河北文安MS5.1地震前首都圈及邻区震源动力学参数时空变化特征
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摘要
本文根据近震源条件下,由北京数字遥测地震台网观测到的波形资料,利用Brune模式,得到了2002年1月至2006年6月期间首都圈及邻近地区989次ML≥2.0地震的震源谱,测定了它们的拐角频率和零频幅值。通过相关计算公式,得到了破裂半径、地震矩、地震能量、应力降、视应力等震源动力学参数。分析了这些动力学参数的标度关系以及在2006年7月4日河北文安MS5.1地震前的时空变化特征。结果表明,文安MS5.1地震前,视应力、应力降、地震能量与破裂半径比等出现了相对高值集中区,这些高值集中区主要分布在华北平原带上;从时间变化曲线可以看出,文安MS5.1地震前华北平原带上视应力、应力降、地震能量与破裂半径比等参数都表现出了明显的升高变化过程,而拐角频率则显示出趋势性下降变化特征。这可能与文安MS5.1地震前华北平原带上应力的增强过程有关。
Based on near-source conditions,we used waveform data observed by the Beijing Digital Telemetry Seismic Network and obtained source spectrum,corner frequency and zero frequency amplitude values of 989 earthquakes with magnitude larger than ML2.0 occurred in the capital circle of China and surrounding area from January 2002 to June 2006 by the Brune model.Some relevant formulas had been used for calculation of a few focal dynamic parameters,such as rupture radius,seismic moment,seismic energy,stress drop,apparent stress,and so on.The scaling relations of these dynamic parameters and characters of the temporal-spatial variations before the Wen′an MS5.1 earthquake in Hebei Province of July 20,2006 had been analyzed.Results show that apparent stress,stress drop,seismic energy and rupture radius ratio appeared relatively high in some focus areas before the Wen′an MS5.1 earthquake.These areas were mainly distributed in the North China Plain.It could be seen from the time curves that apparent stress,stress drop,seismic energy and rupture radius ratio and other parameters had shown a significant increasing process before the Wen′an MS5.1 earthquake,but corner frequency showed a trend of decreased variation.This result might be related to the increasing process of stress in the North China Plain before the Wen′an MS5.1 earthquake.
Based on near-source conditions,we used waveform data observed by the Beijing Digital Telemetry Seismic Network and obtained source spectrum,corner frequency and zero frequency amplitude values of 989 earthquakes with magnitude larger than ML2.0 occurred in the capital circle of China and surrounding area from January 2002 to June 2006 by the Brune model.Some relevant formulas had been used for calculation of a few focal dynamic parameters,such as rupture radius,seismic moment,seismic energy,stress drop,apparent stress,and so on.The scaling relations of these dynamic parameters and characters of the temporal-spatial variations before the Wen′an MS5.1 earthquake in Hebei Province of July 20,2006 had been analyzed.Results show that apparent stress,stress drop,seismic energy and rupture radius ratio appeared relatively high in some focus areas before the Wen′an MS5.1 earthquake.These areas were mainly distributed in the North China Plain.It could be seen from the time curves that apparent stress,stress drop,seismic energy and rupture radius ratio and other parameters had shown a significant increasing process before the Wen′an MS5.1 earthquake,but corner frequency showed a trend of decreased variation.This result might be related to the increasing process of stress in the North China Plain before the Wen′an MS5.1 earthquake.
引文
[1]Frank S,K Carl.Variations of apparent stresses and stress drops prior to the earthquake of 6May1984(mb=5.8)in the Adak seismic zone[J].Bull Seism Soc Am,1984,74(6):2 577-2 592.
[2]Vyacheslav M Z.Apparent stress of earthquakes within the shallow subduction zone near KamchatkaPeninsula[J].Bull Seism Soc Am,1996,86(3):811-820.
[3]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[J].中国地震,2001,17(1):8-15.
[4]吴忠良,黄静,林碧苍.中国西部地震视应力的空间分布[J].地震学报,2002,24(3):293-301.
[5]Wu Z L.Scaling of apparent stress from broadband radiated energy catalogue and seismic momentcatalogue and its focal mechanism dependence[J].Earth Planets Space,2001,53:943-948.
[6]Basil N M,Hatzidimitriou P M.Source Spectral Scaling and Stress Release Estimates Using Strong-Motion Records in Greece[J].Bull Seism Soc Am,2002,92(3):1 040-1 059.
[7]陈学忠,王小平,王林瑛,等.地震视应力用于震后趋势快速判定的可能性[J].国际地震动态,2003,295(7):1-4.
[8]吴晶,顾瑾萍.甘肃景泰MS5.9地震前后小地震视应力计算讨论[J].地震,2004,24(1):171-175.
[9]钟羽云,张帆,张震峰,等.应用强震应力降和视应力进行震后趋势快速判定的可能性[J].防灾减灾工程学报,2004,24(1):8-14.
[10]陈学忠,许向彤,翟文杰.1995年7月20日河北沙城ML4.1地震序列破裂过程中应力变化的研究[J].地震学报,2005,27(3):276-281.
[11]陈学忠.2001年昆仑山口西8.1级大地震前后震源区应力水平估计[J].地震学报,2005,27(6):605-609.
[12]王琼,陈学忠,王林瑛.岫岩地震序列视应力变化及其预测意义[J].地震,2005,25(3):91-97.
[13]程万正,陈学忠,乔慧珍.四川地震辐射能量和视应力研究[J].地球物理学进展,2006,21(3):692-699.
[14]刘红桂,刘杰,丁页岭,等.地震视应力在云南地震序列中的前兆特征[J].地震学报,2006,28(5):462-471.
[15]乔慧珍,程万正,陈学忠.安宁河-则木河断裂带地震视应力研究[J].地震研究,2006,29(2):125-130.
[16]秦嘉政,钱晓东.云南地区地震视应力的时间和空间分布研究[J].地震学报,2006,28(3):221-229.
[17]刘红桂,王培玲,杨彩霞,等.地震视应力在地震预测中的应用[J].地震学报,2007,29(4):437-445.
[18]陈学忠,李艳娥.2006年7月4日河北文安MS5.1地震前震中周围地区小震视应力随时间的变化[J].中国地震,2007,23(4):327-336.
[19]李艳娥,陈学忠.1999年11月29日岫岩5.4级地震序列震源参数测定及标度关系分析[J].地震,2007,27(4):59-67.
[20]孙燕萍,史勇军.新疆两次强震前后地震视应力变化[J].地震地磁观测于研究,2007,28(4):20-28.
[21]张彬,杨选辉.中国大陆地震视应力空间分布研究[J].大地测量与地球动力学,2007,27(5):26-30.
[22]盛书中,万永革.地震视应力及其物理意义的探讨[J].地震地磁观测与研究,2008,29(1):36-43.
[23]Jiménez A,Garcia J M,Romacho M D.Simultaneous inversion of source parameters and attenuationfactor using genetic algorithms[J].Bull Seism Soc Am,2005,95(4):1 401-1 411.
[24]Aki K,Richards P G.Quantitative Seismology,Theory and Methods[M].Freeman&CompanySan Francisco,California.1980.
[25]Andrews D J.Objective determination of source parameters and similarity of earthquakes of differentsize[A].In:Das S,Boatwright J and Scholz C H(eds),Earthquake Source Mechanics[C].Wash-ington,D C,A G U,1986,259-267.
[26]Snoke J A.Stable determination of(Brune)stress drop[J].Bull Seism Soc Am,1987,77(2):530-538.
[27]Wyss M.Apparent stresses of earthquakes on ridges compared to apparent stresses of earthquakes intrenches[J].Geophys J R.astr Soc,1970,19:479-484.
[28]Archuleta R,Cranswick E,Mueller C,et al.Source parameters of the 1980Mammoth Lakes,Cali-fornia,earthquakes sequence[J].J Geophys Res,1982,87:4 595-4 607.
[2]Vyacheslav M Z.Apparent stress of earthquakes within the shallow subduction zone near KamchatkaPeninsula[J].Bull Seism Soc Am,1996,86(3):811-820.
[3]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[J].中国地震,2001,17(1):8-15.
[4]吴忠良,黄静,林碧苍.中国西部地震视应力的空间分布[J].地震学报,2002,24(3):293-301.
[5]Wu Z L.Scaling of apparent stress from broadband radiated energy catalogue and seismic momentcatalogue and its focal mechanism dependence[J].Earth Planets Space,2001,53:943-948.
[6]Basil N M,Hatzidimitriou P M.Source Spectral Scaling and Stress Release Estimates Using Strong-Motion Records in Greece[J].Bull Seism Soc Am,2002,92(3):1 040-1 059.
[7]陈学忠,王小平,王林瑛,等.地震视应力用于震后趋势快速判定的可能性[J].国际地震动态,2003,295(7):1-4.
[8]吴晶,顾瑾萍.甘肃景泰MS5.9地震前后小地震视应力计算讨论[J].地震,2004,24(1):171-175.
[9]钟羽云,张帆,张震峰,等.应用强震应力降和视应力进行震后趋势快速判定的可能性[J].防灾减灾工程学报,2004,24(1):8-14.
[10]陈学忠,许向彤,翟文杰.1995年7月20日河北沙城ML4.1地震序列破裂过程中应力变化的研究[J].地震学报,2005,27(3):276-281.
[11]陈学忠.2001年昆仑山口西8.1级大地震前后震源区应力水平估计[J].地震学报,2005,27(6):605-609.
[12]王琼,陈学忠,王林瑛.岫岩地震序列视应力变化及其预测意义[J].地震,2005,25(3):91-97.
[13]程万正,陈学忠,乔慧珍.四川地震辐射能量和视应力研究[J].地球物理学进展,2006,21(3):692-699.
[14]刘红桂,刘杰,丁页岭,等.地震视应力在云南地震序列中的前兆特征[J].地震学报,2006,28(5):462-471.
[15]乔慧珍,程万正,陈学忠.安宁河-则木河断裂带地震视应力研究[J].地震研究,2006,29(2):125-130.
[16]秦嘉政,钱晓东.云南地区地震视应力的时间和空间分布研究[J].地震学报,2006,28(3):221-229.
[17]刘红桂,王培玲,杨彩霞,等.地震视应力在地震预测中的应用[J].地震学报,2007,29(4):437-445.
[18]陈学忠,李艳娥.2006年7月4日河北文安MS5.1地震前震中周围地区小震视应力随时间的变化[J].中国地震,2007,23(4):327-336.
[19]李艳娥,陈学忠.1999年11月29日岫岩5.4级地震序列震源参数测定及标度关系分析[J].地震,2007,27(4):59-67.
[20]孙燕萍,史勇军.新疆两次强震前后地震视应力变化[J].地震地磁观测于研究,2007,28(4):20-28.
[21]张彬,杨选辉.中国大陆地震视应力空间分布研究[J].大地测量与地球动力学,2007,27(5):26-30.
[22]盛书中,万永革.地震视应力及其物理意义的探讨[J].地震地磁观测与研究,2008,29(1):36-43.
[23]Jiménez A,Garcia J M,Romacho M D.Simultaneous inversion of source parameters and attenuationfactor using genetic algorithms[J].Bull Seism Soc Am,2005,95(4):1 401-1 411.
[24]Aki K,Richards P G.Quantitative Seismology,Theory and Methods[M].Freeman&CompanySan Francisco,California.1980.
[25]Andrews D J.Objective determination of source parameters and similarity of earthquakes of differentsize[A].In:Das S,Boatwright J and Scholz C H(eds),Earthquake Source Mechanics[C].Wash-ington,D C,A G U,1986,259-267.
[26]Snoke J A.Stable determination of(Brune)stress drop[J].Bull Seism Soc Am,1987,77(2):530-538.
[27]Wyss M.Apparent stresses of earthquakes on ridges compared to apparent stresses of earthquakes intrenches[J].Geophys J R.astr Soc,1970,19:479-484.
[28]Archuleta R,Cranswick E,Mueller C,et al.Source parameters of the 1980Mammoth Lakes,Cali-fornia,earthquakes sequence[J].J Geophys Res,1982,87:4 595-4 607.
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