中国及邻区岩石层大地水准面正演模拟

依据地震层析成像、地震测深和大地电磁测深结果给出的地球内部结构和物性分布 ,模拟了中国及邻区岩石圈中短波长大地水准面起伏。正演模拟结果显示 :地形起伏引起的大地水准面异常巨大 ,幅值变化可达 2 10 m,最大值在青藏高原 ,达 150余 m。沉积层底面起伏产生的大地水准面异常非常小 ,幅值只有 6.5m,表现出短波长特征。岩石层底面起伏产生的大地水准面异常极为平缓 ,约为 2 0 m。莫霍面产生的大地水准面异常形态与地形起伏引起的大地水准面异常形态相近 ,异常幅值只有后者的 2 / 3,在青藏高原只有后者的一半。岩石层内密度不均匀引起的大地水准面异常的幅值约为 75m。

THE SIMULATION OF LITHOSPHERIC GEOID IN CHINA AND ITS ADJACENT AREA

In this paper the geoid anomalies of middle short wavelength of China and its adjacent region are simulated on the basis of internal earth structure and distribution of density,which results from data of tomography,seismic sounding and telluric electromagnetic sounding.The simulation results show that the geoid anomaly casused by topography is much huge that its amplitude reaches 210 meters and the highest geoid anomaly,which is on the Tibet plateau, reaches over 150 meters.In the same time the geoid anomaly caused by sediment layer is very low,only 6.5 meters and shows short wave character. The Lithospheric geoid anomaly is about 20 meters. The form of the geoid anomaly caused by the Moho interface is similar to that of the topographic geoid anomaly,but the amplitude is less than the later by a factor of 1/3.The geoid anomaly caused by the uneveness of the lithospheric density is about 75 m.