郯庐断裂带南段及邻区中小地震视应力的时空特征研究
|
摘要
利用安徽地区测震台网记录的波形资料,采用波形分析和反演的方法计算了郯庐断裂带南段及邻区中小地震的视应力,分析研究视应力的时空变化特征,并讨论其与地震矩等震源参数之间的关系。结果表明:①利用提取的地震震源谱数据计算得到郯庐断裂带南段及邻区中小地震的视应力值为0.05～0.9MPa,平均为0.20MPa,以此可作为该区域的背景应力水平;②时间变化显示视应力在黄海ML5.1、江西九江ML6.0及河南太康ML5.0地震前呈现持续高值异常状态,震后趋于正常水平,而江西九江6.0级地震后视应力再次出现高值异常,随后发生了安徽定远ML4.7地震,一定程度上说明郯庐断裂南段及邻区中小地震的高视应力水平与华东地区中强震有较好的对应关系;③空间分布显示高视应力集中区与地震高辐射能区域具有一定的相关性,主要位于嘉山—滁州段的皖、苏交界区附近和庐江县附近,该区域相继发生过定远4.7级和安庆4.8级地震,并推断认为庐江县附近发生破坏性地震的危险性可能更大,值得高度关注;④视应力随着地震矩增加而增加的趋势不明显,拐角频率与地震矩大体呈负相关。
Based earthquake data recorded by the Anhui seismic network,using waveform analysis and inversion,we calculated small to moderate earthquake apparent stresses in the south part of the Tanlu fault belt and adjacent areas,analyzed their variation characteristics in time and space,discussed the corresponding relationship with earthquake moment and source parameters.The results show: ① Using earthquake source spectrum data,the obtained apparent stress value in the south part of Tanlu fault belt and adjacent areas is between 0.05~0.9 MPa,averaging 0.20 MPa,which is the background stress level of the region;② Temporal change shows apparent stresses continued to present abnormally high values before Huang Hai ML5.1 earthquake,Jiangxi Jiujiang ML6.0 earthquake and Henan Taikang ML5.0 earthquake,to be normal after earthquake.But after Jiangxi Jiujiang magnitude 6 earthquake,apparent stresses have again a high value anomaly,subsequently Anhui Dingyuan ML4.7 earthquake happened,to a certain extent show that the high level of apparent stress in the south part of the Tanlu fault belt and adjacent areas have a good corresponding relationship with strong earthquakes in East China;③ Spatial distribution shows high value area of apparent stress is relevant to the seismic radiation energy higher area,mainly lied in Jiashan-Chuzhou section and Lujiang county nearby,where Dingyuan magnitude 4.7 earthquake and Anqing magnitude 4.8 earthquake happened in succession;④ It is not obvious that apparent stress increases with earthquake moment,corner frequency basically has a negative correlation with earthquake moment.
Based earthquake data recorded by the Anhui seismic network,using waveform analysis and inversion,we calculated small to moderate earthquake apparent stresses in the south part of the Tanlu fault belt and adjacent areas,analyzed their variation characteristics in time and space,discussed the corresponding relationship with earthquake moment and source parameters.The results show: ① Using earthquake source spectrum data,the obtained apparent stress value in the south part of Tanlu fault belt and adjacent areas is between 0.05~0.9 MPa,averaging 0.20 MPa,which is the background stress level of the region;② Temporal change shows apparent stresses continued to present abnormally high values before Huang Hai ML5.1 earthquake,Jiangxi Jiujiang ML6.0 earthquake and Henan Taikang ML5.0 earthquake,to be normal after earthquake.But after Jiangxi Jiujiang magnitude 6 earthquake,apparent stresses have again a high value anomaly,subsequently Anhui Dingyuan ML4.7 earthquake happened,to a certain extent show that the high level of apparent stress in the south part of the Tanlu fault belt and adjacent areas have a good corresponding relationship with strong earthquakes in East China;③ Spatial distribution shows high value area of apparent stress is relevant to the seismic radiation energy higher area,mainly lied in Jiashan-Chuzhou section and Lujiang county nearby,where Dingyuan magnitude 4.7 earthquake and Anqing magnitude 4.8 earthquake happened in succession;④ It is not obvious that apparent stress increases with earthquake moment,corner frequency basically has a negative correlation with earthquake moment.
引文
[1]Wyss M,Brune J N.Seismicmoment,stres,and source dimensions for earthquakes in the Califor-nia-Nevada region[J].J Geophys Res,1968,73:4 681-4 694.
[2]Mc Garr A.On relating apparent stress to the stress causing earthquake fault slip[J].J GeophysRes,1999,104:3 003-3 011.
[3]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.
[4]黄显良,刘东旺,沈小七,等.华东地区视应力场的研究[J].地震地磁观测与研究,2005,26(6):29-32.
[5]陈宇卫,张军,庆梅,等.“霍山地震窗”小震序列运动学参数时变特征研究[J].地震,2007,27(1):26-32.
[6]曹凤娟,尹涛,马丽.岫岩MS5.4地震前后视应力时空变化特征[J].东北地震研究,2005,21(1):14-19.
[7]李清河,黄耘,张元生,等.郯庐断裂带中南段速度结构特点[J].国际地震动态,2008,30(11):110-110.
[8]张毅,翟洪涛,顾春雷,等.郯庐断裂带中南段重磁综合剖面探测研究[J].国际地震动态,2011,387(3):10-11.
[9]Atkinson G M,Mereu R F.The shape of ground motion attenuation curves in southeastern Canada[J].BSSA,1992,82:2 014-2 031.
[10]黄玉龙,郑斯华,刘杰.广东地区地震动衰减和场地响应的研究[J].地球物理学报,2003,46(1):54-61.
[11]沈小七,刘杰,陈宇卫,等.安徽地区地震波衰减、场地响应及震源新参数的测定[J].地震地磁观测与研究,2005,26(3):1-10.
[12]郑先进,刘东旺,沈小七,等.安徽地区尾波Qc值特征研究[J].华北地震科学,2011,29(3):8-12.
[13]Andrews D J.Objective determination of source parameters and similarity of earthquakes of diferentsize[A].In:Das S,Boatwright J,Scholz C H.Earthquake Source Mechanics[C].Washington DC:AGU,1986.259-267.
[2]Mc Garr A.On relating apparent stress to the stress causing earthquake fault slip[J].J GeophysRes,1999,104:3 003-3 011.
[3]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.
[4]黄显良,刘东旺,沈小七,等.华东地区视应力场的研究[J].地震地磁观测与研究,2005,26(6):29-32.
[5]陈宇卫,张军,庆梅,等.“霍山地震窗”小震序列运动学参数时变特征研究[J].地震,2007,27(1):26-32.
[6]曹凤娟,尹涛,马丽.岫岩MS5.4地震前后视应力时空变化特征[J].东北地震研究,2005,21(1):14-19.
[7]李清河,黄耘,张元生,等.郯庐断裂带中南段速度结构特点[J].国际地震动态,2008,30(11):110-110.
[8]张毅,翟洪涛,顾春雷,等.郯庐断裂带中南段重磁综合剖面探测研究[J].国际地震动态,2011,387(3):10-11.
[9]Atkinson G M,Mereu R F.The shape of ground motion attenuation curves in southeastern Canada[J].BSSA,1992,82:2 014-2 031.
[10]黄玉龙,郑斯华,刘杰.广东地区地震动衰减和场地响应的研究[J].地球物理学报,2003,46(1):54-61.
[11]沈小七,刘杰,陈宇卫,等.安徽地区地震波衰减、场地响应及震源新参数的测定[J].地震地磁观测与研究,2005,26(3):1-10.
[12]郑先进,刘东旺,沈小七,等.安徽地区尾波Qc值特征研究[J].华北地震科学,2011,29(3):8-12.
[13]Andrews D J.Objective determination of source parameters and similarity of earthquakes of diferentsize[A].In:Das S,Boatwright J,Scholz C H.Earthquake Source Mechanics[C].Washington DC:AGU,1986.259-267.
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