Reduced ice mass loss and three-dimensional viscoelastic deformation in northern Antarctic Peninsula inferred from GPS
Reduced ice mass loss and three-dimensional viscoelastic deformation in northern Antarctic Peninsula inferred from GPS
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DOI：
10.1093/gji/ggaa229
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发表时间：
2020-08
影响因子：
2.8
通讯作者：
N. Samrat;Matt A. King;C. Watson;A. Hooper;Xianyao Chen;V. Barletta;A. Bordoni
中科院分区：
文献类型：
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作者：
N. Samrat;Matt A. King;C. Watson;A. Hooper;Xianyao Chen;V. Barletta;A. Bordoni
我们考虑了南极半岛下固体地球由于拉森B冰架破裂后开始的冰质量损失而产生的粘弹流变学。我们扩展了以前的分析附近的连续GPS时间序列，包括额外的五年和额外的考虑水平分量的变形。它们显示出从2002年到2011年的强烈抬升，随后到2018年的抬升速率降低。模拟GPS派生的隆起作为一个粘弹性响应正在进行的区域冰卸载从一个新的冰模型证实了较早的估计，低上地幔粘度为0.3-3 × 1018 Pa·s，在这个地区，但允许弹性岩石圈厚度的范围很广。观测和模拟的北坐标分量显示出很小的非线性变化，由于位置的冰块变化的GPS站点的东部。然而，观察到的和模拟的东部坐标分量的比较将上地幔粘度限制在小于1.9 × 1018 Pa·s，这与单独由隆升速率提出的粘度范围一致，并为该结果提供了重要的、基本上独立的证实。我们的水平分析表明，只有边际敏感性模拟岩石圈厚度。水平分量的结果对所采用的板块旋转模型敏感，基于ITRF 2014的估计表明，东部分量的剩余板块运动和2002年前冰川均衡调整的总和可能小于0.5 ±0.5毫米/年。
We consider the viscoelastic rheology of the solid Earth under the Antarctic Peninsula due to ice mass loss that commenced after the breakup of the Larsen-B ice shelf. We extend the previous analysis of nearby continuous GPS time-series to include five additional years and the additional consideration of the horizontal components of deformation. They show strong uplift from ∼2002 to 2011 followed by reduced uplift rates to 2018. Modelling the GPS-derived uplift as a viscoelastic response to ongoing regional ice unloading from a new ice model confirms earlier estimates of low upper-mantle viscosities of ∼0.3–3 × 1018 Pa s in this region but allows a wide range of elastic lithosphere thickness. The observed and modelled north coordinate component shows little nonlinear variation due to the location of ice mass change to the east of the GPS sites. However, comparison of the observed and modelled east coordinate component constrains the upper-mantle viscosity to be less than ∼9 × 1018 Pa s, consistent with the viscosity range suggested by the uplift rates alone and providing important, largely independent, confirmation of that result. Our horizontal analysis showed only marginal sensitivity to modelled lithospheric thickness. The results for the horizontal components are sensitive to the adopted plate rotation model, with the estimate based on ITRF2014 suggesting that the sum of residual plate motion and pre-2002 glacial isostatic adjustment is likely less than ∼±0.5 mm yr−1 in the east component.