汶川地震由地壳收缩造成
作为喜马拉雅山东缘的龙门山山系，比青藏高原上任何地方的地形起伏都大。它是2008年汶川7.9级大地震的发生地。
在这次地震之前，无论是测地学还是地 质学测量工作都没有测出该山系前端有明显收缩现象，从而引发了关于产生该山系之地形的作用力的激烈争论。
现在，Judith Hubbard 和 John Shaw发表了来自平衡的地质横断面的证据，该证据表明，地壳收缩是龙门山和青藏高原隆起的一个主要作用力，2008年汶川地震是这一收缩过程的一个结果。
汶川地震由地壳收缩造成
汶川地震由地壳收缩造成
Nature 458 , 194-197 (12 March 2009) | doi :10.1038/nature07837 ; Received 11 June 2008; Accepted 27 January 2009
Uplift of the Longmen Shan and Tibetan plateau, and the 2008 Wenchuan ( M = 7.9) earthquake
Judith Hubbard 1 & John H. Shaw 1
1. Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, Massachusetts 02138, USA
The Longmen Shan mountain range, site of the devastating 12 May 2008 Wenchuan ( M = 7.9) earthquake, defines the eastern margin of the Himalayan orogen and exhibits greater topographic relief than anywhere else in the Tibetan plateau. However, before the earthquake, geodetic and geologic surveys measured little shortening across the range front , inspiring a vigorous debate about the process by which the topography of the mountain belt is produced and maintained. Two endmember models have been proposed: (1) brittle crustal thickening, in which thrust faults with large amounts of slip that are rooted in the lithosphere cause uplift , and (2) crustal flow, in which low-viscosity material in the lower crust extrudes outward from the Tibetan plateau and inflates the crust north and east of the Himalayas . Here we use balanced geologic cross-sections to show that crustal shortening, structural relief, and topography are strongly correlated in the range front. This suggests that crustal shortening is a primary driver for uplift and topography of the Longmen Shan on the flanks of the plateau. The 2008 Wenchuan ( M = 7.9) earthquake, which ruptured a large thrust fault along the range front causing tens of thousands of fatalities and widespread damage, is an active manifestation of this shortening process.
Full text ：http://www.nature.com/nature/journal/v458/n7235/full/nature07837.html
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