顾及下地壳拖曳力的川滇地区地表形变有限元数值模拟

doi:10.7523/j.issn.2095-6134.2021.01.001

中国科学院大学学报 ›› 2021, Vol. 38 ›› Issue (1): 1-8.DOI: 10.7523/j.issn.2095-6134.2021.01.001

• 创新前沿 • 下一篇

顾及下地壳拖曳力的川滇地区地表形变有限元数值模拟

尹迪¹, 董培育², 石耀霖¹

1. 中国科学院大学地球与行星科学学院中国科学院计算地球动力学重点实验室, 北京 100049;
2. 中国地震局地震研究所地震大地测量重点实验室, 武汉 430071

收稿日期:2019-09-10 修回日期:2019-11-22 发布日期:2021-03-05
通讯作者: 董培育
基金资助:
国家自然科学基金重大项目（41590865）、国家自然科学基金-中国地震局地震科学联合基金（U1839207）和国家自然科学基金（41704101）资助

Numerical simulation of surface deformation in Sichuan-Yunnan region considering the drag forces underneath the lower crust

YIN Di¹, DONG Peiyu², SHI Yaolin¹

1. Key Laboratory of Computational Dynamics of CAS, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;
2. Key Laboratory of Earthquake Geodesy, Institute of Seismology, China Earthquake Administration, Wuhan 430071, China

Received:2019-09-10 Revised:2019-11-22 Published:2021-03-05

摘要/Abstract

摘要： 在川滇地区，GPS观测资料揭示了其运动方向为东向—东南向，呈现顺时针旋转的趋势。已有研究表明该区域的下地壳是柔性的，且运动速度快于脆性的上地壳并对其具有拖曳作用，这是造成该区域独特运动特征的主要因素。因此在数值模拟区域形变场时，仅考虑弹性作用是不够的，还需要考虑柔性下地壳的拖曳力作用。拖曳力的分布通常采用人工分区和试错法得到，主观性较强。根据川滇地区的构造活动特征建立二维有限元弹性平面模型，以GPS观测数据为约束，利用未施加拖曳力时的计算结果与实际观测结果之间的位移残差ΔUx，ΔUy与各点位坐标x，y的拟合关系式反映研究区域柔性下地壳对上地壳的拖曳力作用。计算结果表明：拖曳力主要集中在川滇菱形块体内，且块体北部的值最大，高达1.0e8 N，并以南向为主；块体南部拖曳力逐渐减小，约为4.0e7 N，方向上逐渐向东西两侧分流。拖曳力以等效体力的形式加载至模型中，可得到与实测形变场吻合度较高的结果。该方法可以为川滇地区长期地表形变动力学机制的研究提供一种物理上更加合理、方法上更加简洁的新思路。

关键词: 川滇地区, 拖曳力, 多项式拟合, 有限元模拟

Abstract: In the Sichuan-Yunnan region, GPS observations reveal that the direction of movement is east-southeast, showing a clockwise rotation trend. In previous studies, it is noted that the lower crust of this region is ductile and moves faster than the brittle upper crust. Consequently, there is a drag force on the bottom of the upper crust, which is the main factor causing the distinct movement characteristics. Therefore, in the study of numerical simulation of regional deformation, it is not enough to consider only the elastic factor, but also the drag force. The distribution of the regional drag force is usually calculated by manual partitioning and trial and error method, which relies on subjective judgment. In this study, a two-dimensional elastic plane model is established based on the regional tectonic activities and the GPS observations as the constrained condition. The regional drag force inversion calculated through the polynomial fitting relationship between the residual values (ΔUx, ΔUy) and the coordinates of each observation point. And the residual values are the difference between the simulation result without the drag force and the observation data. The result shows that the drag force is mainly concentrated in the rhombus block, and the value in the north part is the largest (1e8 N), which is in the south direction. The drag force in the south of the block is gradually decreasing (4e7 N), and the direction is gradually diverted to the east and west sides. Finally, the drag force is applied to the finite element model in the form of equivalent body force, and the simulated result is in good agreement with the observation data. This method provides a new idea for the study of long-term deformation in Sichuan-Yunnan region, which is more reasonable and simpler.

Key words: Sichuan-Yunnan region, drag force, polynomial fitting, finite element simulation

中图分类号:

P315.7

尹迪, 董培育, 石耀霖. 顾及下地壳拖曳力的川滇地区地表形变有限元数值模拟[J]. 中国科学院大学学报, 2021, 38(1): 1-8.

YIN Di, DONG Peiyu, SHI Yaolin. Numerical simulation of surface deformation in Sichuan-Yunnan region considering the drag forces underneath the lower crust[J]. Journal of University of Chinese Academy of Sciences, 2021, 38(1): 1-8.

参考文献

[1] 曹建玲,石耀霖,张怀,等.青藏高原GPS位移绕喜马拉雅东构造结顺时针旋转成因的数值模拟[J].科学通报,2009,54(2):224-234.
[2] Wang Q, Zhang P Z, Freymueller J T,et al. Present-day crustal deformation in China constrained by global positioning system measurements[J]. Science, 2001,294(5542):574-577.
[3] Zheng G, Wang H, Wright T J,et al. Crustal deformation in the India-Eurasia collision zone from 25 years of GPS measurements:crustal deformation in Asia from GPS[J]. Journal of Geophysical Research Solid Earth, 2017, 122(11):9290-9312.
[4] 张培震,邓起东,张国民,等.中国大陆的强震活动与活动地块[J].中国科学D辑:地球科学,2003,33(S1):12-20.
[5] 马宏生,张国民,周龙泉,等.川滇地区中小震重新定位与速度结构的联合反演研究[J].地震,2008,28(2):29-38.
[6] 王椿镛,韩渭宾,吴建平,等.松潘-甘孜造山带地壳速度结构[J].地震学报,2003,25(3):229-241,342.
[7] 姜光政,高堋,饶松,等.中国大陆地区大地热流数据汇编(第四版)[J].地球物理学报,2016,59(8):2892-2910.
[8] 朱守彪,石耀霖.用遗传有限单元法反演川滇下地壳流动对上地壳的拖曳作用[J].地球物理学报,2004,47(2):232-239.
[9] 王辉,曹建玲,张怀,等.川滇地区下地壳流动对上地壳运动变形影响的数值模拟[J].地震学报,2007,29(6):581-591,671.
[10] 庞亚瑾,程惠红,张怀,等.青藏高原东缘岩石圈结构对现今地表垂向运动影响的数值分析[J].地球物理学报,2019,62(4):1256-1267.
[11] 石耀霖,孙云强,罗纲,等.关于我国地震数值预报路线图的设想:汶川地震十周年反思[J].科学通报,2018,63(19):1865-1881.
[12] 董培育,胡才博,石耀霖. 青藏高原及周边区域地表长期变形数值模拟[J].地震地质,2016,38(2):410-422.
[13] Shen Z K, Lv J N, Wang M, et al. Contemporary crustal deformation around the southeast borderland of the Tibetan Plateau[J]. Journal of Geophysical Research Solid Earth, 2005, 110(B11):409-425.
[14] He J K, Lu S J, Wang W M. Three-dimensional mechanical modeling of the GPS velocity field around the northeastern Tibetan plateau and surrounding regions[J].Tectonophysics, 2013,584(SI):257-266.
[15] 徐锡伟,闻泽学,郑荣章,等.川滇地区活动块体最新构造变动样式及其动力来源[J].中国科学D辑:地球科学,2003,33(S1):151-162.
[16] 乔学军,王琪,杜瑞林. 川滇地区活动地块现今地壳形变特征[J].地球物理学报,2004,47(5):806-812.
[17] 邓起东,张培震,冉永康,等.中国活动构造与地震活动[J].地学前缘,2003,10(S1):66-73.
[18] 韦伟,孙若昧,石耀霖. 青藏高原东南缘地震层析成像及汶川地震成因探讨[J].中国科学D辑:地球科学,2010,40(7):831-839.
[19] 陈化然,陈连旺,马宏生,等. 川滇地区应力场演化与强震间相互作用的三维有限元模拟[J].地震学报,2004,26(6):567-575.
[20] Royden L H, Clark B B, Van Der Hilst R D. The geological evolution of the Tibetan Plateau[J]. Science, 2008,321(5892):1054-1058.
[21] 武艳强,江在森,杨国华,等.汶川地震前GPS资料反映的应变率场演化特征[J].大地测量与地球动力学,2011,31(5):20-25,29.
[22] 魏文薪,江在森,刘晓霞,等.川滇地区应变率场分布及其变化特征研究[J].地震,2015,35(4):11-20.
[23] 张培震.青藏高原东缘川西地区的现今构造变形、应变分配与深部动力过程[J].中国科学D辑:地球科学,2008,38(9):1041-1056.
[24] 唐荣昌,韩渭宾.四川活动断裂与地震[M].北京:地震出版社,1993.

顾及下地壳拖曳力的川滇地区地表形变有限元数值模拟

Numerical simulation of surface deformation in Sichuan-Yunnan region considering the drag forces underneath the lower crust

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