3D numerical model for viscoelastic postseismic deformation following the Maule MW8.8 earthquake in 2010
-
摘要: 2010年智利马乌莱MW8.8地震发生在纳斯卡板块与南美板块的板块边界处，引起了显著的同震和震后效应。GPS台网数据显示记录到的同震海向位移最大约5 m，垂向沉降最大约50 cm。在经过对俯冲效应、季节变化等效应的校正后，震后6年的海向最大位移约68 cm，垂向抬升最大约20 cm。马乌莱地震显著的震后形变对该区域的地下三维黏弹性结构有良好的约束。本文建立了智利中南部俯冲带区域的三维有限元模型，黏弹性的地幔楔及海洋地幔均使用伯格斯体材料，并在断层面上设置2 km厚的软弱层以模拟震后余滑。在与GPS台站震后位移数据进行比较后，模拟结果表明，大洋地幔顶部存在约120 km厚，黏度为1×1019 Pa·s的软流圈。模拟震后余滑效应的软弱层黏度为5×1017 Pa·s，其等效震后余滑的最大值在震后前两年接近2 m，且随着时间的增长而快速衰减。Abstract: The 2010 MW8.8 Maule earthquake occurred near the plate boundary between the Nazca plate and the South American plate. The earthquake produced significant coseismic and postseismic deformation. The maximum coseismic motion is about 5 m in the horizontal direction and about 5 cm subsidence. After correcting the GPS data for secular, seasonal and annual trends, the postseismic cumulative motion within the first 6 years after the earthquake include up to about 68 cm in the horizontal direction and up to 20 cm uplift. The three-dimensional （3D） viscoelastic structure can be constrained by the postseismic deformation of the 2010 earthquake. We have constructed a 3D finite element model to study the effects of the rheological structure on the postseismic deformation of the 2010 earthquake. We assume the viscoelasticrelaxation of the upper mantle to be represented by the Burgers rheology. And in the paper, a 2 km thick weak shear zone attached to the megathrust is used to simulate the afterslip. Based on the comparison with the GPS observation data, the preferred model determined that a 120 km thick asthenosphere with a viscosity of 1×1019 Pa·s at the top of the oceanic upper mantle is required to fit the data. The afterslip simulated by shear zone with a viscosity of 5×107 Pa·s is up to 2 m in the first 2 years and decays rapidly with time.
-
-
![]()
图 1 南美俯冲带2010年马乌莱MW8.8地震构造背景
Figure 1. The tectonic background of the 2010 MW8.8 Maule earthquake in South American subduction zone
![]()
图 2 拟合得到的震间速度场与震后位移场
（a） 震间速度场；（b） 震后六年累积位移场
Figure 2. Fitted interseismic velocity field and postseismic displacement field
（a） Interseismic velocity field；（b） Accumulated postseismic displacement field for 6 years
![]()
图 3 有限元模型
（a） 具有最优参数的有限元模型示意图；（b） 三维有限元网格图
Figure 3. Finite element model
（a） Schematic diagram for FEM with the optimal model parameters；（b） 3D FEM meshes
![]()
图 4 2010年马乌莱MW8.8地震的同震位移图
Figure 4. Coseismic displacement of the MW8.8 Maule earthquake in 2010
![]()
图 5 震后两年震后余滑与各部分黏弹性松弛效应的独立模拟及其综合效应
（a） 软弱层模拟的震后余滑效应；（b） 地幔楔应力松弛效应；（c） 大洋地幔软流圈应力松弛效应；（d） 深部大洋地幔应力松弛效应；（e） 图（a）−（d）的综合效应
Figure 5. Independent simulation of afterslip viscoelastic relaxation effect of each part and its combined effect in 2 years after earthquake
（a） Afterslip effects simulated by weak shear zone；（b） Stress relaxation effects of mantle wedge；（c） Stress relaxation effects of oceanic asthenosphere；（d） Stress relaxation effects of deep oceanic mantle；（e） Combined effects of figs.（a）−（d）
![]()
图 6 模型误差图 （每一个小方块代表一个测试模型）
（a） 仅考虑水平分量误差图；（b） 仅考虑垂直分量误差图；（c） 水平和垂向三分量误差图
Figure 6. Misfits of model results （Each cube represents one test model）
（a） Misfits only considered horizontal component；（b） Misfits only considered vertical component； （c） Misfits considered three-component data
![]()
图 7 最优模型 0—2年（a）、2—4年（b）、 4—6年（c）震后位移图
Figure 7. Postseismic displacement for the optimal model of 0−2 years （a），2−4 years （b） and 4−6 years （c）
-
黄禄渊,张贝,瞿武林,张怀,石耀霖. 2017. 2010智利Maule特大地震的同震效应[J]. 地球物理学报,60(3):972–984. doi: 10.6038/cjg20170312 Huang L Y,Zhang B,Qu W L,Zhang H,Shi Y L. 2017. The co-seismic effects of 2010 Maule earthquake[J]. Chinese Journal of Geophysics,60(3):972–984 (in Chinese).
林鑫,郝金来,姚振兴. 2017. 智利MW8.3地震与MW8.8地震的震源过程及其引起的库仑应力特征[J]. 地球物理学报,60(7):2680–2692. Lin X,Hao J L,Yao Z X. 2017. Rupture process and Coulomb stress change of the MW8.3 earthquake and the MW8.8 earthquake,Chile[J]. Chinese Journal of Geophysics,60(7):2680–2692 (in Chinese).
Aagaard B, Williams C, Knepley M, Williams C. 2017. Computational infrastructure for geodynamics: Software[CP/OL]. [2019-08-05]. https://geodynamics.org/cig/software/pylith.
Bedford J,Moreno M,Baez J C,Lange D,Tilmann F,Rosenau M,Heidbach O,Oncken O,Bartsch M,Rietbrock A,Tassara A,Bevis M,Vigny C. 2013. A high-resolution,time-variable afterslip model for the 2010 Maule MW8.8,Chile megathrust earthquake[J]. Earth Planet Sci Lett,383:26–36. doi: 10.1016/j.jpgl.2013.09.020
Bedford J,Moreno M,Li S Y,Oncken O,Baez J C,Bevis M,Heidbach O,Lange D. 2016. Separating rapid relocking,afterslip,and viscoelastic relaxation:An application of the postseismic straightening method to the Maule 2010 cGPS[J]. J Geophys Res:Solid Earth,121(10):7618–7638. doi: 10.1002/2016JB013093
Blewitt G,Hammond W C,Kreemer Corné K. 2018. Harnessing the GPS data explosion for interdisciplinary science[J]. Eos,99:1–2.
Chen L. 2017. Layering of subcontinental lithospheric mantle[J]. Science Bulletin,62(14):1030–1034. doi: 10.1016/j.scib.2017.06.003
Hayes G P,Wald D J,Johnson R L. 2012. Slab1.0:A three-dimensional model of global subduction zone geometries[J]. J Geophys Res:Solid Earth,117(B1):B01302.
Hicks S P,Rietbrock A,Ryder I M,Lee C S,Miller M. 2014. Anatomy of a megathrust:The 2010 M8.8 Maule,Chile earthquake rupture zone imaged using seismic tomography[J]. Earth Planet Sci Lett,405:142–155. doi: 10.1016/j.jpgl.2014.08.028
Hu Y,Wang K L,He J H,Klotz J,Khazaradze G. 2004. Three-dimensional viscoelastic finite element model for postseismic deformation of the great 1960 Chile earthquake[J]. J Geophys Res:Solid Earth,109(B12):B12403. doi: 10.1029/2004JB003163
Hu Y,Bürgmann R,Banerjee P,Feng L J,Hill E M,Ito T,Tabei T,Wang K L. 2016a. Asthenosphere rheology inferred from observations of the 2012 Indian Ocean earthquake[J]. Nature,538(7625):368–372. doi: 10.1038/nature19787
Hu Y,Bürgmann R,Uchida N,Banerjee P,Freymueller J T. 2016b. Stress-driven relaxation of heterogeneous upper mantle and time-dependent afterslip following the 2011 Tohoku earthquake[J]. J Geophys Res:Solid Earth,121(1):385–411. doi: 10.1002/2015JB012508
Igarashi T,Matsuzawa T,Hasegawa A. 2003. Repeating earthquakes and interplate aseismic slip in the northeastern Japan subduction zone[J]. J Geophys Res:Solid Earth,108(B5):2249.
Klein E,Fleitout L,Vigny C,Garaud J D. 2016. Afterslip and viscoelastic relaxation model inferred from the large-scale post-seismic deformation following the 2010 MW8.8 Maule earthquake (Chile)[J]. Geophys J Int,205(3):1455–1472. doi: 10.1093/gji/ggw086
Klotz J,Khazaradze G,Angermann D,Reigber C,Perdomo R,Cifuentes O. 2001. Earthquake cycle dominates contemporary crustal deformation in Central and Southern Andes[J]. Earth Planet Sci Lett,193(3/4):437–446.
Li S Y,Moreno M,Bedford J,Rosenau M,Heidbach O,Melnick D,Oncken O. 2017. Postseismic uplift of the Andes following the 2010 Maule earthquake:Implications for mantle rheology[J]. Geophys Res Lett,44(4):1768–1776.
Li S Y,Bedford J,Moreno M,Barnhart W D,Rosenau M,Oncken O. 2018. Spatio-temporal variation of mantle viscosity and the presence of cratonic mantle inferred from 8 years of postseismic deformation following the 2010 Maule,Chile,earthquake[J]. Geochem,Geophys,Geosyst,19(9):3272–3285.
Moreno M,Melnick D,Rosenau M,Baez J,Klotz J,Oncken O,Tassara A,Chen J,Bataille K,Bevis M,Socquet A,Bolte J,Vigny C,Brooks B,Ryder I,Grund V,Smalley B,Carrizo D,Bartsch M,Hase H. 2012. Toward understanding tectonic control on the MW8.8 2010 Maule Chile earthquake[J]. Earth Planet Sci Lett,321-322:152–165. doi: 10.1016/j.jpgl.2012.01.006
Oncken O, Chong G, Franz G, Giese P, Götze H J, Ramos V A, Strecker M R, Wigger P. 2006. The Andes: Active Subduction Orogeny[M]. Berlin, Heidelberg: Springer Science & Business Media: 443–457.
Ruegg J C,Rudloff A,Vigny C,Madariaga R,de Chabalier J B,Campos J,Kausel E,Barrientos S,Dimitrov D. 2009. Interseismic strain accumulation measured by GPS in the seismic gap between Constitución and Concepción in Chile[J]. Phys Earth Planet Inter,175(1/2):78–85.
Sun T H,Wang K L,He J H. 2018. Crustal deformation following great subduction earthquakes controlled by earthquake size and mantle rheology[J]. J Geophys Res:Solid Earth,123(6):5323–5345. doi: 10.1029/2017JB015242
Tong X P,Sandwell D,Luttrell K,Brooks B,Bevis M,Shimada M,Foster J,Smalley Jr R,Parra H,Soto J C B,Blanco M,Kendrick E,Genrich J,Caccamise II D J. 2010. The 2010 Maule,Chile earthquake:Downdip rupture limit revealed by space geodesy[J]. Geophys Res Lett,37(24):L24311.
Uchida N,Matsuzawa T. 2013. Pre- and postseismic slow slip surrounding the 2011 Tohoku-Oki earthquake rupture[J]. Earth Planet Sci Lett,374:81–91. doi: 10.1016/j.jpgl.2013.05.021
Utada H,Kiyoshi B. 2014. Estimating the electrical conductivity of the melt phase of a partially molten asthenosphere from seafloor magnetotelluric sounding data[J]. Phys Earth Planet Inter,227:41–47. doi: 10.1016/j.pepi.2013.12.004
Wang K L,Hu Y,Bevis M,Kendrick E,Smalley Jr R,Vargas R B,Lauría E. 2007. Crustal motion in the zone of the 1960 Chile earthquake:Detangling earthquake-cycle deformation and forearc-sliver translation[J]. Geochem,Geophys,Geosyst,8(10):Q10010.
Wang K L,Hu Y,He J H. 2012. Deformation cycles of subduction earthquakes in a viscoelastic Earth[J]. Nature,484(7394):327–332. doi: 10.1038/nature11032
Watts A B,Zhong S. 2000. Observations of flexure and the rheology of oceanic lithosphere[J]. Geophys J Int,142(3):855–875. doi: 10.1046/j.1365-246x.2000.00189.x
Weiss J R,Qiu Q,Barbot S,Wright T J,Foster J H,Saunders A,Brooks B A,Bevis M,Kendrick E,Ericksen T L,Avery J,Smalley Jr R,Cimbaro S R,Lenzano L E,Barón J,Báez J C,Echalar A. 2019. Illuminating subduction zone rheological properties in the wake of a giant earthquake[J]. Sci Adv,5(12):eaax6720. doi: 10.1126/sciadv.aax6720
Yue H,Lay T,Rivera L,An C,Vigny C,Tong X P,Soto J C B. 2014. Localized fault slip to the trench in the 2010 Maule,Chile MW8.8 earthquake from joint inversion of high-rate GPS,teleseismic body waves,InSAR,campaign GPS,and tsunami observations[J]. J Geophys Res:Solid Earth,119(10):7786–7804. doi: 10.1002/2014JB011340
-
期刊类型引用(11)
1. 梁珍，乔国文，李治财，王涛，赵龙，曾召田. 中天山花岗岩深埋隧道高地应力测试及工程影响分析. 现代隧道技术. 2024(S1): 332-341 . 
百度学术
2. 李艳永，王成虎，朱皓清，乌尼尔. 北天山地区震源机制与构造应力场特征. 地震. 2020(02): 117-129 . 百度学术
3. 刘兆才，万永革，黄骥超，靳志同，杨帆，李瑶. 2017年精河M_S6.6地震邻区构造应力场特征与发震断层性质的厘定. 地球物理学报. 2019(04): 1336-1348 . 百度学术
4. 李艳永，王成虎，杨佳佳. 呼图壁地区震源机制解及构造应力场特征分析. 大地测量与地球动力学. 2018(12): 1246-1250 . 百度学术
5. 万永革. 联合采用定性和定量断层资料的应力张量反演方法及在乌鲁木齐地区的应用. 地球物理学报. 2015(09): 3144-3156 . 百度学术
6. 孙业君，刘红桂，江昊琳，詹小艳，王俊菲，丁烨，叶碧文. 江苏南部地区现今震源机制和应力场特征. 地震研究. 2015(02): 203-210 . 百度学术
7. 刘旭东，孙秉成，荣海. 乌东矿区地质断裂构造对冲击地压的影响. 内蒙古煤炭经济. 2015(06): 205-207 . 百度学术
8. 丁亮，高尔根，孙守才，邓晓果，刘骁. 天山活动地块地震的震源机制. 防灾科技学院学报. 2014(02): 42-48 . 百度学术
9. 蓝航. 近直立特厚两煤层同采冲击地压机理及防治. 煤炭学报. 2014(S2): 308-315 . 百度学术
10. 郑建常，王鹏，李冬梅，赵金花，徐长朋. 使用小震震源机制解研究山东地区背景应力场. 地震学报. 2013(06): 773-784 . 本站查看
11. 黄龙现，杨天鸿，李现光，郑超. 地应力场方向对巷道围岩稳定性的影响. 中国矿业. 2012(04): 105-107+118 . 百度学术
其他类型引用(6)
下载:
计量
- 文章访问数: 1429
- HTML全文浏览量: 530
- PDF下载量: 161
- 被引次数: 17
