2016年日本熊本地震破裂时空过程联合反演

蒋生淼, 易磊, 张旭, 温扬茂

蒋生淼, 易磊, 张旭, 温扬茂. 2018: 2016年日本熊本地震破裂时空过程联合反演. 地震学报, 40(1): 13-23. DOI: 10.11939/jass.20170097
引用本文: 蒋生淼, 易磊, 张旭, 温扬茂. 2018: 2016年日本熊本地震破裂时空过程联合反演. 地震学报, 40(1): 13-23. DOI: 10.11939/jass.20170097
Jiang Shengmiao, Yi Lei, Zhang Xu, Wen Yangmao. 2018: Joint inversion of teleseismic and co-seismic InSAR data for the rupture process of the 2016 Kumamoto earthquake in Japan. Acta Seismologica Sinica, 40(1): 13-23. DOI: 10.11939/jass.20170097
Citation: Jiang Shengmiao, Yi Lei, Zhang Xu, Wen Yangmao. 2018: Joint inversion of teleseismic and co-seismic InSAR data for the rupture process of the 2016 Kumamoto earthquake in Japan. Acta Seismologica Sinica, 40(1): 13-23. DOI: 10.11939/jass.20170097

2016年日本熊本地震破裂时空过程联合反演

详细信息
    通讯作者:

    蒋生淼: e-mail: jiangshengmiaob@163.com

  • 中图分类号: P315.3+3

Joint inversion of teleseismic and co-seismic InSAR data for the rupture process of the 2016 Kumamoto earthquake in Japan

  • 摘要: 为了深入认识2016年4月15日日本熊本地震破裂的复杂性,利用远场体波资料和同震InSAR资料联合反演了此次地震的震源破裂时空过程. 联合反演结果表明:熊本地震的震源破裂持续时间约为25 s,整个破裂过程释放的总标量矩为6.03×1019 N·m,对应于矩震级MW7.1;同震滑动主要集中分布于浅部,破裂以右旋走滑为主,但在沿倾向0—5 km范围内,破裂呈较强的正断特征;此次地震破裂的最大同震滑动量约为4.9 m,且最大同震位错区位于背离断层走向上、距离起始破裂点约5—10 km的区域;破裂前期(0—7 s),在倾向上向浅表发生破裂,在走向上向东北和西南两侧扩展;大约7 s后,破裂背离断层走向主要向东北方向扩展. 根据有限断层联合反演结果推测,此次熊本地震破裂可能出露至地表.
    Abstract: On April 15, 2016, a disastrous earthquake struck Kumamoto county in Japan. Aiming to further understand the complexity of the earthquake rupture in detail, we conduct a joint inversion of teleseismic waveforms and co-seismic InSAR data for the spatio-temporal rupture process of this earthquake. The results show that, the whole process lasted for about 25 s and released scalar moment up to 6.03×1019 N·m, corresponding to moment magnitude MW7.1. The major co-seismic slip distribution was centered in shallow region, and it was dominated by dextral strike. But the rupture had strong normal characteristics in the range of 0−5 km along the dip direction. The maximum co-seismic slip is about 4.9 m, and the major rupture patch was about 5−10 km away from the initial rupture point opposite to the strike direction. In the early stage (0−7 s), it ruptured toward to the shallow region along the dip direction, and ruptured bilaterally along strike direction; about 7 s later, it ruptured toward to the northeast opposite to the strike direction. The joint inversion results suggest that the Kumamoto earthquake may rupture to the earth surface.
  • 根据美国地质调查局地震信息中心(USGS,2016)测定,2016年4月15日16时25分(UTC)日本熊本县发生MW7.0强震,震中位于(32.791°N,130.754°E),震源深度为10 km. 主震前发生了3次MW≥5.5前震,主震后发生了一系列余震并动态触发了一次MW5.7强余震(Uchide et al,2016 Yoshida,2016),熊本强震序列造成了严重的地震灾害. 美国地质调查局发布的熊本地震强地面运动估算结果显示,极震区最大烈度约为IX度(USGS,2016). 此外,USGS(2016)的W-震相矩张量反演结果表明,此次强震发震断层对应的几何特征为走向224°,倾角66°,滑动角−152°,该次事件以右旋走滑为主,兼有正断分量.图1给出了熊本地震的区域构造及其破裂特征.

    对于此次熊本地震,已有一些研究人员利用远场地震波形资料(Yagi et al,2016 )和联合近场强地面运动数据(Hao et al,2017 )反演得到了此次事件的破裂时空过程结果. Fukahata和Hashimoto(2016)以及Himematsu和Furuya(2016)分别利用合成孔径雷达干涉成像(interferogram synthetic aperture radar,简写为InSAR)资料反演得到了此次事件对应的同震滑动分布特征. 但由于此次熊本地震的破裂过程较为复杂,不同反演结果间的显著差异性表明,单独利用地震波形数据或静态大地测量数据来反演地震破裂时空特征会存在不同程度的局限性. 鉴于此,本文拟利用远场体波和同震InSAR资料对此次熊本强震进行有限断层联合反演,更好地约束此次事件的破裂时空历史,以期深入认识复杂地质构造背景下熊本地震活动性的时空演化特征及其震害形成机理.

    图  1  熊本MW7.0地震区域构造及其破裂特征
    Figure  1.  Regional tectonic settings and rupture characteristics of the 2016 Kumamoto MW7.0 earthquake

    从美国地震学联合研究会(Incorporated Research Institutions for Seismology,简写为IRIS)数据中心提供的全球地震台网(Global Seismographic Network,简写为GSN)下载震中距处于30°—90°范围内的信噪比较好且方位覆盖较为均匀的46个台站(图2a)的远场宽频带垂直向波形记录,对波形资料进行0.02—0.1 Hz的带通滤波用于弱化长周期噪声以及三维复杂地球结构引起的短周期信号干扰. 对经过上述预处理的46个台站的波形资料,采用总长度为60 s的时间窗(P波初动前10 s,P波初动后50 s)截取波形资料用于后续破裂过程的反演. 基于AK135全球一维速度模型(Kennett et al,1995 ),采用反透射系数法(Wang,1999)来计算不同远场台站处对应的地震波传播路径效应(理论格林函数),并对合成的理论格林函数同样进行0.02—0.1 Hz的带通滤波.

    InSAR资料来源于2景哨兵一号(Sentinel-1)卫星2016年4月8日和2016年4月20日的合成孔径雷达(synthetic aperture radar,简写为SAR)影像资料. SAR卫星数据为干涉宽幅(Interferometric Wide Swath,简写为IWS)模式,由3个含若干猝发的子幅组成,幅宽为250 km. 为获取熊本地震的同震地表形变场,对资料进行基于二通法的差分干涉处理. 为保证方位向上的配准精度达到千分级像素,消除相邻猝发间可能出现的相位跳跃(Scheiber,Moreira,2000),我们在递进地形扫描方式干涉处理中,采用考虑地形影响的重采样技术和估计重叠猝发区相位差的谱分离方法(Farr et al,2000 ),利用欧洲航天局(European Space Agency,简写为ESA)提供的精密轨道数据和美国国家航空航天局(National Aeronautics and Space Administration,简写为NASA)提供的90 m分辨率的全球数字高程模型(shuttle radar topography mission digital elevation model,简写为SRTM DEM)数据去除地形相位的影响. 与此同时,为降低干涉相位的噪声水平、提高干涉图的信号质量,我们采用基于能量谱的局部自适应滤波和枝切法来解缠得到差分干涉相位(Goldstein et al,1988 ). 最终得到用于联合反演此次熊本地震的同震InSAR资料的覆盖区域如图2b所示.

    图  2  用于熊本地震破裂过程联合反演的远场体波台站分布(a)以及同震InSAR资料覆盖区域(b)
    红色星形表示主震震中位置。图(a)中蓝色三角形表示台站;图(b)中红色方框表示InSAR覆盖区域,黑色框表示图1中的展示区域,黑色圆圈表示主震发生后一个月内MW≥4.0余震的震中分布(USGS,2016)
    Figure  2.  Distribution of used teleseismic stations (a) and co-seismic InSAR coverage (b) for joint inversion of rupture process of Kumamoto earthquake
    The red star represents the mainshock epicenter. The blue triangles in Fig.(a) represent the stations. The red rectangular in Fig. (b) is the co-seismic coverage,the black rectangular delineates the region shown in Fig. 1,and black circles are the MW≥4.0 aftershocks within one month after the main shock (USGS,2016)

    根据前述USGS测定的熊本地震主震震源位置信息(32.791°N,130.754°E,10.0 km)以及W-震相矩张量反演结果中的断层几何特征(走向224°,倾角66°),本文构建90 km×35 km的初始有限断层模型用于破裂时空过程的反演,对应的子断层网格尺寸为5 km×5 km.

    本文采用基于地震波形资料和静态大地测量资料的有限断层破裂时空过程联合反演方法.该联合反演方法不需要预先给定子断层的震源时间函数形状(Chen,Xu,2000Xu et al,2002 张勇,2008张旭,2016),而是通过共轭梯度法(Ward,Barrientos,1986)来迭代反演子断层的震源时间函数,从而避免了由于给定的先验子断层震源时间函数不合适造成反演结果出现偏差;并且子断层在破裂过程中相对于平均滑动角允许存在±45°的滑动变化范围. 在反演过程中,为了稳定反演结果,本文采用时空光滑约束(Yagi et al,2004 张勇,2008)使子断层的震源时间函数相邻时刻间的差异和相邻子断层间同震滑动量的差异最小化,并将标量地震矩最小约束(Hartzell,Heaton,1983Antolik,Dreger,2003张勇,2008)用于压制较弱的噪声信号对反演结果的影响. 此外,在反演过程中,经过多次尝试,预先给定熊本地震的最大破裂速度为3.0 km/s,子断层最大上升时间为15 s.

    在联合远场P波波形与同震InSAR资料反演此次熊本地震的震源破裂时空过程前,需要给定不同资料间的相对权重值. 在上述选定的破裂速度和子断层上升时间的约束条件下,对同震InSAR资料相对于远场P波资料的权重值进行一维网格搜索(如图3所示). 为了定量地描述反演结果的可靠性,定义方差降VR (Kim,Dreger,2008)用于评估反演结果对资料的解释程度.

    ${{ VR^W}} = \left[ {1 - \frac{{\sum\limits_j {\sum\limits_i {{{\left({d_j^{ W}\left({{t_i}} \right) - s_j^{ W}\left({{t_i}} \right)} \right)}^2}} } }}{{\sum\limits_j {\sum\limits_i {{{\left({d_j^{ W}\left({{t_i}} \right)} \right)}^2}} } }}} \right] \times 100$

    (1)

    ${ V{R^G}} = \left[ {1 - \frac{{\sum\limits_j {{{\left({d_j^{ G} - s_j^{ G}} \right)}^2}} }}{{\sum\limits_j {{{\left({d_j^{ G}} \right)}^2}} }}} \right] \times 100$

    (2)

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    根据不同相对权重值情形下破裂模型对P波波形和同震InSAR资料的平均解释程度(如图3中青色圆圈所示),最终选取用于联合反演的InSAR资料相对于远场P波资料的最佳权重值为5.

    图  3  有限断层联合反演中不同资料相对权重值搜索结果
    Figure  3.  Search result of relative weights between co-seismic InSAR data and teleseismic P waveforms for joint inversion

    图4给出了基于远场体波资料和同震InSAR资料所得的熊本地震破裂过程的联合反演结果,可以看出:该地震的震源破裂持续时间约为25 s,但主要能量集中在前15 s内释放,整个破裂过程释放的总标量矩为6.03×1019 N·m,相当于矩震级MW7.1. 同震滑动主要集中于浅部,破裂以右旋走滑为主,但在沿倾向0—5 km范围内,破裂存在较强的正断特征;在深部区域,滑动以走滑机制为主,兼有较弱的逆冲作用,但鉴于联合反演得到的深部滑动量总体相对较弱,较弱的逆冲分量滑动特征可能是由于反演所用资料对深部滑动约束较弱从而造成反演解的不确定性所致.

    图5给出了此次熊本地震破裂过程的滑动速率快照,可以看出:起始阶段破裂较弱,沿倾向向浅表发生破裂,且破裂沿走向向东北和西南两侧扩展,破裂前期(0—7 s)在走向上无明显的破裂方向性特征;大约7 s之后,破裂沿断层走向主要向东北方向扩展;整个破裂阶段,子断层最大滑动速率约为0.6 m/s,且破裂沿断层走向向西南扩展约10—15 km,背离断层走向向东北扩展约20 km. 此次熊本地震破裂的最大同震滑动量约为4.9 m,且最大同震位错区位于背离断层走向方向、距离起始破裂点5—10 km的范围内(图4). 根据有限断层联合反演结果,此次熊本地震破裂可能出露地表.

    图  4  基于远场体波资料和同震InSAR资料所得的熊本地震破裂过程联合反演结果
    (a) 地震矩率函数;(b) 同震滑动分布,红色圆点表示起始破裂点
    Figure  4.  Joint inversion result of rupture process of the 2016 Kumamoto earthquake from teleseismic P waveforms and co-seismic InSAR data
    (a) Seismic moment rate function; (b) Distribution of co-seismic slip,where the red dot indicates the initial rupture point
    图  5  熊本地震破裂过程滑动速率快照结果。红色圆圈表示起始破裂点位置
    Figure  5.  Snapshots of slip rate for the rupture process of the 2016 Kumamoto earthquake
    The red circles are initial rupture points

    基于联合反演得到的震源破裂时空过程模型,本文合成相应的远场垂直向P波波形资料,并与对应台站处的观测波形资料进行对比,结果如图6所示. 对比结果表明,联合反演模型对波形资料的解释程度(方差降VR值)可达75.6%. 另外,基于有限断层联合反演模型合成同震InSAR资料的视线向(line-of-sight,简写为LOS)位移,并与观测的LOS位移进行对比,结果如图7所示. 结果显示,联合反演模型对同震InSAR资料的解释程度可达71.3%,仅在LOS位移过渡区域有少许观测点所对应的残差值较大.

    图  6  基于联合反演结果的观测波形(黑色)与合成波形(红色)比较
    每幅子图波形的左侧从上至下依次为台站名、震中距(单位:°)和方位角(单位:°),右侧为合成波形与观测波形的相关系数
    Figure  6.  Comparison of the observed waveforms (black) with synthetic ones (red) based on joint inversion results
    On the left side of the waveforms in each subplot are station code,epicentral distance (unit in °) and azimuth (unit in °),and on the right side is correlation coefficient between synthetic waveforms and observed ones
    图  7  同震InSAR观测资料与基于联合反演模型的InSAR合成资料对比
    (a) 观测资料;(b) 合成资料;(c) 残差
    Figure  7.  Comparison of observed and modeled LOS displacements from interferogram
    (a) Observations;(b) Model predictions;(c) Residuals

    针对此次熊本地震的破裂特征,本文分别只利用远场体波资料和同震InSAR资料进行了单独反演,考察单一类型资料对熊本地震破裂时空过程的分辨特征,结果如图8所示. 远场体波单独反演结果(图8a8b)表明此次地震的破裂持续时间亦为25 s,主要破裂集中在前15 s内,同震滑动区主要沿断层倾向朝浅部扩展,最大滑动量约为1.8 m. 基于远场体波反演得到的破裂过程结果的合成波形资料与观测波形资料拟合情况如图9所示. 可以看出,除AAK台的合成波形与观测波形拟合的相关系数为0.68外,其它台站的相关系数均大于0.70,并且所有台站的平均相关系数为0.89,表明单独基于远场体波的反演模型对观测资料具有较好的解释程度.

    远场体波资料反演结果表明,此次熊本地震的滑动机制以走滑为主,但随着深度的增加,滑动特征从正断分量向逆冲分量转变,这可能是由于破裂区区域应力结构的不均匀性分布所致. 与正断分量相比,逆冲分量主要位于破裂区较深的区域,且逆冲分量的滑动量相对较弱. 基于远场体波资料反演的破裂过程结果计算得到此次熊本地震破裂的平均滑动角为−154°,表明此次熊本地震的整体破裂特征以走滑为主,兼有正断分量,这与USGS (2016)给出的W-震相矩张量解也比较一致. 近年来对其它一些灾害性地震破裂过程的研究也发现了相似的破裂机制发生变化的现象(e.g.Hollingsworth et al,2017 张旭等,2017).

    相比于有限断层联合反演结果而言,远场体波单独反演结果的破裂时间过程与联合反演结果基本一致,但同震滑动区范围更广,主要滑动区沿断层走向向西南有所偏移,并且在深部亦有部分破裂,这主要是由于远场体波对破裂过程的空间约束能力较弱、空间分辨率相对较低所致.

    同震InSAR资料单独反演结果(图8c)中的同震滑动空间特征与有限断层联合反演结果相似,但在破裂面浅部(沿断层倾向0—5 km范围内),同震InSAR单独反演结果表明破裂以右旋走滑为主,兼有逆冲分量. 同震InSAR观测资料与基于InSAR单独反演结果合成资料的对比如图10所示. 单独反演同震InSAR资料得到的同震滑动对应的较弱逆冲分量特征,与联合反演结果以及USGS (2016)给出的W-震相矩张量反演结果中对应的正断分量特征相比有些偏差,这可能是由于不同资料的分辨能力差异或不同资料、方法反演解的不确定性所致. 这种差异性在利用地震资料和同震InSAR资料对2016年阿克陶MS6.7强震的震源机制解反演中也有所体现(Feng et al,2017 ).

    本文基于远场体波资料和同震InSAR资料联合反演得到的此次熊本MW7.1地震破裂时空过程的主要特征与已有的分别单独利用远场体波资料(Yagi et al,2016 )、同震InSAR资料(Himematsu,Furuya,2016)和近场强地面运动数据(Hao et al,2017 )所得反演结果基本一致. 同震滑动分布主要集中在较浅区域内,释放的标量地震矩主要集中在大约15 s内释放. 与同震InSAR资料反演结果(Himematsu,Furuya,2016)不同,本文的联合反演结果与Yagi等(2016)Hao等(2017)的结果均显示在破裂面靠近地表的区域内具有较强的滑动分布,表明破裂可能出露地表,这也与震区场地调查得到的沿ENE向延伸的长约30 km的地表破裂较为一致(Shirahama et al,2016 Toda et al,2016 ). 此外,联合反演结果表明正断分量主要集中在破裂面的浅部,而Hao等(2017)的反演结果中正断分量主要集中在破裂面相对较深的区域. 由于此次熊本地震的破裂以走滑为主,正断分量相对较弱,所以对于正断分量的深度分布特征尚需后续结合其它数据和资料进一步分析和讨论.

    图  8  熊本地震破裂过程远场体波单独反演结果及同震InSAR资料单独反演结果
    (a) 远场体波反演得到的破裂过程地震矩率函数;(b) 远场体波反演得到的同震滑动分布;(c) 同震InSAR资料反演得到的同震滑动分布。图(b)中红色虚线方框尺度与图(c)相同
    Figure  8.  Inversion results of teleseismic waveforms and co-seismic InSAR data for the rupture process of the 2016 Kumamoto earthquake
    (a) Seismic moment rate function from inversion result of teleseismic waveforms;(b) Distribution of co-seismic slip from inversion result of teleseismic waveforms;(c) Distribution of co-seismic slip from inversion result of co-seismic InSAR data. The geometric dimensions of the red dotted rectangular in Fig. (b) are the same as in Fig. (c)
    图  9  基于远场体波单独反演结果的观测波形(黑色)与合成波形(红色)比较
    每幅子图波形的左侧从上至下依次为台站名、震中距(单位:°)和方位角(单位:°),右侧为合成波形与观测波形的相关系数
    Figure  9.  Comparison of the observed waveforms (black) and synthetic ones (red) based on the teleseismic body waveform inversion results
    On the left side of the waveforms in each subplot are station code,epicentral distance (unit in °) and azimuth (unit in °),and on the right side is correlation coefficient between synthetic waveforms and observed ones
    图  10  基于同震InSAR数据单独反演结果的LOS合成资料与观测资料对比
    (a) 观测资料;(b) 合成资料;(c) 残差
    Figure  10.  Comparison of observed and modeled LOS displacements from interferogram based on the coseismic InSAR data inversion results
    (a) Observations;(b) Model predictions;(c) Residuals

    地震破裂过程对于地表同震位移变化具有直接的影响(张贝等,2015),可靠的有限断层地震破裂模型有助于地表同震位移变化估计. 我们利用上述基于远场体波和同震InSAR资料的地震破裂过程有限断层联合反演结果,使用Wang等(2003)的方法估计了震区东西、南北及垂直方向的地表同震位移变化(图11). 对于水平方向的地表同震位移变化而言,震区西北区域主要朝东北方向运动,而在东南区域则主要朝南方运动;对于垂直方向而言,震区西北区域地表以下沉为主,而在东南区域地表则有较弱的隆升.

    图  11  基于有限断层联合反演模型的熊本地震震源区东西向(左)、南北向(中)和垂直向(右)的地表同震位移变化估计
    Figure  11.  Estimation of the earth surface co-seismic displacements in E-W (left),N-S (middle) and vertical (right) directions in source region based on the joint inversion result of the rupture process of the 2016 Kumamoto earthquake

    本文中我们利用远场长周期体波资料以及同震InSAR资料联合反演了此次日本熊本地震的震源破裂时空过程结果. 根据联合反演结果,对于此次熊本灾害性地震的破裂复杂性特征,我们有如下认识:

    此次日本熊本地震的震源破裂持续时间约为25 s,但主要能量集中在前15 s内释放,整个破裂过程释放的总标量矩为6.03×1019 N·m,相当于矩震级MW7.1. 同震滑动分布主要集中于浅部,破裂以右旋走滑为主,但在沿倾向0—5 km范围内,破裂存在较强的正断特征,最大同震滑动量约为4.9 m,且最大同震位错区位于背离断层走向、距离起始破裂点约 5—10 km范围内. 破裂前期(0—7 s),在倾向上向浅表发生破裂,在走向上向东北和西南两侧扩展;大概7 s之后,破裂沿断层走向主要向东北方向扩展. 地震破裂过程联合反演结果表明,此次熊本地震破裂可能出露地表.

  • 图  1   熊本MW7.0地震区域构造及其破裂特征

    Figure  1.   Regional tectonic settings and rupture characteristics of the 2016 Kumamoto MW7.0 earthquake

    图  2   用于熊本地震破裂过程联合反演的远场体波台站分布(a)以及同震InSAR资料覆盖区域(b)

    红色星形表示主震震中位置。图(a)中蓝色三角形表示台站;图(b)中红色方框表示InSAR覆盖区域,黑色框表示图1中的展示区域,黑色圆圈表示主震发生后一个月内MW≥4.0余震的震中分布(USGS,2016)

    Figure  2.   Distribution of used teleseismic stations (a) and co-seismic InSAR coverage (b) for joint inversion of rupture process of Kumamoto earthquake

    The red star represents the mainshock epicenter. The blue triangles in Fig.(a) represent the stations. The red rectangular in Fig. (b) is the co-seismic coverage,the black rectangular delineates the region shown in Fig. 1,and black circles are the MW≥4.0 aftershocks within one month after the main shock (USGS,2016)

    图  3   有限断层联合反演中不同资料相对权重值搜索结果

    Figure  3.   Search result of relative weights between co-seismic InSAR data and teleseismic P waveforms for joint inversion

    图  4   基于远场体波资料和同震InSAR资料所得的熊本地震破裂过程联合反演结果

    (a) 地震矩率函数;(b) 同震滑动分布,红色圆点表示起始破裂点

    Figure  4.   Joint inversion result of rupture process of the 2016 Kumamoto earthquake from teleseismic P waveforms and co-seismic InSAR data

    (a) Seismic moment rate function; (b) Distribution of co-seismic slip,where the red dot indicates the initial rupture point

    图  5   熊本地震破裂过程滑动速率快照结果。红色圆圈表示起始破裂点位置

    Figure  5.   Snapshots of slip rate for the rupture process of the 2016 Kumamoto earthquake

    The red circles are initial rupture points

    图  6   基于联合反演结果的观测波形(黑色)与合成波形(红色)比较

    每幅子图波形的左侧从上至下依次为台站名、震中距(单位:°)和方位角(单位:°),右侧为合成波形与观测波形的相关系数

    Figure  6.   Comparison of the observed waveforms (black) with synthetic ones (red) based on joint inversion results

    On the left side of the waveforms in each subplot are station code,epicentral distance (unit in °) and azimuth (unit in °),and on the right side is correlation coefficient between synthetic waveforms and observed ones

    图  7   同震InSAR观测资料与基于联合反演模型的InSAR合成资料对比

    (a) 观测资料;(b) 合成资料;(c) 残差

    Figure  7.   Comparison of observed and modeled LOS displacements from interferogram

    (a) Observations;(b) Model predictions;(c) Residuals

    图  8   熊本地震破裂过程远场体波单独反演结果及同震InSAR资料单独反演结果

    (a) 远场体波反演得到的破裂过程地震矩率函数;(b) 远场体波反演得到的同震滑动分布;(c) 同震InSAR资料反演得到的同震滑动分布。图(b)中红色虚线方框尺度与图(c)相同

    Figure  8.   Inversion results of teleseismic waveforms and co-seismic InSAR data for the rupture process of the 2016 Kumamoto earthquake

    (a) Seismic moment rate function from inversion result of teleseismic waveforms;(b) Distribution of co-seismic slip from inversion result of teleseismic waveforms;(c) Distribution of co-seismic slip from inversion result of co-seismic InSAR data. The geometric dimensions of the red dotted rectangular in Fig. (b) are the same as in Fig. (c)

    图  9   基于远场体波单独反演结果的观测波形(黑色)与合成波形(红色)比较

    每幅子图波形的左侧从上至下依次为台站名、震中距(单位:°)和方位角(单位:°),右侧为合成波形与观测波形的相关系数

    Figure  9.   Comparison of the observed waveforms (black) and synthetic ones (red) based on the teleseismic body waveform inversion results

    On the left side of the waveforms in each subplot are station code,epicentral distance (unit in °) and azimuth (unit in °),and on the right side is correlation coefficient between synthetic waveforms and observed ones

    图  10   基于同震InSAR数据单独反演结果的LOS合成资料与观测资料对比

    (a) 观测资料;(b) 合成资料;(c) 残差

    Figure  10.   Comparison of observed and modeled LOS displacements from interferogram based on the coseismic InSAR data inversion results

    (a) Observations;(b) Model predictions;(c) Residuals

    图  11   基于有限断层联合反演模型的熊本地震震源区东西向(左)、南北向(中)和垂直向(右)的地表同震位移变化估计

    Figure  11.   Estimation of the earth surface co-seismic displacements in E-W (left),N-S (middle) and vertical (right) directions in source region based on the joint inversion result of the rupture process of the 2016 Kumamoto earthquake

  • 张贝, 程惠红, 石耀霖. 2015. 2015年4月25日尼泊尔MS8.1大地震的同震效应[J]. 地球物理学报, 58(5): 1794-1803.

    Zhang B, Cheng H H, Shi Y L. 2015. Calculation of the co-seismic effect of MS8.1 earthquake, Apirl 25, 2015, Nepal[J]. Chinese Journal of Geophysics, 58(5): 1794-1803 (in Chinese).

    张旭. 2016. 基于视震源时间函数的震源过程复杂性分析新方法研究[D]. 北京: 中国地震局地球物理研究所: 1–218.

    Zhang X. 2016. Study on New Methods for Analysis of the Complexity of Source Rupture Process Based on Apparent Source Time Functions[D]. Beijing: Institute of Geophysics, China Earthquake Administration: 1–218 (in Chinese).

    张旭, 严川, 许力生, 李春来. 2017. 2016年阿克陶MS6.7地震震源复杂性与烈度[J]. 地球物理学报, 60(4): 1411-1422.

    Zhang X, Yan C, Xu L S, Li C L. 2017. Source complexity of the 2016 Aketao MS6.7 earthquake and its intensity[J]. Chinese Journal of Geophysics, 60(4): 1411-1422 (in Chinese).

    张勇. 2008. 震源破裂过程反演方法研究[D]. 北京: 北京大学地球与空间科学学院: 1–17.

    Zhang Y. 2008. Study on the Inversion Methods of Source Rupture Process[D]. Beijing: School of Earth and Space Sciences, Peking University: 1–17 (in Chinese).

    Antolik M, Dreger D S. 2003. Rupture process of the 26 January 2001 MW7.6 Bhuj, India, earthquake from teleseismic broadband data[J]. Bull Seismol Soc Am, 93(3): 1235-1248.

    Chen Y T, Xu L S. 2000. A time-domain inversion technique for the tempo-spatial distribution of slip on a finite fault plane with applications to recent large earthquakes in the Tibetan Plateau[J]. Geophys J Int, 143(2): 407-416.

    Farr T G, Rosen P A, Caro E, Crippen R, Duren R, Hensley S, Kobrick M, Paller M, Rodriguez E, Roth L, Seal D, Shaffer S, Shimada J, Umland J, Werner M, Oskin M, Burbank D, Alsdorf D. 2000. The shuttle radar topography mission[J]. Rev Geophys, 45(2): RG2004.

    Feng W P, Tian Y F, Zhang Y, Samsonov S, Almeida R, Liu P. 2017. A slip gap of the 2016 Mw6.6 Muji, Xinjiang, China, earthquake inferred from sentinel-1 TOPS interferometry[J]. Seismol Res Lett, 88(4): 1054-1064. doi: 10.1785/0220170019.

    Fukahata Y, Hashimoto M. 2016. Simultaneous estimation of the dip angles and slip distribution on the faults of the 2016 Kumamoto earthquake through a weak nonlinear inversion of InSAR data[J]. Earth Planets Space, 68: 204.

    GCMT. 2016. Global CMT search results[EB/OL]. [2017-01-07]. http://www.globalcmt.org/cgi-bin/globalcmt-cgi-bin/CMT4/form?itype=ymd&yr=2016&mo=4&day=15&oyr=2016&omo=4&oday=16&jyr=1976&jday=1&ojyr=1976&ojday=1&otype=nd&nday=1&lmw=0&umw=10&lms=0&ums=10&lmb=0&umb=10&llat=-90&ulat=90&llon=-180&ulon=180&lhd=0&uhd=1000<s=-9999&uts=9999&lpe1=0&upe1=90&lpe2=0&upe2=90&list=0.

    Goldstein R M, Werner C L. 1998. Radar interferogram filtering for geophysical applications[J]. Geophys Res Lett, 25(21): 4035-4038.

    Goldstein R M, Zebker H A, Werner C L. 1988. Satellite radar interferometry: Two-dimensional phase unwrapping[J]. Radio Sci, 23(4): 713-720.

    Hao J L, Ji C, Yao Z X. 2017. Slip history of the 2016 Mw7.0 Kumamoto earthquake: Intraplate rupture in complex tectonic environment[J]. Geophys Res Lett, 44(2): 743-750.

    Hartzell S H, Heaton T H. 1983. Inversion of strong ground motion and teleseismic waveform data for the fault rupture history of the 1979 Imperial Valley, California, earthquake[J]. Bull Seismol Soc Am, 73(6A): 1553-1583.

    Himematsu Y, Furuya M. 2016. Fault source model for the 2016 Kumamoto earthquake sequence based on ALOS-2/PALSAR-2 pixel-offset data: evidence for dynamic slip partitioning (EPSP-D-16-00163)[J]. Earth Planets Space, 68(1): 169.

    Hollingsworth J, Ye L L, Avouac J P. 2017. Dynamically triggered slip on a splay fault in the MW7.8, 2016 Kaikoura(New Zealand) earthquake[J]. Geophys Res Lett, 44(8): 3517-3525.

    Kennett B L N, Engdahl E R, Buland R. 1995. Constraints on seismic velocities in the Earth from traveltimes[J]. Geophys J Int, 122(1): 108-124.

    Kim A, Dreger D S. 2008. Rupture process of the 2004 Parkfield earthquake from near‐fault seismic waveform and geodetic records[J]. J Geophys Res, 113(B7): B07308.

    Scheiber R, Moreira A. 2000. Coregistration of interferometric SAR images using spectral diversity[J]. IEEE Trans Geosci Remote Sens, 38(5): 2179-2191.

    Shirahama Y, Yoshimi M, Awata Y, Maruyama T, Azuma T, Miyashita Y, Mori H, Imanishi K, Takeda N, Ochi T, Otsubo M, Asahina D, Miyakawa A. 2016. Characteristics of the surface ruptures associated with the 2016 Kumamoto earthquake sequence, Central Kyushu, Japan[J]. Earth Planets Space, 68: 191.

    Toda S, Kaneda H, Okada S, Ishimura D, Mildon Z K. 2016. Slip-partitioned surface ruptures for the Mw7.0 16 April 2016 Kumamoto, Japan, earthquake[J]. Earth Planets Space, 68: 188.

    Uchide T, Horikawa H, Nakai M, Matsushita R, Shigematsu N, Ando R, Imanishi K. 2016. The 2016 Kumamoto–Oita earthquake sequence: aftershock seismicity gap and dynamic triggering in volcanic areas[J]. Earth Planets Space, 68: 180.

    USGS. 2016. M7.0−1 km, E of Kumamoto-shi, Japan[EB/OL]. [2017-01-07]. https://earthquake.usgs.gov/earthquakes/eventpage/us20005iis#executive.

    Wang R J. 1999. A simple orthonormalization method for stable and efficient computation of Green’s functions[J]. Bull Seismol Soc Am, 89(3): 733-741.

    Wang R J, Martín F L, Roth F. 2003. Computation of deformation induced by earthquakes in a multi-layered elastic crust: FORTRAN programs EDGRN/EDCMP[J]. Comput Geosci, 29(2): 195-207.

    Ward S N, Barrientos S E. 1986. An inversion for slip distribution and fault shape from geodetic observations of the 1983, Borah Peak, Idaho, Earthquake[J]. J Geophys Res, 91(B5): 4909-4919.

    Xu L S, Chen Y T, Teng T L, Patau G. 2002. Temporal-spatial rupture process of the 1999 Chi-Chi earthquake from IRIS and GEOSCOPE long-period waveform data using aftershocks as empirical Green’s functions[J]. Bull Seismol Soc Am, 92(8): 3210-3228.

    Yagi Y, Mikumo T, Pacheco J, Reyes G. 2004. Source rupture process of the Tecomán, Colima, Mexico earthquake of 22 January 2003, determined by joint inversion of Teleseismic body-wave and near-source data[J]. Bull Seismol Soc Am, 94(5): 1795-1807.

    Yagi Y, Okuwaki R, Enescu B, Kasahara A, Miyakawa A, Otsubo M. 2016. Rupture process of the 2016 Kumamoto earthquake in relation to the thermal structure around Aso volcano[J]. Earth Planets Space, 68: 118.

    Yoshida S. 2016. Earthquakes in Oita triggered by the 2016 M7.3 Kumamoto earthquake[J]. Earth Planets Space, 68: 176.

  • 期刊类型引用(3)

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    2. 袁霜,何平,温扬茂,许才军. 综合InSAR和应变张量估计2016年M_W7.0熊本地震同震三维形变场. 地球物理学报. 2020(04): 1340-1356 . 百度学术
    3. 马云漪,卢建旗,李山有,何沛阳. 基于线源模型的中国仪器地震烈度衰减规律. 内陆地震. 2020(04): 330-339 . 百度学术

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  • 收稿日期:  2017-04-16
  • 修回日期:  2017-06-26
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  • 发布日期:  2017-12-31

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