用变密度模型反演青藏高原的莫霍面深度

Moho Depths Inversion of Qinghai-Tibet Plateau with Variable Density Model

采用密度随深度呈指数变化的变密度模型来反演莫霍面深度,给出了利用指数密度模型在波数域中计算重力异常的正演公式及界面深度的反演公式。结果表明,青藏高原莫霍面呈现出边缘浅、中部深,边缘变化快、梯度大,中间变化梯度趋缓的特点。通过对常密度模型、变密度模型及地震反演得到的莫霍面的比较,证实变密度模型更适合于莫霍面结构的反演。

A variable density model with exponential density contrast is used for inverting Moho depths instead of constant density model. The method is introduced and some formulae are derived. The Moho depths of Qinghai Tibet plateau are inversed from gravity data with exponential density model. The inversion results demonstrate that the Moho depths of Qinghal-Tibet plateau are shallow around the edges, and deep at the center. The gradients at the edges are steeper than at the center. The variable density model is more suitable for inversion with Moho depths structures than constant density model by comparison of Moho depth from seismic inversion.