India and Sunda plates motion and deformation along their boundary in Myanmar determined by GPS
India and Sunda plates motion and deformation along their boundary in Myanmar determined by GPS
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DOI：
10.1029/2005jb003877
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发表时间：
2006-05
影响因子：
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通讯作者：
A. Socquet;C. Vigny;N. Chamot‐Rooke;W. Simons;C. Rangin;B. Ambrosius
中科院分区：
文献类型：
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作者：
A. Socquet;C. Vigny;N. Chamot‐Rooke;W. Simons;C. Rangin;B. Ambrosius
使用区域GPS数据集，包括？190站在亚洲，从尼泊尔到印度尼西亚东部，跨越11年，我们更新现在？印度板块与巽他兰板块的相对运动，讨论了缅甸境内印度板块与巽他兰板块之间的变形。重新审视在尼泊尔主边界冲断层上获得的测量结果，似乎尼泊尔南部的点相对于印度大陆的变形可以忽略不计。包括这些点，使用比以前的研究更长的时间跨度，并在最新的参考框架中制作精确的大地测量图，使我们能够完善现在？日印第安运动。我们的研究结果证实，目前的运动印度是慢于预测的NUVEL？1A模型，除了我们的印度？欧亚大陆运动显著（？5毫米/年）比以前的大地测量慢。这种新的印度运动，再加上对巽他大陆运动的精确测定，就让位于相对的印度了吗？在ITRF 2000中，巽他角速度为20.2°N，26.1°E，0.370°/Myr，预测缅甸纬度N10°方向的相对运动为35 mm/yr。在那里，实皆市断层只容纳18毫米/年的权利？横向走滑，只有一半的剪切运动分量。我们提出了两个模型，解决如何以及在哪里剩余的变形可能会发生。第一个模型的分布变形意味着收敛的阿拉干俯冲（北方继续现在著名的苏门答腊？安达曼海沟）和阿拉干楔中的扭动断层。第二个模型使用局部变形，在实皆市断层以西观察到的变形完全是由于更快和倾斜的若开俯冲（23毫米/年）上的弹性载荷。后一种模型预测，在俯冲带的这一段，每世纪可能发生一次Mw 8.5的大地震。
Using a regional GPS data set including ?190 stations in Asia, from Nepal to eastern Indonesia and spanning 11 years, we update the present?day relative motion between the Indian and Sundaland plates and discuss the deformation taking place between them in Myanmar. Revisiting measurements acquired on the Main Boundary Thrust in Nepal, it appears that points in southern Nepal exhibit negligible deformation with respect to mainland India. Including these points, using a longer time span than previous studies, and making an accurate geodetic mapping in the newest reference frame allows us to refine the present?day Indian motion. Our results confirm that the current motion of India is slower than predicted by the NUVEL?1A model, and in addition our India?Eurasia motion is significantly (?5 mm/yr) slower than previous geodetic determinations. This new Indian motion, combined with a refined determination of the Sundaland motion, gives way to a relative India?Sunda angular velocity of 20.2°N, 26.1°E, 0.370°/Myr in ITRF2000, predicting a relative motion of 35 mm/yr oriented N10° at the latitude of Myanmar. There, the Sagaing Fault accommodates only 18 mm/yr of right?lateral strike slip, only half of the shear component of motion. We present two models addressing how and where the remaining deformation may occur. A first model of distributed deformation implies convergence on the Arakan subduction (the northern continuation of the now famous Sumatra?Andaman Trench) and wrench faulting in the Arakan wedge. The second model uses localized deformation, where deformation observed west of the Sagaing Fault is entirely due to elastic loading on a faster and oblique Arakan subduction (23 mm/yr). This latter model predicts that a major earthquake of Mw 8.5 may occur every century on this segment of the subduction.