地震研究

首先研究了大型沉积盆地对地表重力异常的影响,然后基于Parker-Oldenburg迭代算法,利用经过沉积层改正的布格重力异常数据反演了中国西部的Moho面深度。结果表明,地壳浅层密度异常对地表重力异常和Moho面深度结果的影响较大,利用简化的三层沉积层模型,计算出的中国西部沉积盆地的重力异常改正最大可达25 mGal,由此引起的Moho面深度可达2.2 km,Moho面深度最终计算结果与区域最新研究成果相符合,因此,利用重力异常反演Moho面深度时,应考虑沉积层的影响以提高反演精度。

Firstly,the influence of the huge sedimentary basin on the surface gravity anomaly was studied. Secondly,based on the Parker-Oldenburg iterative algorithm,we inversed the depth of Moho surface in Western China by using the Bouguer gravity anomaly data after the correction of the sedimentary. The results show that the shallow density anomaly in the crust had the great influence on both surface gravity anomaly and the depth of Moho surface. Using the simplified 3-layers sedimentary model,we obtained that the gravity anomaly correction can be up to 25 mGal in the sedimentary basin in Western China,which induced the depth of Moho surface is 2.2 km,and the calculated depth of Moho surface is corresponding to the latest regional research result. In order to get better accuracy of the depth of Moho surface,the sedimentary effects should be considered in the process of inversing the depth of Moho surface by using gravity anomaly.

引言
1 中国西部沉积层盆地重力异常改正
2 中国西部的新布格重力异常
3 中国西部Moho面深度的反演
4 结论

图1 密度异常体埋深与地表重力异常的关系<br/>Fig.1 The relationship between the buried depth of density anomaly body and gravity anomaly in surface

图1 密度异常体埋深与地表重力异常的关系
Fig.1 The relationship between the buried depth of density anomaly body and gravity anomaly in surface

图2 中国西部沉积层厚度(a)及沉积层引起的重力异常改正(b)<br/>Fig.2 The thickness of sedimentary layer(a)and the gravity anomly correction caused by sedimentary layer(b)in western China

图2 中国西部沉积层厚度(a)及沉积层引起的重力异常改正(b)
Fig.2 The thickness of sedimentary layer(a)and the gravity anomly correction caused by sedimentary layer(b)in western China

图3 中国西部的区域地形(a)、自由空气异常(b)、布格重力异常(c)以及去除沉积层效应的布格异常(d)<br/>Fig.3 The regional topography(a),free-air anomaly(b),bouguer gravity anomaly(c)and bouguer gravity anomaly after rejecting the effect of sedimentary layer(d)in western China

图3 中国西部的区域地形(a)、自由空气异常(b)、布格重力异常(c)以及去除沉积层效应的布格异常(d)
Fig.3 The regional topography(a),free-air anomaly(b),bouguer gravity anomaly(c)and bouguer gravity anomaly after rejecting the effect of sedimentary layer(d)in western China

图4 中国西部Moho面深度结果(a)及沉积层效应引起的Moho面深度(b)<br/>Fig.4 The result of Moho depth(a)and the Moho depth disturbed by sedimentary layer effects(b)in Western China

图4 中国西部Moho面深度结果(a)及沉积层效应引起的Moho面深度(b)
Fig.4 The result of Moho depth(a)and the Moho depth disturbed by sedimentary layer effects(b)in Western China

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备注

引言

1 中国西部沉积层盆地重力异常改正

2 中国西部的新布格重力异常

3 中国西部Moho面深度的反演

4 结论

期刊信息