Moho Depth Estimation Beneath Tibet From Satellite Gravity Data Based on a Condensation Approach
Moho Depth Estimation Beneath Tibet From Satellite Gravity Data Based on a Condensation Approach
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基于凝结法的卫星重力数据估计青藏高原以下莫霍面深度
DOI：
10.1029/2020ea001261
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发表时间：
2021
影响因子：
3.1
通讯作者：
Wang Bin
中科院分区：
文献类型：
--
作者：
Chen Wenjin;Tenzer Robert;Xu Xinyu;Wang Shuai;Wang Bin
我们开发了一种根据重力和重力梯度测量数据恢复莫霍面深度的算法，并应用该方法来估计青藏高原下方的莫霍面深度。该算法的基本思想是用凝结层相对于平均莫霍面深度的数学方式描述莫霍面深度波动，而不是应用更常用的等静压补偿方案。在谱域和空间域中导出了在功能上将重力场量与（莫霍面）凝结层联系起来的表达式。该算法的主要优点是重力场量与表面密度异常之间的函数关系以及因此莫霍面深度波动具有线性形式。使用卫星重力和重力梯度测量数据对所提出的算法进行了测试。基于应用该算法获得的莫霍面深度（相对于大地水准面）估计值与西藏研究区的全球和区域地震莫霍面结果进行了验证。我们还将结果与通过应用 Parker-Oldenburg 和 Vening Meinesz-Moritz (VMM) 方法获得的相应莫霍面深度估计进行比较。验证表明，三种重力方法的结果相似，并且与区域地震莫霍面模型非常吻合。尽管如此，VMM 方法和我们的算法在本次比较中优于 Parker-Oldenburg 方法。结果分析还表明，当应用于从重力梯度测量而不是重力数据进行莫霍面测定时，新开发的算法提供了更好的结果（就与区域地震莫霍面模型的均方根拟合而言）。
We develop an algorithm for a Moho depth recovery from gravity and gravity gradiometry data and apply this method to estimate the Moho depth beneath the Tibetan Plateau. The basic idea of this algorithm is to describe mathematically the Moho depth undulations in terms of a condensation layer with respect to a mean Moho depth, instead of applying more commonly used isostatic compensation schemes. Expressions that functionally relate gravity field quantities with a (Moho) condensation layer are derived in spectral and spatial domains. The main advantage of this algorithm is that a functional relation between gravity field quantities and surface density anomalies, and consequently Moho depth undulations, has a linear form. The proposed algorithm is tested using satellite gravity and gravity gradiometry data. The Moho depth (taken with respect to the geoid surface) estimates obtained based on applying this algorithm are validated against global and regional seismic Moho results at the study area of Tibet. We also compare the result with the corresponding Moho depth estimates obtained by applying the Parker–Oldenburg and Vening Meinesz–Moritz (VMM) methods. The validation shows that results from all three gravimetric methods are similar, and they also closely agree with a regional seismic Moho model. Nevertheless, the VMM method and our algorithm in this comparison overperform the Parker–Oldenburg's method. The analysis of results also reveals that the newly developed algorithm provides better result (in terms of the RMS fit with a regional seismic Moho model) when applied for a Moho determination from gravity gradiometry instead of gravity data.