广东及其邻近区域中小地震应力降研究
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摘要
分析了广东及其邻近地区1999至2004年9月间86个ML≥2.0级地震的应力降值,结果表明,应力降随震级的增大而出现不同尺度的变化,lg△σ的分布大致分为两个阶段:①ML≤4.0级地震,随着震级增大,lg△σ呈增大的趋势;②ML≥4.0级地震,lg△σ不随震级的增大而增大,稳定在一范围内。统计结果表明,本区ML2.0～2.9级地震应力降平均值为4.5bar,ML3.0～3.9级地为7.6 bar,ML4.0～4.9级地震为10.7 bar。2004年阳江ML5.2级地震前1年左右,曾发生多次应力降高于阳江地区平均值的地震事件,而在临震前几个月应力降总体水平则是偏低的,这一特征在其他地区的中强地震前亦曾出现。应力降平面等值线分布图显示北部湾地区是广东及其邻区应力降背景最高的地区。
In this paper,we analyzed the 86 stress drop values of the moderate and small earthquakes(ML≥2.0)occurred between 1999 and Sep.,2004 in Guangdong and its adjacent areas.It shows that the stress drop changes in different extent when the earthquake magnitude increases and the lgΔσ-ML relation chart could be marked off to two phases.1.For the earthquakes with ML≤4.0,lgΔσ increases when the magnitude rises;2.For the earthquakes with ML≥4.0,lgΔσ does not increase but is in some scale when the magnitude rises.It also shows that the mean value of seismic stress drop for ML2.0-2.9 earthquakes in Guangdong and its adjacent areas is 4.5 bar,the one for ML3.0-3.9 is 7.6 bar,the one for ML4.0-4.9 is 10.7 bar.The plane isogram of seismic stress drop shows that the region with the maximum background value in Guangdong and its adjacent areas is the Beibuwan bay.
In this paper,we analyzed the 86 stress drop values of the moderate and small earthquakes(ML≥2.0)occurred between 1999 and Sep.,2004 in Guangdong and its adjacent areas.It shows that the stress drop changes in different extent when the earthquake magnitude increases and the lgΔσ-ML relation chart could be marked off to two phases.1.For the earthquakes with ML≤4.0,lgΔσ increases when the magnitude rises;2.For the earthquakes with ML≥4.0,lgΔσ does not increase but is in some scale when the magnitude rises.It also shows that the mean value of seismic stress drop for ML2.0-2.9 earthquakes in Guangdong and its adjacent areas is 4.5 bar,the one for ML3.0-3.9 is 7.6 bar,the one for ML4.0-4.9 is 10.7 bar.The plane isogram of seismic stress drop shows that the region with the maximum background value in Guangdong and its adjacent areas is the Beibuwan bay.
引文
[1]Atkinson G M,Mereu R F.The shape of ground motion attenuation curves in southeastern Canada[J].Bull Seissm Soc Amer,1992,82:2014-2031
[2]Moya C A,Aguirre J,Irikura K.Inversion of source parameters and site effects from strong ground motion records using genetic algorithms[J].Bull Seism Soc Amer,2000,90(4):977-992.
[3]康英,郑斯华,刘杰,等.中小地震震源参数的求解及其相似关系[J].华南地震,2004,24(2):11-21.
[4]Brune J N.Tectonic stress and the spectra of seismic waves from earthquake[J].J Geophys Res,1970,75:4997-5009.
[5]杨马陵,叶秀薇,叶东华.2001年4月阳江ML4.7级地震的异常与分析[J].华南地震,2003,23(4):37-44.
[6]康英,杨选,吕金水,等.2004年9月17日阳江4.9级地震震源参数分析[J].地震,2005,25(3):109-114.
[7]Z.L.Wu.Scaling of apparent stress from broadband radiated energy catalogue and seismic moment catalogue and its focal mechanism dependence[J].Earth Planets Space,2001,53:943-948.
[8]刘丽芳,秦嘉政.会泽5.3级和文山5.3级地震序列震源参数研究[J].地震研究,2006,29(1):43-49.
[9]秦嘉政,邬成栋,钱晓东.2001年永胜6.0级地震的余震序列应力降研究[J].地震研究,2004,27(2):146-152.
[10]周仕勇,许忠淮.由震源谱推断1997年新疆伽师强震群破裂特性[J].地震学报,2000,22(2):113-124.
[11]高立新,郑斯华,丁风和.内蒙古中西部地区震源参数和场地响应反演[J].西北地震学报,2005,27(2):109-114.
[12]刘丽芳,刘杰,苏有锦.姚安地震序列与大姚序列震源参数的对比研究[J].地震,2006,26(1):10-18.
[13]王雄健,郑沃参.阳江市洋边海2001年4月22日ML4.6级地震影响场[J].华南地震,2002,22(2):87-89.
[14]肖蔚文.1982年卢龙地震前后的小震震源参数[J].地震学报,1990,12(1):1-11.
[15]张天中,马云生,黄蓉良,等.1995年徒河地震前后小震震源参数及其相互关系[J].地震学报,2000,22(3):233-240.
[16]徐起浩,华卫,万永芳,等.广东省及邻区新生代以来构造运动与地震活动的分区研究[J].水文地质工程地质,2004,31(4):33-40.
[2]Moya C A,Aguirre J,Irikura K.Inversion of source parameters and site effects from strong ground motion records using genetic algorithms[J].Bull Seism Soc Amer,2000,90(4):977-992.
[3]康英,郑斯华,刘杰,等.中小地震震源参数的求解及其相似关系[J].华南地震,2004,24(2):11-21.
[4]Brune J N.Tectonic stress and the spectra of seismic waves from earthquake[J].J Geophys Res,1970,75:4997-5009.
[5]杨马陵,叶秀薇,叶东华.2001年4月阳江ML4.7级地震的异常与分析[J].华南地震,2003,23(4):37-44.
[6]康英,杨选,吕金水,等.2004年9月17日阳江4.9级地震震源参数分析[J].地震,2005,25(3):109-114.
[7]Z.L.Wu.Scaling of apparent stress from broadband radiated energy catalogue and seismic moment catalogue and its focal mechanism dependence[J].Earth Planets Space,2001,53:943-948.
[8]刘丽芳,秦嘉政.会泽5.3级和文山5.3级地震序列震源参数研究[J].地震研究,2006,29(1):43-49.
[9]秦嘉政,邬成栋,钱晓东.2001年永胜6.0级地震的余震序列应力降研究[J].地震研究,2004,27(2):146-152.
[10]周仕勇,许忠淮.由震源谱推断1997年新疆伽师强震群破裂特性[J].地震学报,2000,22(2):113-124.
[11]高立新,郑斯华,丁风和.内蒙古中西部地区震源参数和场地响应反演[J].西北地震学报,2005,27(2):109-114.
[12]刘丽芳,刘杰,苏有锦.姚安地震序列与大姚序列震源参数的对比研究[J].地震,2006,26(1):10-18.
[13]王雄健,郑沃参.阳江市洋边海2001年4月22日ML4.6级地震影响场[J].华南地震,2002,22(2):87-89.
[14]肖蔚文.1982年卢龙地震前后的小震震源参数[J].地震学报,1990,12(1):1-11.
[15]张天中,马云生,黄蓉良,等.1995年徒河地震前后小震震源参数及其相互关系[J].地震学报,2000,22(3):233-240.
[16]徐起浩,华卫,万永芳,等.广东省及邻区新生代以来构造运动与地震活动的分区研究[J].水文地质工程地质,2004,31(4):33-40.
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