2018年印尼帕卢M_W7.5地震——一次超剪切破裂事件
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摘要
利用反投影方法,使用日本密集台网Hi-net远场垂直分量568条P波资料对2018年9月28日印尼帕卢M_W7.5地震震源破裂过程进行成像,结果显示此次地震的能量释放比较集中,主要集中在10～20s之间.破裂有两个集中区,破裂峰值分别位于12s和19s,最大能量释放区域位于震中南侧约0～50km内,另一破裂集中区覆盖了帕卢市及周边区域.破裂主要向南侧延展,破裂总长度至少100km,平均破裂速度约4.1km·s~(-1),属于一次超剪切破裂事件.
In this study,we used the vertical components of 568 teleseismic P-wave records from the Hi-net array and back-project method to image the rupturing process of the M_W7.5 Palu,Indonesia,earthquake on September 28,2018.The results show that the rupture initiated from the epicenter located by USGS,then propagated to the south along a nearly NS-trending fault and finally ended at least 100 km to the start point.The most of the earthquake energy was released during the first 10～20 safter the initiation of the event.There are two main rupture zones,corresponding to two peak ruptures at 12 sand 19 safter the mainshock,respectively.The maximum energy release area is located approximately 0～50 km south of the epicenter,and the other one covers the city of Palu and its surrounding areas.The estimated average rupture velocity is about 4.1 km·s~(-1) which is larger than the S wave velocity,indicating that the earthquake is a supershear rupturing event.
In this study,we used the vertical components of 568 teleseismic P-wave records from the Hi-net array and back-project method to image the rupturing process of the M_W7.5 Palu,Indonesia,earthquake on September 28,2018.The results show that the rupture initiated from the epicenter located by USGS,then propagated to the south along a nearly NS-trending fault and finally ended at least 100 km to the start point.The most of the earthquake energy was released during the first 10～20 safter the initiation of the event.There are two main rupture zones,corresponding to two peak ruptures at 12 sand 19 safter the mainshock,respectively.The maximum energy release area is located approximately 0～50 km south of the epicenter,and the other one covers the city of Palu and its surrounding areas.The estimated average rupture velocity is about 4.1 km·s~(-1) which is larger than the S wave velocity,indicating that the earthquake is a supershear rupturing event.
引文
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Bouchon M,Bouin M P,Karabulut H,et al.2001.How fast is rupture during an earthquake?New insights from the 1999Turkey earthquake.Geophysical Research Letters,28(14):2723-2726.
Broberg K B.1996.How fast can a crack go?Materials Science,32(1):80-86.
Das S.2007.The need to study speed.Science,317(5840):905-906.
Dunham E M,Favreau P,Carlson J M.2003.A supershear transition mechanism for cracks.Science,299(5612):1557-1559.
He P,Wang Q,Ding K H,et al.2016.Coseismic and postseismic slip ruptures for 2015 MW6.4Pishan earthquake constrained by static GPS solutions.Geodesy and Geodynamics,7(5):323-328.
Heaton T H.1990.Evidence for and implications of self-healing pulses of slip in earthquake rupture.Physics of the Earth and Planetary Interiors,64(1):1-20.
Institute of Geophysics,China Earthquake Administration.2018.http:∥www.eq-igl.ac.cn.
Ishii M,Shearer P M,Houston H,et al.2005.Extent,duration and speed of the 2004Sumatra-Andaman earthquake imaged by the Hi-Net array.Nature,435(7044):933-936.
Ishii M.2011.High-frequency rupture properties of the MW9.0off the Pacific coast of Tohoku Earthquake.Earth,Planets and Space,63:609-614.
Kikuchi M,Kanamori H.1991.Inversion of complex body wavesIII.Bulletin of the Seismological Society of America,81(6):2335-2350.
Kikuchi M,Kanamori H,Satake K.1993.Source complexity of the1988Armenian earthquake:evidence for a slow after-slip event.Journal of Geophysical Research:Solid Earth,98(B9):15797-15808.
Li Q,Tan K,Wang D Z,et al.2018.Joint inversion of GNSS and teleseismic data for the rupture process of the 2017 MW6.5Jiuzhaigou,China,earthquake.Journal of Seismology,22(3):805-814,doi:10.1007/s10950-018-9733-1.
Liu Z P,Song C,Meng L S,et al.2017.Utilizing a 3Dglobal P-wave tomography model to improve backprojection imaging:a case study of the 2015 Nepal earthquake.Bulletin of the Seismological Society of America,107(5):2459-2466,doi:10.1785/0120170091.
Okuwaki R,Yagi Y,Shimizu K.2018.Rupture process of the 2018Palu,Indonesia,earthquake.https:∥github.com/rokuwaki/2018PaluIndonesia.
Robinson D P,Brough C,Das S.2006.The MW7.8,2001Kunlunshan earthquake:Extreme rupture speed variability and effect of fault geometry.Journal of Geophysical Research:Solid Earth,111(B8):B08303,doi:10.1029/2005JB004137.
Tan H B,Wu G J,Xuan S B,et al.2015.Wenchuan MS8.0earthquake coseismic slip distribution inversion.Geodesy and Geodynamics,6(3):173-179.
Tan K,Zhang C H,Zhao B,et al.2017.Multiplicity of solutions to geophysical inversion reflected by rupture slip distribution of the2015Nepal earthquake.Geodesy and Geodynamics,8(1):59-96.
USGS.(2018-09-28).M7.5-70km N of Palu,Indonesia.https:∥earthquake.usgs.gov/earthquakes/eventpage/us1000h3p4/finite-fault.
Walker K T,Shearer P M.2009.Illuminating the near-sonic rupture velocities of the intracontinental Kokoxili MW 7.8and Denali fault MW7.9strike-slip earthquakes with global P wave back projection imaging.Journal of Geophysical Research:Solid Earth,114(B2):B02304,doi:10.1029/2008JB005738.
Wang D,Kawakatsu H,Mori J,et al.2016a.Backprojection analyses from four regional arrays for rupture over a curved dipping fault:The MW7.7 24September 2013Pakistan earthquake.Journal of Geophysical Research:Solid Earth,121(3):1948-1961.
Wang D,Mori J,Koketsu K.2016b.Fast rupture propagation for large strike-slip earthquakes.Earth and Planetary Science Letters,440:115-126.
Wang H Y.2010.Prediction of acceleration field of the 14 April2010 Yushu earthquake.Chinese Journal of Geophysics(in Chinese),53(10):2345-2354,doi:10.3969/j.issn.0001-5733.2010.10.008.
Wang Q,Qiao X J,Lan Q G,et al.2011.Rupture of deep faults in the 2008Wenchuan earthquake and uplift of the Longmen Shan.Nature Geoscience,4(9):634-640.
Wei Y G,Zhang S.2017.Design and location selection of Hi-net.Recent Developments in World Seismology(in Chinese),(2):16-23.
Wessel P,Smith W H F.1995.New,improved version of generic mapping tools released.Eos,Transactions American Geophysical Union,79(47):579.
Xu C J,Gong Z,Niu J M.2016.Recent developments in seismological geodesy.Geodesy and Geodynamics,7(3):157-164.
Xu Y,Koper K D,Sufri O,et al.2013.Rupture imaging of the MW7.9 12May 2008Wenchuan earthquake from back projection of teleseismic P waves.Geochemistry,Geophysics,Geosystems,10(4):Q04006,doi:10.1029/2008GC002335.
Yokota Y,Koketsu K,Fujii Y,et al.2011.Joint inversion of strong motion,teleseismic,geodetic,and tsunami datasets for the rupture process of the 2011 Tohoku earthquake.Geophysical Research Letters,38(7):L00G21,doi:10.1029/2011GL050098.
Yuan J,Zhu S B.2017.Numerical simulation of seismic supershear rupture process facilitated by a fault stepover.Chinese Journal of Geophysics(in Chinese),60(1):212-224,doi:10.6038/cjg20170118.
Zhang H,Ge Z X.2012.Rupture Imaging of the 2010 MW8.8great Chilean earthquake using relative back-projection method.Acta Scientiarum Naturalium Universitatis Pekinensis(in Chinese),48(4):583-588.
Zhang L F,Fatchurochman I,Liao W L,et al.2013.Source rupture process inversion of the 2013 Lushan earthquake,China.Geodesy and Geodynamics,4(2):16-21.
Zhang L F,Li J G,Liao W L,et al.2016.Source rupture process of the 2015Gorkha,Nepal MW7.9earthquake and its tectonic implications.Geodesy and Geodynamics,7(2):124-131.
Zhang R P.2014.Analysis of the Wenchuan earthquake source process[Master′s thesis](in Chinese).Chengdu:Chengdu University of Technology.
Zhu S B,Yuan J,Miao M.2017.Dynamic mechanisms for supershear rupture processes of the Yushu earthquake(MS=7.1).Chinese Journal of Geophysics(in Chinese),60(10):3832-3843,doi:10.6038/cjg20171013.
王海云.2010.2010年4月14日玉树MS7.1地震加速度场预测.地球物理学报,53(10):2345-2354,doi:10.3969/j.issn.0001-5733.2010.10.008.
隗永刚,张爽.2017.日本Hi-net台网的台站选址与设计.国际地震动态,(2):16-23.
袁杰,朱守彪.2017.断层阶区对产生超剪切地震破裂的促进作用.地球物理学报,60(1):212-224,doi:10.6038/cjg20170118.
张浩,盖增喜.2012.利用相对反投影方法对2010年MW8.8级智利地震破裂过程成像.北京大学学报(自然科学版),48(4):583-588.
张人鹏.2014.汶川地震震源过程分析[硕士论文].成都:成都理工大学
中国地震局地质研究所.2018.http:∥www.eq-igl.ac.cn.
朱守彪,袁杰,缪淼.2017.青海玉树地震(MS=7.1)产生超剪切破裂过程的动力学机制研究.地球物理学报,60(10):3832-3843,doi:10.6038/cjg20171013.
Bouchon M,Bouin M P,Karabulut H,et al.2001.How fast is rupture during an earthquake?New insights from the 1999Turkey earthquake.Geophysical Research Letters,28(14):2723-2726.
Broberg K B.1996.How fast can a crack go?Materials Science,32(1):80-86.
Das S.2007.The need to study speed.Science,317(5840):905-906.
Dunham E M,Favreau P,Carlson J M.2003.A supershear transition mechanism for cracks.Science,299(5612):1557-1559.
He P,Wang Q,Ding K H,et al.2016.Coseismic and postseismic slip ruptures for 2015 MW6.4Pishan earthquake constrained by static GPS solutions.Geodesy and Geodynamics,7(5):323-328.
Heaton T H.1990.Evidence for and implications of self-healing pulses of slip in earthquake rupture.Physics of the Earth and Planetary Interiors,64(1):1-20.
Institute of Geophysics,China Earthquake Administration.2018.http:∥www.eq-igl.ac.cn.
Ishii M,Shearer P M,Houston H,et al.2005.Extent,duration and speed of the 2004Sumatra-Andaman earthquake imaged by the Hi-Net array.Nature,435(7044):933-936.
Ishii M.2011.High-frequency rupture properties of the MW9.0off the Pacific coast of Tohoku Earthquake.Earth,Planets and Space,63:609-614.
Kikuchi M,Kanamori H.1991.Inversion of complex body wavesIII.Bulletin of the Seismological Society of America,81(6):2335-2350.
Kikuchi M,Kanamori H,Satake K.1993.Source complexity of the1988Armenian earthquake:evidence for a slow after-slip event.Journal of Geophysical Research:Solid Earth,98(B9):15797-15808.
Li Q,Tan K,Wang D Z,et al.2018.Joint inversion of GNSS and teleseismic data for the rupture process of the 2017 MW6.5Jiuzhaigou,China,earthquake.Journal of Seismology,22(3):805-814,doi:10.1007/s10950-018-9733-1.
Liu Z P,Song C,Meng L S,et al.2017.Utilizing a 3Dglobal P-wave tomography model to improve backprojection imaging:a case study of the 2015 Nepal earthquake.Bulletin of the Seismological Society of America,107(5):2459-2466,doi:10.1785/0120170091.
Okuwaki R,Yagi Y,Shimizu K.2018.Rupture process of the 2018Palu,Indonesia,earthquake.https:∥github.com/rokuwaki/2018PaluIndonesia.
Robinson D P,Brough C,Das S.2006.The MW7.8,2001Kunlunshan earthquake:Extreme rupture speed variability and effect of fault geometry.Journal of Geophysical Research:Solid Earth,111(B8):B08303,doi:10.1029/2005JB004137.
Tan H B,Wu G J,Xuan S B,et al.2015.Wenchuan MS8.0earthquake coseismic slip distribution inversion.Geodesy and Geodynamics,6(3):173-179.
Tan K,Zhang C H,Zhao B,et al.2017.Multiplicity of solutions to geophysical inversion reflected by rupture slip distribution of the2015Nepal earthquake.Geodesy and Geodynamics,8(1):59-96.
USGS.(2018-09-28).M7.5-70km N of Palu,Indonesia.https:∥earthquake.usgs.gov/earthquakes/eventpage/us1000h3p4/finite-fault.
Walker K T,Shearer P M.2009.Illuminating the near-sonic rupture velocities of the intracontinental Kokoxili MW 7.8and Denali fault MW7.9strike-slip earthquakes with global P wave back projection imaging.Journal of Geophysical Research:Solid Earth,114(B2):B02304,doi:10.1029/2008JB005738.
Wang D,Kawakatsu H,Mori J,et al.2016a.Backprojection analyses from four regional arrays for rupture over a curved dipping fault:The MW7.7 24September 2013Pakistan earthquake.Journal of Geophysical Research:Solid Earth,121(3):1948-1961.
Wang D,Mori J,Koketsu K.2016b.Fast rupture propagation for large strike-slip earthquakes.Earth and Planetary Science Letters,440:115-126.
Wang H Y.2010.Prediction of acceleration field of the 14 April2010 Yushu earthquake.Chinese Journal of Geophysics(in Chinese),53(10):2345-2354,doi:10.3969/j.issn.0001-5733.2010.10.008.
Wang Q,Qiao X J,Lan Q G,et al.2011.Rupture of deep faults in the 2008Wenchuan earthquake and uplift of the Longmen Shan.Nature Geoscience,4(9):634-640.
Wei Y G,Zhang S.2017.Design and location selection of Hi-net.Recent Developments in World Seismology(in Chinese),(2):16-23.
Wessel P,Smith W H F.1995.New,improved version of generic mapping tools released.Eos,Transactions American Geophysical Union,79(47):579.
Xu C J,Gong Z,Niu J M.2016.Recent developments in seismological geodesy.Geodesy and Geodynamics,7(3):157-164.
Xu Y,Koper K D,Sufri O,et al.2013.Rupture imaging of the MW7.9 12May 2008Wenchuan earthquake from back projection of teleseismic P waves.Geochemistry,Geophysics,Geosystems,10(4):Q04006,doi:10.1029/2008GC002335.
Yokota Y,Koketsu K,Fujii Y,et al.2011.Joint inversion of strong motion,teleseismic,geodetic,and tsunami datasets for the rupture process of the 2011 Tohoku earthquake.Geophysical Research Letters,38(7):L00G21,doi:10.1029/2011GL050098.
Yuan J,Zhu S B.2017.Numerical simulation of seismic supershear rupture process facilitated by a fault stepover.Chinese Journal of Geophysics(in Chinese),60(1):212-224,doi:10.6038/cjg20170118.
Zhang H,Ge Z X.2012.Rupture Imaging of the 2010 MW8.8great Chilean earthquake using relative back-projection method.Acta Scientiarum Naturalium Universitatis Pekinensis(in Chinese),48(4):583-588.
Zhang L F,Fatchurochman I,Liao W L,et al.2013.Source rupture process inversion of the 2013 Lushan earthquake,China.Geodesy and Geodynamics,4(2):16-21.
Zhang L F,Li J G,Liao W L,et al.2016.Source rupture process of the 2015Gorkha,Nepal MW7.9earthquake and its tectonic implications.Geodesy and Geodynamics,7(2):124-131.
Zhang R P.2014.Analysis of the Wenchuan earthquake source process[Master′s thesis](in Chinese).Chengdu:Chengdu University of Technology.
Zhu S B,Yuan J,Miao M.2017.Dynamic mechanisms for supershear rupture processes of the Yushu earthquake(MS=7.1).Chinese Journal of Geophysics(in Chinese),60(10):3832-3843,doi:10.6038/cjg20171013.
王海云.2010.2010年4月14日玉树MS7.1地震加速度场预测.地球物理学报,53(10):2345-2354,doi:10.3969/j.issn.0001-5733.2010.10.008.
隗永刚,张爽.2017.日本Hi-net台网的台站选址与设计.国际地震动态,(2):16-23.
袁杰,朱守彪.2017.断层阶区对产生超剪切地震破裂的促进作用.地球物理学报,60(1):212-224,doi:10.6038/cjg20170118.
张浩,盖增喜.2012.利用相对反投影方法对2010年MW8.8级智利地震破裂过程成像.北京大学学报(自然科学版),48(4):583-588.
张人鹏.2014.汶川地震震源过程分析[硕士论文].成都:成都理工大学
中国地震局地质研究所.2018.http:∥www.eq-igl.ac.cn.
朱守彪,袁杰,缪淼.2017.青海玉树地震(MS=7.1)产生超剪切破裂过程的动力学机制研究.地球物理学报,60(10):3832-3843,doi:10.6038/cjg20171013.