汶川地震震前龙门山以西地壳垂直隆升机理分析
|
摘要
结合流动GPS观测速度场及层析成像结果,构建跨龙门山断裂剖面的二维有限元分层模型,分两种情况讨论汶川地震前龙门山前缘地壳垂直隆升的物理机制,以及中、下地壳软物质垂向和横向的不均匀性对地壳隆升作用的影响。分析认为:川西高原相对四川盆地的差异抬升和龙门山以西地壳缩短的共同作用是汶川地震震前龙门山前缘地壳垂直隆升的可能原因。
The mechanism of the vertical uplift of crust in the west of Longmenshan before Wenchuan Ms8.0 earthquake has been debated through constructing the 2-D FEM model for the profile across Longmenshan fault,which is based on the velocity field that had calculated from the GPS observations and the result of seismic tomography obtained by Wu Jiangping et al.In addition,the effect of crustal inhomogeneity on the vertical uplift has been discussed as well.We concluded that the existence of the low velocity anomaly in the low cust below the front of Longmenshan fault play a key role,and vertical uplift is likely caused by both the curst shorten of the westen Longmenshan and the differential uplift between Chuanxi pletau and Sichuan basin.
The mechanism of the vertical uplift of crust in the west of Longmenshan before Wenchuan Ms8.0 earthquake has been debated through constructing the 2-D FEM model for the profile across Longmenshan fault,which is based on the velocity field that had calculated from the GPS observations and the result of seismic tomography obtained by Wu Jiangping et al.In addition,the effect of crustal inhomogeneity on the vertical uplift has been discussed as well.We concluded that the existence of the low velocity anomaly in the low cust below the front of Longmenshan fault play a key role,and vertical uplift is likely caused by both the curst shorten of the westen Longmenshan and the differential uplift between Chuanxi pletau and Sichuan basin.
引文
1王庆良,等.龙门山及汶川Ms8.0级地震垂直形变场研究[J].国际地震动态,2010,(6):11.(Wang Qingliang,etal.Studies on surface vertical deformation of the Longmen-shan in the Wenchuan Ms8.0 earthquake[J].Recent Devel-opments In World Seismology,2010,(6):11)
2 Wang Q L,Cui D X and Zhang X.Coseismic vertical de-formation of theMs8.0 Wenchuan earthquake from repeatedlevelings and its constraint on listric fault geometry[J].Earth Sciences,2009,22:595-602)
3张竹琪,张培震,王庆良.龙门山高倾角逆断层结构与孕震机制[J].地球物理学报,2010,53(9):2 068-2 082.(Zhang Zhuqi,Zhang Peizhen and Wang Qingliang.Thestructure and seismogenic mechanism of Longmenshan Highdip-angle reverse fault[J].Chinese J Geophys.,2010,53(9):2068-2082)
4滕吉文,等.汶川Ms8.0地震发生的深层动力学过程和动力学响应[J].地球物理学报,2008,51(5):1 385-1 402.(Teng Jiwen,et al.Deep processes and dynamic re-sponses associated with the Wenchuan Ms8.0 earthquake of2008[J].Chinese J Geophys.,2008,51(5):1 385-1 402)
5吴建平,等.汶川Ms8.0级地震余震分布及周边区域P波三维速度结构研究[J].地球物理学报,2009,52(2):321-328(Wu Jianping,et al.Aftershock distribution of theMs8.0 Wenchuan earthquake and three dimensional P-wavevelocity structure and around source region[J].Chinese JGeophys.,2009,52(2):321-328)
6朱守彪,张培震.2008年汶川8.0地震发生过程的动力学机制研究[J].地球物理学报,2009,52(2):418-427.(Zhu Shoubiao and Zhang Peizhen.A study on the dynamicalmechanisms of the Wenchuan Ms8.0 earthquake,2008[J].Chinese J Geophys.,2009,52(2):418-427)
7 Hubbard J and Shaw J.Uplift of the Longmenshan and Ti-betan plateau,and the 2008 Wenchuan(M=7.9)earth-quake[J].Nature,2009,458:194-197.
8 Burchfiel B C,et al.A geological and geophysical context forthe Wenchuan earthquake of 12 May 2008,Sichuan,PeopleRepublic of China[J].GSA Today,18(7):4-11.
2 Wang Q L,Cui D X and Zhang X.Coseismic vertical de-formation of theMs8.0 Wenchuan earthquake from repeatedlevelings and its constraint on listric fault geometry[J].Earth Sciences,2009,22:595-602)
3张竹琪,张培震,王庆良.龙门山高倾角逆断层结构与孕震机制[J].地球物理学报,2010,53(9):2 068-2 082.(Zhang Zhuqi,Zhang Peizhen and Wang Qingliang.Thestructure and seismogenic mechanism of Longmenshan Highdip-angle reverse fault[J].Chinese J Geophys.,2010,53(9):2068-2082)
4滕吉文,等.汶川Ms8.0地震发生的深层动力学过程和动力学响应[J].地球物理学报,2008,51(5):1 385-1 402.(Teng Jiwen,et al.Deep processes and dynamic re-sponses associated with the Wenchuan Ms8.0 earthquake of2008[J].Chinese J Geophys.,2008,51(5):1 385-1 402)
5吴建平,等.汶川Ms8.0级地震余震分布及周边区域P波三维速度结构研究[J].地球物理学报,2009,52(2):321-328(Wu Jianping,et al.Aftershock distribution of theMs8.0 Wenchuan earthquake and three dimensional P-wavevelocity structure and around source region[J].Chinese JGeophys.,2009,52(2):321-328)
6朱守彪,张培震.2008年汶川8.0地震发生过程的动力学机制研究[J].地球物理学报,2009,52(2):418-427.(Zhu Shoubiao and Zhang Peizhen.A study on the dynamicalmechanisms of the Wenchuan Ms8.0 earthquake,2008[J].Chinese J Geophys.,2009,52(2):418-427)
7 Hubbard J and Shaw J.Uplift of the Longmenshan and Ti-betan plateau,and the 2008 Wenchuan(M=7.9)earth-quake[J].Nature,2009,458:194-197.
8 Burchfiel B C,et al.A geological and geophysical context forthe Wenchuan earthquake of 12 May 2008,Sichuan,PeopleRepublic of China[J].GSA Today,18(7):4-11.
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心