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利用1992~2006年间境内外天山地区近400个测站的GPS观测,获取天山现今地壳运动速度场,并借助二维弹性位错模型估算了区域内主要断层的活动速率.结果显示天山地区北西走向的走滑断层(如塔拉斯-费尔干纳断裂)的滑移速率仅为1~4mm/a,而近东西走向、低倾角的山前主滑脱断层的滑动速率在西南天山达10~13mm/a,境外北天山为6~12mm/a,东天山为2~5mm/a.GPS速度场显示天山南北向汇聚变形分布不均匀,天山内部缩短变形相对较小,其两侧山盆交接地带的变形占总汇聚变形的80%~90%.研究认为天山压缩变形分布与两侧刚性地块沿主滑脱断层向天山下挤入活动有关,有历史记录的7~8级大震多发生在主滑脱断层闭锁与蠕滑的交接部位.主滑脱断层闭锁使弹性应变集中于山盆过渡带地壳盖层内,通过周期性大震活动释放,天山整体上作为一个楔状弹性地块,整体抬升且向两侧持续扩展.
Using the GPS observations of nearly 400 stations in the Tianshan Mountains at home and abroad during 1992-2006, the velocity field of the present crustal movement in the Tianshan Mountains was obtained and the velocity of the major faults in the area was estimated by means of two-dimensional elastic dislocation models. The results show that the northwest trending of the Tianshan Mountains (Such as Taras-Fergana fault) slip rate of only 1 ~ 4mm / a, and the easterlies, low dip angle slippery rate of the main detachment fault in the Southwest Tianshan up to 10 ~ 13mm / a, the outer North Tianshan is 6 ~ 12mm / a, the East Tianshan is 2 ~ 5mm / a.GPS velocity field shows that the Tianshan converge deformation distribution is not uniform in the north and south, Tianshan internal shortening deformation is relatively small, The deformation of the belt accounts for 80% -90% of the total deformation. The study shows that the Tianshan compression deformation distribution is related to the squeezing into the Tianshan Mountains along the main detachment fault on both sides of the rigid block. There are many historical records of magnitude 8-8 earthquakes At the interface between the main detachment fault blockage and the creep slip, the main detachment fault lock causes the elastic strain to concentrate in the crust caprock of the transitional zone of the basin. Through the release of the cyclically large earthquakes, the Tianshan is generally raised as a wedge-shaped elastic block And continue to expand on both sides.