鄂尔多斯地块及邻区重力均衡研究

为更加精细地了解鄂尔多斯及其邻区的地壳均衡状态，本文在考虑地壳密度横向变化的基础上计算了该区域的重力均衡异常。首先，利用研究区内重力异常和真实莫霍面深度进行反演得到壳幔密度差分布，以艾里均衡理论为基础计算了莫霍面的理论深度；其次，通过莫霍深度理论值与真实值对比来获得研究区的重力均衡异常；最后，结合区内地震分布，讨论了重力均衡异常与地震活动的关系。结果表明:研究区内盆地以负均衡异常为主，山地则表现为正均衡异常，鄂尔多斯地块内部基本均衡；研究区内中强地震主要分布在重力均衡异常梯度带上。 

Gravity isostaty of Ordos block and its surrounding regions

In order to better understand the isostasy of the crust beneath Ordos block and its surrounding regions, we take into account laterally variation of crustal density in the calculation of isostaty anomalies. Firstly, obtained by the inversion for regional gravity anomaly and Moho depth when calculating the isostasy anomaly; Secondly, we compared theoretical Moho depth and real one which is inverted from the receiver function so as to get the crustal isostasy in the studied regions. Finally, we discussed the relationship between the isostatic gravity anomaly and distribution of earthquakes in this region. The results indicate that the negative isostatic anomaly mainly corresponds to basins, and positive anomaly to mountainous regions, therefore the interior of Ordos block is basically in isostatic state. Moreover, the most major earthquakes mainly occurred on the isostatic anomaly gradient belt in the studied region.