The Moho interface depths and variations provide important references to understanding the outward growth and expansion mechanisms of the Tibetan Plateau, which have drawn much attention. Here, we constrain the Moho variations beneath the northeastern Tibetan Plateau (NETP) by using multiple geodetic data and climate models. Hydrological and tectonic gravitational signals are identified from multisource data and removed from the satellite gravity observations. Moreover, the mass variation rate, resulting from vertical Moho changes is calculated. The result shows that the mass variation rate due to the Moho changes is 1.3 ± 0.6 mm/yr (equivalent water height) within the NETP, which corresponds to a Moho uplift rate of 2.7 ± 1.3 mm/yr. Additionally, we calculate the tectonic Earth surface uplift rate from GPS and leveling observations with loading and GIA (glacier isostatic adjustment) influence corrected, which gives an uplift rate of 2.2 ± 0.1 mm/yr and is similar with the Moho uplift rate. Our results indicate that the crust in the NETP is uplifted with a slight decrease in crustal thickness. Combined with the lithospheric structure from seismological tomography studies, we suggest that the crustal uplift of the NETP is mainly caused by isostatic adjustment since the delamination of the thickened lithosphere.

中文翻译：

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多大地数据揭示青藏高原东北部莫霍面变化

莫霍面界面深度和变化为理解青藏高原向外生长和扩张机制提供了重要参考，引起了广泛关注。在这里，我们通过使用多个大地测量数据和气候模型来限制青藏高原东北部 (NETP) 下的莫霍面变化。从多源数据中识别出水文和构造引力信号，并从卫星重力观测中去除。此外，还计算了由垂直莫霍面变化引起的质量变化率。结果表明，NETP 内由莫霍面变化引起的质量变化率为 1.3 ± 0.6 mm/yr（等效水高），这对应于 2.7 ± 1.3 mm/yr 的莫霍面抬升速率。此外，我们根据 GPS 和校正加载和 GIA（冰川均衡调整）影响的水平观测计算构造地球表面抬升率，其抬升率为 2.2 ± 0.1 毫米/年，与莫霍面抬升率相似。我们的结果表明，NETP中的地壳被隆起，地壳厚度略有减少。结合地震层析成像研究的岩石圈结构，我们认为NETP的地壳隆升主要是由于加厚的岩石圈分层后的均衡调整引起的。