时变重力测量确定青藏高原地壳隆升与增厚速率

Determination of Crust Uplifting and Thickening of Qinghai-Tibetan Plateau from Time-Variable Gravity Measurements

  • 摘要: 联合绝对重力和重力反演与气候实验卫星(gravity recovery and climate experiment,GRACE)重力多年观测数据,获得了青藏高原多个基准站区域的地壳垂直形变速率。研究结果表明,绝对重力呈明显的负变化,绝对重力和卫星重力的时变系统差也呈较一致的负值,鼎新(DXIN)、德令哈(DLHA)、西宁(XNIN)、拉萨(LHAS)和仲巴(XZZB)5个基准站的区域地壳垂直形变呈明显的隆升状态,即拉萨块体、祁连块体和阿拉善块体处于地壳隆升状态,隆升速率分别约为2.01±0.15 mm/a、1.88±0.19mm/a、1.91±0.10 mm/a。在印度板块和欧亚板块的双向挤压下,青藏高原的地壳在不断的隆升与增厚,平均隆升速率约为1.94±0.17 mm/a,平均增厚速率约为2.35±3.30 mm/a。

     

    Abstract: The crustal uplift and thickening of Qinghai-Tibetan plateau was determined by the combined use of long-term absolute gravity measurements and GRACE satellite gravity measurement data. The results show that the obvious negative gravity change rate was detected by absolute gravity measurements. The systematic difference of the gravity change rates between absolute gravity measurements and GRACE measurements was also negative as 5 base stations at Dingxin, Delingha, Xining, Lhas, and Zhongba which representing the Alxa, Qilian and Lhas blocks were all in a crustal uplift status. The rising rate can be estimated numerically, and the velocity of Lhasa, Qilian and Alxa block is about 2.01±0.15 mm/a、1.88±0.19 mm/a and 1.91±0.10 mm/a, the crustal uplifting of the whole Qinghai-Tibetan plateau is about 1.94±0.17 mm/a, and the thickening is about 2.35±3.30 mm/a caused by the collision between the Indian and the Asianplates in the double-direction.

     

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