青藏高原东北缘近期地壳水平运动研究  

RECENT HORIZONTANL VELOCITY FIELD OF NORTHEASTERN TIBETAN PLATEAU

作　　者：郝明[1] 秦姗兰[1] 李煜航[1] 王文萍[1] 周琳[1] 

机构地区：[1]中国地震局第二监测中心,西安710054

出　　处：《大地测量与地球动力学》2014年第3期99-103,共5页Journal of Geodesy and Geodynamics

基　　金：国家自然科学基金项目(41174083);地震行业科研专项(201208009);陕西省科技计划项目(2012SF2-17)

摘　　要：对2011-2013年7月的3期流动GPS最新观测资料进行处理,获取青藏高原东北缘地区近期地壳水平运动速度场图像。水平运动速率、跨主要活动断裂GPS运动剖面以及应变率场结果表明：1）祁连山北缘断裂东段-榆木山断裂、六盘山断裂地壳缩短较为明显,但在断裂两侧邻近区域差异性运动并不明显,说明这两条断裂处于应变积累阶段,闭锁程度高;2）岷县-宕昌断裂处于剪切应变积累的强闭锁阶段,2013-07-22在该断裂带上发生了Ms6.6地震;3）受2008年汶川地震震后影响的龙门山震区已基本调整恢复到震前的运动态势,龙门山断裂带挤压缩短率为1-3 mm/a。The horizontal velocity field of the northeastern Qinghai-Tibet plateau is acquired by using the GPS data observed between 2011 and 2013. The current crustal movement in the northeastern margin of the Tibetan plateau is consistent with the long term motion. The north Qilianshan fault is experiencing the deformation of contraction and left-lateral shear, and the shortening rate is larger than the strike slip rate. The horizontal shortening rate of west part of north Qilianshan fault is larger than that of the east part. The GPS velocity profile across the west part of north Qilianshan fault shows that the strain is accumulating while the underneath of this fault is locking. The profile perpendicular to the Liupanshan fault demonstrates that the shortening is distributed at the west of Liupanshan with a range of 300 kmn. There is no differential movement in the vicinity of both sides of Liupanshan. Therefore, Liupanshan fault is locked deeply. The profile parallel to Diebu-Bailongjiang fault and west Qinling shows that there is a strike-slip deformation gradient between them. Linxia-Tanchang fault is located at this gradient and the shear strain is accumulating. The 2013 Minxian Ms 6.6 earthquake might be associated with this elastic strain accumulation due to locking. The tectonic motion of Longmenshan fault and surrounding area has been basically restored to horizontal movement before the 2008 Wenchuan earthquake.

关 键 词：青藏高原东北缘 地壳运动 水平速度场 岷县地震 地壳缩短 

分 类 号：P227[天文地球—大地测量学与测量工程]