Gravity derived Moho for South America
Gravity derived Moho for South America
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DOI：
10.1016/j.tecto.2013.03.023
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发表时间：
2013-12
期刊：
影响因子：
2.9
通讯作者：
M. Meijde;J. Julià;M. Assumpção
中科院分区：
文献类型：
--
作者：
M. Meijde;J. Julià;M. Assumpção
南美洲的地壳结构是地球大陆地区中了解最少的地区之一。由于整个南美洲的地壳厚度估计很少或分布不均，大陆大部分地区的地壳厚度变化仍然没有得到很好的限制。为了解决这一稀缺和不均匀的数据覆盖，我们探讨了从卫星重力数据推导地壳厚度的可能性。在这项研究中，我们使用的组合重力模型EIGEN-6C，这是由GOCE和其他重力数据。重力场和稳态海洋环流探测器（GOCE）卫星的空间分辨率比南美洲任何陆基重力或地震勘探都均匀得多。重力数据反演是一个简单的两层模型，在界面上，莫霍面上的密度对比是固定的。该方法不依赖于点约束数据，并假设所有的信号都与莫霍面的地形有关。因此，可以通过与地壳厚度的点观测进行比较来评估模型的质量。我们表明，对于大陆的稳定部分，90%的估计是相似的，在误差范围内，地震观测。变化发生在活动造山带或怀疑非标准莫霍面密度对比的地区。与地震学模型的比较表明，与最近的模型高度相关。特别是在地壳结构的大陆和全球模型在波路径或点约束方面有局限性的地区，基于重力的模型提供了地壳结构的独特连续性，提供了对结构和构造的新见解，并增加了我们对南美洲下方地球结构的理解。
Crustal structure in South America is one of the least understood among the Earth's continental areas. Variations in crustal thickness are still poorly constrained over large portions of the continent because of scarce or unevenly distributed crustal thickness estimates throughout South America. To address this scarce and inhomogeneous data cover we explore the possibility to derive crustal thickness from satellite gravity data. In this study, we utilize the combined gravity model EIGEN-6C, which is composed of GOCE and other gravity data. The Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite has a much more uniform spatial resolution than any land-based gravity or seismic survey in South America. The gravity data inversion is for a simple two-layer model with fixed density contrast over the interface, the Moho. The method is not relying on point constraint data and assumes that all of the signal is related to topography of the Moho. Model quality can therefore be assessed by a comparison with point observations on crustal thickness. We show that for the stable part of the continent 90% of our estimates are similar, within error bounds, to seismic observations. Variations occur in active orogenic zones or regions with suspected non-standard Moho density contrasts. A comparison with seismological models shows a high correlation with the most recent model. Especially in areas where continental and global models of crustal structure have limitations in terms of wave paths or point constraints the gravity based model provides a unique continuity of crustal structure providing new insights on structure and tectonics and increase our understanding of the Earth's structure underneath South America.