扩边尺度对重力异常分层分离处理的影响——以插值切割法为例

The Effects of Expanding Edge Length in the Processing of Gravity Anomalies Separation:An Example of Interpolation Cut Method

以插值切割法为例,对理想模型在地表的重力异常数据进行不同尺度的扩边,并对扩边后的数据进行不同深度层源的切割分离。基于分离后的结果,从不同扩边尺度、不同深度层源的重力异常差异、扩边尺度与重力场源分离误差的角度研究扩边尺度对重力异常分层分离处理的影响。结果表明:1)理想模型数据区域的边界效应与扩边尺度、切割分离深度、异常的规模和幅度及空间位置等因素相关;2)扩边尺度的选择应综合考虑分析资料所需满足的精度和数据计算效率,扩边尺度不宜过大,扩边尺度与重力异常分层分离最大切割深度至少应满足2∶1的要求才能明显改善边界效应,对含有较大重力异常边界进行切割分离时,应在2倍扩边尺度的基础上再进一步扩边;3)边界效应的空间展布不是由数据区域边界向中心区域均匀分布,而与异常体的规模和空间位置有关。

Using interpolation cut method, the expanded gravity anomalies of ideal model on the surface at different scales is separated into several gravity anomalies caused by strata at different depths. Based on separated results, the effects of expanding edge length on gravity anomalies separation are studied from two aspects: the difference of gravity anomalies at different scales and depths, and the mean square deviation between the expanding edge scale and the gravity anomalies separation. The results show that 1) The region boundary effect of ideal model data is related to the expanding edge length, the depth of cutting separation, location, scale and intensity of geological abnormal bodies. 2) In selecting the expanding edge scale, accuracy and computational efficiency should be taken into consideration. The expanded edge size should not be too large, and the expanded edge size and maximum cutting depth for gravity anomalies separation should at least meet the requirements of 2∶1;this significantly improves the boundary effect. When cutting and separating the boundary with large gravity anomalies,it is necessary to further expand the boundary on the basis of twice the scale of expansion. 3) The spatial distribution of the boundary effect is not evenly distributed from the boundary of the data area to the central area, but is related to the scale and spatial location of the anomalous body.