紫坪铺水库地区蓄水前后视应力标度率变化研究
|
摘要
本文利用紫坪铺水库台网记录到的波形资料,计算了2004～2008年170个M_L≥1.0级地震的震源参数.紫坪铺水库震源参数计算结果与其他大陆地区有明显不同:(1)拐角频率远低于其他大陆地区结果,表明库区地震波传播经过了较强的衰减过程;(2)视应力计算结果比其他地区小3个数量级,可能是由于库区地震波的高频成分衰减强烈,低估了能量集中在高频的小地震的地震辐射能量.分析了蓄水前后拐角频率和地震矩以及视应力和地震矩关系(视应力标度率)变化,结果表明:相同地震矩的地震蓄水后拐角频率增加,地震高频成分相对丰富;蓄水前视应力与地震矩的关系不明显,蓄水后视应力随地震矩的增加而增加.视应力标度率的改变可能是蓄水后地震震源物理过程逐渐改变的直接反映.
In this paper, 170 earthquake source parameters of M_L ≥1. 0 were calculated using waveform data observed from 2004 to 2008 by Zipingpu reservoir earthquake network. The result shows great difference to previous results calculated in some continental areas: (1) the corner frequencies are much lower than those in typical continental areas, it tells us that the seismic wave is subjected to great attenuation during propagation; (2) the value of apparent stress is less than other area by 3 orders of magnitude, it may be caused by the severe attenuation of high frequency components of source spectrum which leads to the underestimation of radiated energy. We also analyzed the difference of corner frequency versus seismic moment and apparent stress versus seismic moment before and after reservoir impounding. The corner frequencies of latter are bigger under the same seismic moment. There is no obvious correlation between apparent stress and seismic moment before reservoir impounding, but apparent stress increases with seismic moment after that. The difference of apparent stress scaling law may be a demonstration of transition of focal physical process.
In this paper, 170 earthquake source parameters of M_L ≥1. 0 were calculated using waveform data observed from 2004 to 2008 by Zipingpu reservoir earthquake network. The result shows great difference to previous results calculated in some continental areas: (1) the corner frequencies are much lower than those in typical continental areas, it tells us that the seismic wave is subjected to great attenuation during propagation; (2) the value of apparent stress is less than other area by 3 orders of magnitude, it may be caused by the severe attenuation of high frequency components of source spectrum which leads to the underestimation of radiated energy. We also analyzed the difference of corner frequency versus seismic moment and apparent stress versus seismic moment before and after reservoir impounding. The corner frequencies of latter are bigger under the same seismic moment. There is no obvious correlation between apparent stress and seismic moment before reservoir impounding, but apparent stress increases with seismic moment after that. The difference of apparent stress scaling law may be a demonstration of transition of focal physical process.
引文
[1] 李金龙,邹振轩,张震峰.珊溪水库震群的地震定位.地震地磁观测与研究,2007,28(1) :14～18 Li J L,Zou Z X,Zhang Z F.The earthquake location for Shanxi Reservoir earthquake swarms.Seismological and Geomagnetic Observation and Research(in Chinese),2007,28(1) :14～18
[2] 徐起浩,缪维成,张国荣等.1999年8月河源新丰江M_L4． 9级地震.华南地震,2002,20(2) :57～61 Xu Q H,Miao W C,Zhang G R,et al.The M_L4． 9 Xinfengjiang earthquake,Heyuan in August 1999． South China Journal of Seismology(in Chinese),2002,20(2) :57～61
[3] McGarr A,Fletcher J B.A method for mapping apparent stress and energy radiation applied to the 1944 Northridge earthquake fault zone revisited.Geophys.Res.Lett.,2001,28:3529～2932
[4] McGarr A,Fletcher J B.Mapping apparent stress and energy radiation over fault zones of major earthquakes.Bull.Seism.Soc.Am.,2002,92:1633～1646
[5] 吴忠良.由宽频带辐射能量目录和地震矩目录给出的视应力及其地震学意义.中国地震,2001,17(1) :8～15 Wu Z L.Apparent stress obtained from broadband radiated energy catalogue and seismic moment catalogue and its seismological significance.Earthquake Research in China(in Chinese),2001,17(1) :8～15
[6] Choy G L,Boatwright J L.Global patterns of radiated seismic energy and apparent stress.J.Geophys.Res.,1995,100:18205～18228
[7] Kanamori H,Hauksson E,Hutton L K,et al.Determination of earthquake energy release and M_L using terrascope.Bull.Seis.Soc.Amer.,1993,83(2) :330～346
[8] Izutani Y.Radiated energy from the mid Niigata,Japan,earthquake of October 23,2004,and its aftershocks.J. Geophys.Res.,2005,32(L21313)
[9] Prieto G A,Shearer P M,Vernon F L,et al.Earthquake source scaling and selfsimilarity estimation from stacking P and S spectra.J.Geophys.Res.,2004,109(B08310)
[10] Ide S,Beroza G C.Does apparent stress vary with earthquake size?J.Geophys.Res.,2001,28(17) :3349～3352
[11] 胡先明,谢蓉华.紫坪铺水库地震台网记录地震的复杂性.四川地震,2006,(2) :17～20 Hu X M,Xie R H.Seismic recording complexity of Zhipinpu dam telemetered seismic network.Earthquake Research in Sichuan(in Chinese),2006,(2) :17～20
[12] Atkinson G M,Robert F M.The shape of ground attenuation curves in Southeastern Canada.Bull.Seism.Soc.Amer.,1992,82(5) :2014～2031
[13] Kanamori H,Jim M,Egill H.Determination of earthquake energy release and M_L using terrascope.Bull.Seisrn.Soc.Am.,1993,83(2) :330～346
[14] Wyss M,Brune J N.Seismic moment,stress and source dimensions for earthquakes in the California-Nevada region.J.Geophy.Res.,1968,73:4681～4694
[15] Wyss M.Stress estimates for south American shallow and deep earthquakes.J Geophys.Res.,1970,75(8) :1529～1544
[16] 杨志高,张晓东.首都圈地区地震视应力的计算及空间分布.地震,2009,29(4) :32～43 Yang Z G,Zhang X D.Computation of apparent stress and its spatial distribution in the capital region of China.Earthquake(in Chinese),2009,29(4) :32～42
[17] 陈颐,黄庭芳,刘恩儒.岩石物理学.北京:中国科学技术大学出版社,2009． 64～71 Chen Y,H uang T F,Liu E R.Petrological Physical(in Chinese).Beijing:Petrological Physical,2009． 64～71
[18] Moya A,Aguirre J,Irikura K.Inversion of source parameters and site effects from strong ground motion records using genetic algorithms.Bull.Seism.Soc.Am.,2000,90(4) :977～992
[19] Izutani Y.Radiated energy from the mid Niigata,Japan,earthquake of October 23,2004,and its aftershocks.J.Geophys.Res.,2005,32(L21313)
[20] 周连庆,赵翠萍,陈章立.紫坪铺水库地区尾波Q值研究.地震,2009,29(4) :44～51 Zhou L Q,Zhao C P,Chen Z L.Coda wave Q_C values in the Zipingpu reservoir area,Sichuan province.Earthquake(in Chinese),2009,29(4) :44～51
[21] Aki K.Attenuation of shear waves in the lithosphere for frequencies from 0． 05 to 25 Hz.Phys.Earth Planet,1980,21:50～60
[22] Aki K.Analysis of the seismic coda of local earthquake as scattered waves.J.Geophys.Res.,1969,74(2) :615～631
[23] Jin A S,Aki K.Spatial and temporal correlation between coda Q and seismicity in China.Bull.Seism.Soc.Am., 1988,78(2) :741～769
[24] 黄玉龙,郑斯华,刘 杰等.广东地区地震动衰减和场地响应的研究.地球物理学报,2003,46(1) :54～61 Huang Y L,Zheng S H,Liu J,et al.Attenuation of ground motion and site response in Guang Dong region.Chinese J.Geophys.(in Chinese),2003,46(1) :54～61
[25] 刘红桂,啜永清,陈书清等.鄂尔多斯地块地壳内S波衰减特 征的研究.地震学报,2005,27(5) :488～497 Liu H G,Chuo Y Q,Chen S Q,et al.Attenuation of S waves in the crust of Ordos Massif.Acta Seismological Sinic(in Chinese),2005,27(5) :488～497
[26] Richardson E,Thomas H J.Seismicity in deep gold mines of south africa:implications for tectonic earthquakes.Bull.Seism.Soc.Am.,2002,92(5) :1765～1782
[2] 徐起浩,缪维成,张国荣等.1999年8月河源新丰江M_L4． 9级地震.华南地震,2002,20(2) :57～61 Xu Q H,Miao W C,Zhang G R,et al.The M_L4． 9 Xinfengjiang earthquake,Heyuan in August 1999． South China Journal of Seismology(in Chinese),2002,20(2) :57～61
[3] McGarr A,Fletcher J B.A method for mapping apparent stress and energy radiation applied to the 1944 Northridge earthquake fault zone revisited.Geophys.Res.Lett.,2001,28:3529～2932
[4] McGarr A,Fletcher J B.Mapping apparent stress and energy radiation over fault zones of major earthquakes.Bull.Seism.Soc.Am.,2002,92:1633～1646
[5] 吴忠良.由宽频带辐射能量目录和地震矩目录给出的视应力及其地震学意义.中国地震,2001,17(1) :8～15 Wu Z L.Apparent stress obtained from broadband radiated energy catalogue and seismic moment catalogue and its seismological significance.Earthquake Research in China(in Chinese),2001,17(1) :8～15
[6] Choy G L,Boatwright J L.Global patterns of radiated seismic energy and apparent stress.J.Geophys.Res.,1995,100:18205～18228
[7] Kanamori H,Hauksson E,Hutton L K,et al.Determination of earthquake energy release and M_L using terrascope.Bull.Seis.Soc.Amer.,1993,83(2) :330～346
[8] Izutani Y.Radiated energy from the mid Niigata,Japan,earthquake of October 23,2004,and its aftershocks.J. Geophys.Res.,2005,32(L21313)
[9] Prieto G A,Shearer P M,Vernon F L,et al.Earthquake source scaling and selfsimilarity estimation from stacking P and S spectra.J.Geophys.Res.,2004,109(B08310)
[10] Ide S,Beroza G C.Does apparent stress vary with earthquake size?J.Geophys.Res.,2001,28(17) :3349～3352
[11] 胡先明,谢蓉华.紫坪铺水库地震台网记录地震的复杂性.四川地震,2006,(2) :17～20 Hu X M,Xie R H.Seismic recording complexity of Zhipinpu dam telemetered seismic network.Earthquake Research in Sichuan(in Chinese),2006,(2) :17～20
[12] Atkinson G M,Robert F M.The shape of ground attenuation curves in Southeastern Canada.Bull.Seism.Soc.Amer.,1992,82(5) :2014～2031
[13] Kanamori H,Jim M,Egill H.Determination of earthquake energy release and M_L using terrascope.Bull.Seisrn.Soc.Am.,1993,83(2) :330～346
[14] Wyss M,Brune J N.Seismic moment,stress and source dimensions for earthquakes in the California-Nevada region.J.Geophy.Res.,1968,73:4681～4694
[15] Wyss M.Stress estimates for south American shallow and deep earthquakes.J Geophys.Res.,1970,75(8) :1529～1544
[16] 杨志高,张晓东.首都圈地区地震视应力的计算及空间分布.地震,2009,29(4) :32～43 Yang Z G,Zhang X D.Computation of apparent stress and its spatial distribution in the capital region of China.Earthquake(in Chinese),2009,29(4) :32～42
[17] 陈颐,黄庭芳,刘恩儒.岩石物理学.北京:中国科学技术大学出版社,2009． 64～71 Chen Y,H uang T F,Liu E R.Petrological Physical(in Chinese).Beijing:Petrological Physical,2009． 64～71
[18] Moya A,Aguirre J,Irikura K.Inversion of source parameters and site effects from strong ground motion records using genetic algorithms.Bull.Seism.Soc.Am.,2000,90(4) :977～992
[19] Izutani Y.Radiated energy from the mid Niigata,Japan,earthquake of October 23,2004,and its aftershocks.J.Geophys.Res.,2005,32(L21313)
[20] 周连庆,赵翠萍,陈章立.紫坪铺水库地区尾波Q值研究.地震,2009,29(4) :44～51 Zhou L Q,Zhao C P,Chen Z L.Coda wave Q_C values in the Zipingpu reservoir area,Sichuan province.Earthquake(in Chinese),2009,29(4) :44～51
[21] Aki K.Attenuation of shear waves in the lithosphere for frequencies from 0． 05 to 25 Hz.Phys.Earth Planet,1980,21:50～60
[22] Aki K.Analysis of the seismic coda of local earthquake as scattered waves.J.Geophys.Res.,1969,74(2) :615～631
[23] Jin A S,Aki K.Spatial and temporal correlation between coda Q and seismicity in China.Bull.Seism.Soc.Am., 1988,78(2) :741～769
[24] 黄玉龙,郑斯华,刘 杰等.广东地区地震动衰减和场地响应的研究.地球物理学报,2003,46(1) :54～61 Huang Y L,Zheng S H,Liu J,et al.Attenuation of ground motion and site response in Guang Dong region.Chinese J.Geophys.(in Chinese),2003,46(1) :54～61
[25] 刘红桂,啜永清,陈书清等.鄂尔多斯地块地壳内S波衰减特 征的研究.地震学报,2005,27(5) :488～497 Liu H G,Chuo Y Q,Chen S Q,et al.Attenuation of S waves in the crust of Ordos Massif.Acta Seismological Sinic(in Chinese),2005,27(5) :488～497
[26] Richardson E,Thomas H J.Seismicity in deep gold mines of south africa:implications for tectonic earthquakes.Bull.Seism.Soc.Am.,2002,92(5) :1765～1782
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心