic area.
引文
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[9 ] 李松林 ,等 .滦县地区尾波 Q值及其与频率关系的研究 [J] .地震学报 ,1 990 ,1 2 (4) :357～ 366
[2 ] Aki,Scattering and attenuation of shear waves in the lithosphere[J] .J. Geophys.Res.1 980 ,85:6496～ 6540 .
[3] Aki and Chouet.Origin of coda wave:source,attenuation and scattering effects[J] .J.G.R,1 975,88:332 2～ 3342 .
[4] 曾健 ,等 .单次与多次散射对地方震尾波的作用 [J] .地震学报 ,1 988,1 1 (1 ) :1 2～ 1 3.
[5] 聂永安 ,等 .三维尾波散射问题的理论研究 [J] .地震学报 ,1 995,1 7(1 ) :83～ 87.
[6] Rautian and Khalturin. The use of coda for determination of the earthquake source spectrum[J] .Bull.Seismol.Soc.Am,1 978,68:92 3～ 940 .
[7] 高元勤 ,等 . 1 988年 1 2月 2 2日甘肃肃南 5.7及地震 [J] .西北地震学报 ,1 989,1 1 (3) :78～ 81 .
[8] 高龙生 ,等 .唐山 -北京地区 Q因子随频率的变化 [J] .地震学报 ,1 9866,8(4) :354～ 365.
[9 ] 李松林 ,等 .滦县地区尾波 Q值及其与频率关系的研究 [J] .地震学报 ,1 990 ,1 2 (4) :357～ 366
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