基于重力数据反演南海及邻区莫霍面深度分布特征

Moho Depths of the South China Sea and Adjacent Regions: Results from Gravity Anomaly Data

采用重力异常数据,在频率域内通过Parker-Oldenburg反演算法计算南海及邻区的莫霍面深度。通过EGM2008重力场模型联合GOCE重力场模型,计算研究区的自由空气重力异常;通过重力场分离,得到莫霍面起伏引起的重力异常,用于反演莫霍面深度。计算结果与地震剖面计算的莫霍面深度结果平均偏差1.59 km,标准偏差1.9 km。结果表明,南海及邻区的莫霍面深度分布具有明显的区域化构造特征。

Gravity inversion can be used to determine Moho depths in sea regions where we lack adequate seismic information.In this study,the gravity anomaly is used to calculate the Moho depths of the South China Sea and adjacent regions.After isolating the gravity anomaly of Moho depths from the free-air gravity anomalies,the resulting gravity residual is used to invert the Moho depths based on Parker-Oldenburg inversion algorithm.To eliminate the high-frequency oscillations that occured in the inversion process,a cosine filter for gravity data filtering in wave number domain is applied,where smaller and greater frequency parameters are estimated from the energy spectrum of the residual gravity anomaly.The average difference in Moho depths between this study and the seismic measurement results is 1.59 km,the standard deviation is 1.9 km.The results show that the Moho depths in the study regions show the obvious regional tectonic features.