前言自晚古生代以来,西藏高原曾是岛弧或大陆碎块向北增生于欧亚大陆的场所。这一过程直到始新世,当印度与欧亚大陆沿雅鲁藏布江缝合线碰撞、南部特提斯闭合时告终。西藏地壳厚度极大(70km),其高原迅速上升,可能是由于印度陆块俯冲在西藏地壳底下,或是西藏地壳内部的缩短和增厚。西藏高原地震上是活跃的,而且断层面解表明,除喜马拉雅山以下南部的低角度逆断层以外,西藏高原的活动构造以东西向拉伸占优 Preface Since the Late Paleozoic, the Tibetan Plateau was once a place where the island arc or continental fragments proliferated northward in Eurasia. This process did not take place until the Eocene, when India and Eurasia collided along the Brahmaputra suture and the southern Tethys closed. The crust is extremely thick (70km) in Tibet and its plateau is rapidly rising. This may be due to the subduction of the Indian land mass beneath the Tibetan crust or the shortening and thickening of the interior of the Tibetan crust. Earthquakes on the Tibetan Plateau are active, and the fault surface solutions show that except for the low-angle thrust faults in the southern area below the Himalayas, the active structure of the Tibetan Plateau is dominated by east-west stretching