2011年3月10日云南盈江5.8级地震序列研究
|
摘要
对2011年3月10日云南盈江5.8级地震序列作跟踪分析,提出了适合该地震序列趋势判断的部分方法。在该序列M≥4.8地震的几个子序列中,前震h值均小于1,较准确地判定了地震趋势;在前震和余震序列中b值没有出现前震序列低余震序列高的现象,因而用b值对该序列的判断是失败的;大盈江断裂上距离不远在类型相同的地震第1天的衰减方式有相似之处,可以为快速判定地震类型提供依据;本次5.8级地震是大盈江断裂在北北东向的主压应力作用下产生左旋走滑错动的结果,该序列3.6级以上地震的震源机制解显示主震发生后小震P、T轴出现了快速变化,从而为地震类型的判定提供了参考依据;主震发生后余震震中分布出现了北西向的共轭条带分布,这可能意示着主震发生后在原震源区发生更大地震的可能性较小。
We tried the h-value and b-value to trace the MS5.8 Yingjiang earthquake sequence and found that:(1)h-value after the Yingjiang MS4.8 earthquake on January 2 was 0.6,and the one after the MS4.8 earthquake on February 1 was 0.8.Both were less than 1.So we concluded that the two earthquakes were foreshocks and there would be a larger earthquake.The MS5.8 earthquake occurring on Mar.10 proved our judgment right.(2)b-value after the MS4.8 Yingjiang earthquake on January 2 was 0.77,and the one after the MS4.8 earthquake on February 1 was 0.82,according to these two high b-values we concluded that there would be no larger earthquakes anymore and we failed.Comparing the MS5.1 Yingjiang earthquake sequence on Mar.21,2008 with the MS5.8 earthquake sequence on Mar.10,we found that the earthquakes occurred closely on the Dayingjiang Fault showed the same characters of energy attenuation in the first day of the main shock.This regularity is helpful for the fast determination of the earthquake pattern.The MS5.8 earthquake resulted from the left-lateral,strike-slip faulting of the Dayingjiang Fault.Calculating the focal mechanisms of thirteen M≥3.6 events of the sequence,we found that P-axis and T-axis greatly changed.This regularity is also helpful for pattern determination.The epicenters of the aftershocks distributed conjugately in North-West direction,which means that the probability of another larger earthquake in the source region was small.
We tried the h-value and b-value to trace the MS5.8 Yingjiang earthquake sequence and found that:(1)h-value after the Yingjiang MS4.8 earthquake on January 2 was 0.6,and the one after the MS4.8 earthquake on February 1 was 0.8.Both were less than 1.So we concluded that the two earthquakes were foreshocks and there would be a larger earthquake.The MS5.8 earthquake occurring on Mar.10 proved our judgment right.(2)b-value after the MS4.8 Yingjiang earthquake on January 2 was 0.77,and the one after the MS4.8 earthquake on February 1 was 0.82,according to these two high b-values we concluded that there would be no larger earthquakes anymore and we failed.Comparing the MS5.1 Yingjiang earthquake sequence on Mar.21,2008 with the MS5.8 earthquake sequence on Mar.10,we found that the earthquakes occurred closely on the Dayingjiang Fault showed the same characters of energy attenuation in the first day of the main shock.This regularity is helpful for the fast determination of the earthquake pattern.The MS5.8 earthquake resulted from the left-lateral,strike-slip faulting of the Dayingjiang Fault.Calculating the focal mechanisms of thirteen M≥3.6 events of the sequence,we found that P-axis and T-axis greatly changed.This regularity is also helpful for pattern determination.The epicenters of the aftershocks distributed conjugately in North-West direction,which means that the probability of another larger earthquake in the source region was small.
引文
陈立德.1988.1970年1月5日云南省通海7.7级地震[M]//中国震例(1966—1975).张肇诚,罗兰格,李海华,等.1988.北京:地震出版社.
陈颙.1978.用震源机制一致性作为描述地震活动性的新参数[J].地球物理学报,21(2):142-159.
付虹,邬成栋.2008.川滇地区7级大震衰减特征及其在汶川地震中应用[J].地震研究,31(增刊),430-435.
付虹,王绍晋,龙晓帆,等.2009.宁洱地震序列的震源机制解分析[J].地震研究,32(3),253-257.
傅征祥.1982.强余震活动的持续时间[J].地震学报,4(4):389-394.
黄媛,吴建平,张天中,等.2008.汶川8.0级打地震及其余震序列重新定位研究[J].中国科学(D辑),38(10),1242-1249.
阚荣举,韩源.1992.云南遮放至马龙地学断面[M].北京:地震出版社.
梁尚鸿,李幼铭,束沛镒,等.1984.利用区域地震台网P、S振幅比资料测定小震震源参数[J].地球物理学报,27(3):249-257.
刘杰,郑斯华,康英,等.2004.利用P波和S波的初动和振幅比计算中小地震的震源机制解[J].地震,24(1):19-26.
刘正荣,孔绍麟.1986.根据地震频度衰减与地震预报[J].地震研究,9(1):6-8.
陆远忠,陈章立.1985.地震预报的地震学方法[M].北京:地震出版社.
毛玉平,韩新民.2003.云南地区强震(M≥6)研究[M].昆明:云南科技出版社.
朱传镇,王琳瑛.1989.震群信息熵异常与地震预[C]//地震预报方法实用化研究文集:地震学专辑.北京:学术书刊出版社,229-242.
Kisslinger C,Bowman J R,Koch K.1981.Procedures for computing focal mechan is MSfrom local(SV/P)z data[J].BSSA,71(6):1719-1729.
Klein F W.1978.Hypocenter location program HYPOINVERSE Part I:Users guide to versions1,2,3and4[J].U S Geol Surv Open-File Rept,78-694.
Snoke J A,Munsey J W,Teague A G,et al.1984.A program for focal mechanism determination by combined use of polarity and SV-P amplitude ratio data[J].Earthquake Notes,55(3):15-22.
Waldhauser F,Ellsworth W L.2000.A double-difference earthquake lo-cation algorithm:method and appficafon to the Northern Hayward Fault,California[J].BSSA,90(6):1353-1368.
陈颙.1978.用震源机制一致性作为描述地震活动性的新参数[J].地球物理学报,21(2):142-159.
付虹,邬成栋.2008.川滇地区7级大震衰减特征及其在汶川地震中应用[J].地震研究,31(增刊),430-435.
付虹,王绍晋,龙晓帆,等.2009.宁洱地震序列的震源机制解分析[J].地震研究,32(3),253-257.
傅征祥.1982.强余震活动的持续时间[J].地震学报,4(4):389-394.
黄媛,吴建平,张天中,等.2008.汶川8.0级打地震及其余震序列重新定位研究[J].中国科学(D辑),38(10),1242-1249.
阚荣举,韩源.1992.云南遮放至马龙地学断面[M].北京:地震出版社.
梁尚鸿,李幼铭,束沛镒,等.1984.利用区域地震台网P、S振幅比资料测定小震震源参数[J].地球物理学报,27(3):249-257.
刘杰,郑斯华,康英,等.2004.利用P波和S波的初动和振幅比计算中小地震的震源机制解[J].地震,24(1):19-26.
刘正荣,孔绍麟.1986.根据地震频度衰减与地震预报[J].地震研究,9(1):6-8.
陆远忠,陈章立.1985.地震预报的地震学方法[M].北京:地震出版社.
毛玉平,韩新民.2003.云南地区强震(M≥6)研究[M].昆明:云南科技出版社.
朱传镇,王琳瑛.1989.震群信息熵异常与地震预[C]//地震预报方法实用化研究文集:地震学专辑.北京:学术书刊出版社,229-242.
Kisslinger C,Bowman J R,Koch K.1981.Procedures for computing focal mechan is MSfrom local(SV/P)z data[J].BSSA,71(6):1719-1729.
Klein F W.1978.Hypocenter location program HYPOINVERSE Part I:Users guide to versions1,2,3and4[J].U S Geol Surv Open-File Rept,78-694.
Snoke J A,Munsey J W,Teague A G,et al.1984.A program for focal mechanism determination by combined use of polarity and SV-P amplitude ratio data[J].Earthquake Notes,55(3):15-22.
Waldhauser F,Ellsworth W L.2000.A double-difference earthquake lo-cation algorithm:method and appficafon to the Northern Hayward Fault,California[J].BSSA,90(6):1353-1368.