由GPS测量得到的喜马拉雅的现今构造变形

The Current Tectonic Deformation of Himalaya Range Obtained from GPS Measurement

根据新的GPS观测结果建立西喜马拉雅(WH)、中喜马拉雅(CH)和东喜马拉雅(EH)块体的弹性运动模型。将块体运动分解为整体旋转与内部变形。WH向北运动,平均速率31.5 mm/a;CH NNE向运动,平均速率31.1 mm/a;EH NE向运动,平均速率27.0 mm/a.喜马拉雅山在总体上呈现S-N向缩短与NWW-SEE向伸展。山脉中部S-N向的缩短速率最大平均14.6 mm/a,大约吸收了印度与欧亚板块汇聚速率的35.7%。山脉存在明显的NWW-SEE向伸展变形,西部与东北部之间E-W方向的伸展速率为11.0 mm/a.山脉中段南边界的主压应变率最大,都大于7.5×10-8/a,而主张应变率最小,都小于1.0×10-8/a.山脉的西南角与EH的西北部主张应变率最大,都大于3.7×10-8/a.印度板块对欧亚板块的强烈碰撞与持续推挤力,重力势能差和上地幔的拖曳力是喜马拉雅山现今构造变形的主要驱动力。

Based on the new GPS measurement we created elastic motion models of Western Himalaya （WH）, Central Himalaya （CH） and Eastern Himalaya （EH） blocks. We resolve block＇s motion into entire rotation and its interior deformation. WH block shows a consistent northward motion with average velocity of 31.5 mm/a. CH block shows a consistent NNE-trending motion with average velocity of 31.1 mm/a. EH block shows a consistent NE-trending motion with average velocity of 27.0 mm/a. The Himalaya range shows in totality a status with S-N-trending shortening and NWW-SEE-trending extension. The S-N-trending shortening velocity has maximum value of 14.6 mm/a in range＇ s central part, S-N-trending shortening has absorbed approximately 35.7 % of convergence velocity between In- dia and Eurasian plates. The range exists obvious NWW-SEE-trending extensive, the E-W-trending extensive velocity is 11.0 mm/a between range＇ s western part and northeastern part. In range＇ s central section, nearby southern boundary principal compression strain velocities are maximum, larger than 7.5 × 10^-8/a, and principal tensile strain velocities are minimum, less than 1.0 × 10 ^-8/a. In range＇ s southwestern corners and northwestern part of EH block the principal tensile velocities are maximum, larger than 3.7 × 10^-8/a. The intense collision and continuous push force from India plate to Eurasia plate, the gravity potential energy difference and pulling force in the upper mantle are main driving forces of current tectonic deformation of Himalaya range.