用Pn-Pg走时差计算内蒙古地区地震震源深度
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摘要
震源深度是地震学研究的关键参数,也是难以准确测定的参数之一。由于Pn和Pg震相的路径特征,其走时差对震源深度的变化较敏感,Pn和Pg震相是地震台网观测报告中数量较丰富且精度较高的震相数据,因此Pn-Pg方法为震源深度测定提供了简便且可行的方式。本文讨论了使用Pn-Pg走时差测定震源深度的实现方式,使用模拟数据评估了该方法的误差,结果表明,震相到时误差在一定范围时,此方法可以给出较可靠的深度结果。使用Pn和Pg走时差计算了内蒙古地区地震的震源深度,重新测定的深度频次分布更加合理,区域差异也比较明显,东部和西部的震源深度较深,中部地区震源深度较浅。
The focal depth is a key parameter for seismology and one of the parameters difficult to be accurately measured.Because Pn-Pg travel time difference is sensitive to focal depth and the two phases are rich in seismic observation report with high precision,Pn-Pg method provides a simple and feasible way for focal depth determination.This paper discusses the realization of Pg-Pn method to determine focal depth.Using simulated data to evaluate the method,the results show that when phase error is in a certain range,this method can give reliable results.The focal depths of earthquakes in Inner Mongolia area were determined using this method.The results show that the remeasured depth frequency distribution is more reasonable and the regional difference is obvious.The focal depth in the east and west is deeper and the focal depth in the central region is relatively shallow.
The focal depth is a key parameter for seismology and one of the parameters difficult to be accurately measured.Because Pn-Pg travel time difference is sensitive to focal depth and the two phases are rich in seismic observation report with high precision,Pn-Pg method provides a simple and feasible way for focal depth determination.This paper discusses the realization of Pg-Pn method to determine focal depth.Using simulated data to evaluate the method,the results show that when phase error is in a certain range,this method can give reliable results.The focal depths of earthquakes in Inner Mongolia area were determined using this method.The results show that the remeasured depth frequency distribution is more reasonable and the regional difference is obvious.The focal depth in the east and west is deeper and the focal depth in the central region is relatively shallow.
引文
[1]高原,周蕙兰,郑斯华,等.测定震源深度的意义的初步讨论[J].中国地震,1997,13(4):321-329.
[2] Galdeano C S,Casado C L,Delgado A,et al.Shallow seismicity and active faults in the Betic Cordillera.A preliminary approach to seismic sources associated with specific faults[J].Tectonophysics,1995,248(3):293-302.
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[4] Wu C,Takeo M.An intermediate deep earthquake rupturing on a dip-bending fault:Waveform analysis of the 2003Miyagi ken Oki earthquake[J].Geophys Res Lett,2004,312(24):357-370.
[5] Stein S,Wiens D A.Depth determination for shallow teleseismic earthquakes:Methods and results[J].Rev Geophys,1986,24(4):806-832.
[6]高原,吴忠良.1993年11月13日堪察加大地震的破裂过程及其构造意义[J].1995,38(1):55-63.
[7]吴忠良,黄静,周公威.震源深度与矩心深度的分布特征及其与震源机制类型之间的关系[J].中国地震,2002,18(4):337-345.
[8]郑斯华.青藏高原地震的震源深度及其构造意义[J].中国地震,1995,(2):99-106.
[9] Satyabala S P.Coseismic ground deformation due to an intrapiate earthquake using synthetic aperture radar interferometry:The MW6.1Killari.India.earthquake of 29September 1993[J].J Geophys Res,2006,111(B2):301-316.
[10]罗艳,曾祥方,倪四道.震源深度测定方法研究进展[J].地球物理学进展,2013,28(5):2 309-2 321
[11]王登伟.利用直达P波测定地方震震源深度的探讨[J].地震地磁观测与研究,2010,31(5):45-48.
[12]高立新,刘芳,赵蒙生,等.用sPn震相计算震源深度的初步分析与应用[J].西北地震学报,2007,29(3):213-217.
[13]崇加军,倪四道,曾祥方.sPL,一个近距离确定震源深度的震相[J].地球物理报,2010,53(11):2 620-2 630.
[14] Mori J.Estimates of velocity structure and source depth using multiple P waves from aftershocks of the 1987Elmore Ranch and Superstition Hills,California,earthquakes[J].Bull Seism Soc Am,1991,81(2):508-523.
[15] Roger W.Greensfelder.The Pg-Pn method of determining depth of focus with applications to Nevada earthquakes[J].Bull Seism Soc Am,1965,55(2):391-403.
[16]朱元清,石耀林,李平.一种确定震源深度的新方法[J].地震地磁观测与研究,1990,11(2):4-12.
[17]朱元清,夏俊平,李平.确定震源深度的PTD方法及其应用[J].地震地磁观测与研究,1997,18(3):21-29.
[18]王新岭,张国民,马宏生,等.用PTD方法测定巴林左旗5.9级地震震源深度[J].地震,2004,24(4):51-56.
[19]宋秀青,缪发军,刘双庆,等.2014年新疆于田MS7.3地震序列的震源深度测定[J].中国地震,2014,30(2):198-207.
[20]倪红玉,杨勋普,汪小厉,等.基于PTD方法测定2014年金寨ML3.9震群的震源深度[J].华北地震科学,2015,33(3):26-30.
[21]殷伟伟,陈存田,刘林飞,等.PTD方法在山西震源深度测定中的应用研究[J].山西地震,2016(3):33-36.
[22]陈浩,曾文敬,肖孟仁,等.赣南地区地震震源深度计算方法初探[J].高原地震,2016,28(2):30-33.
[23]刘双庆,薛艳,蔡宏雷,等.利用重测定的震源深度特征探讨2013年吉林前郭5.8级震群发震因素[J].地震研究,2015,38(2):211-220.
[24]万永革.地震学导论[M].科学出版社,2016.
[25] Laske G,Masters G,Ma Z,et al.CRUST1.0:An Updated Global Model of Earth's Crust[C]∥EGU General Assembly Conference.EGU General Assembly Conference Abstracts,2012.
[26] Laske G,Masters G.A global digital map of sediment thickness[J].EOS Transactions,1997,78,F483.
[2] Galdeano C S,Casado C L,Delgado A,et al.Shallow seismicity and active faults in the Betic Cordillera.A preliminary approach to seismic sources associated with specific faults[J].Tectonophysics,1995,248(3):293-302.
[3]张国民,汪素云,李丽,等.中国大陆地震震源深度及其构造含义[J].科学通报,2002,47(9):663-668.
[4] Wu C,Takeo M.An intermediate deep earthquake rupturing on a dip-bending fault:Waveform analysis of the 2003Miyagi ken Oki earthquake[J].Geophys Res Lett,2004,312(24):357-370.
[5] Stein S,Wiens D A.Depth determination for shallow teleseismic earthquakes:Methods and results[J].Rev Geophys,1986,24(4):806-832.
[6]高原,吴忠良.1993年11月13日堪察加大地震的破裂过程及其构造意义[J].1995,38(1):55-63.
[7]吴忠良,黄静,周公威.震源深度与矩心深度的分布特征及其与震源机制类型之间的关系[J].中国地震,2002,18(4):337-345.
[8]郑斯华.青藏高原地震的震源深度及其构造意义[J].中国地震,1995,(2):99-106.
[9] Satyabala S P.Coseismic ground deformation due to an intrapiate earthquake using synthetic aperture radar interferometry:The MW6.1Killari.India.earthquake of 29September 1993[J].J Geophys Res,2006,111(B2):301-316.
[10]罗艳,曾祥方,倪四道.震源深度测定方法研究进展[J].地球物理学进展,2013,28(5):2 309-2 321
[11]王登伟.利用直达P波测定地方震震源深度的探讨[J].地震地磁观测与研究,2010,31(5):45-48.
[12]高立新,刘芳,赵蒙生,等.用sPn震相计算震源深度的初步分析与应用[J].西北地震学报,2007,29(3):213-217.
[13]崇加军,倪四道,曾祥方.sPL,一个近距离确定震源深度的震相[J].地球物理报,2010,53(11):2 620-2 630.
[14] Mori J.Estimates of velocity structure and source depth using multiple P waves from aftershocks of the 1987Elmore Ranch and Superstition Hills,California,earthquakes[J].Bull Seism Soc Am,1991,81(2):508-523.
[15] Roger W.Greensfelder.The Pg-Pn method of determining depth of focus with applications to Nevada earthquakes[J].Bull Seism Soc Am,1965,55(2):391-403.
[16]朱元清,石耀林,李平.一种确定震源深度的新方法[J].地震地磁观测与研究,1990,11(2):4-12.
[17]朱元清,夏俊平,李平.确定震源深度的PTD方法及其应用[J].地震地磁观测与研究,1997,18(3):21-29.
[18]王新岭,张国民,马宏生,等.用PTD方法测定巴林左旗5.9级地震震源深度[J].地震,2004,24(4):51-56.
[19]宋秀青,缪发军,刘双庆,等.2014年新疆于田MS7.3地震序列的震源深度测定[J].中国地震,2014,30(2):198-207.
[20]倪红玉,杨勋普,汪小厉,等.基于PTD方法测定2014年金寨ML3.9震群的震源深度[J].华北地震科学,2015,33(3):26-30.
[21]殷伟伟,陈存田,刘林飞,等.PTD方法在山西震源深度测定中的应用研究[J].山西地震,2016(3):33-36.
[22]陈浩,曾文敬,肖孟仁,等.赣南地区地震震源深度计算方法初探[J].高原地震,2016,28(2):30-33.
[23]刘双庆,薛艳,蔡宏雷,等.利用重测定的震源深度特征探讨2013年吉林前郭5.8级震群发震因素[J].地震研究,2015,38(2):211-220.
[24]万永革.地震学导论[M].科学出版社,2016.
[25] Laske G,Masters G,Ma Z,et al.CRUST1.0:An Updated Global Model of Earth's Crust[C]∥EGU General Assembly Conference.EGU General Assembly Conference Abstracts,2012.
[26] Laske G,Masters G.A global digital map of sediment thickness[J].EOS Transactions,1997,78,F483.