位场梯度模法及其在碳酸盐岩地区断裂识别中的应用

Determination of faults using gradient modules of potential field anomalies and its application to carbonate rock area of South China

本文介绍了一种利用位场梯度模识别断裂位置的方法.利用余弦变换在位场转换中快速计算的优势在波数域计算异常各分量导数,从而在测量面或下延深度面可快速计算出位场梯度模,对位场梯度模设立阈值,压制无效梯度模值,放大有效梯度模值,自动搜索追踪边界位置,能增加断裂识别的准确性.通过模型试验,证明了这种效果.利用这种方法,计算了南方某碳酸盐岩地区的基底磁异常梯度模,识别出了该区的主要断裂分布.

In this article, a method to determine faults using gradient modules of potential field anomalies is introduced. We make use of advantage of fast calculation of Fast Discrete Cosine Transform to calculate each component＇s derivative in wave member domain. Therefore, gradient modules of the potential field on a measurement plane or some depth plane of downward continuation can be acquired. For gradient modules of the potential field, we give a threshold value, restrain useless gradient modules value and enhance approved gradient modules value . So faults can he plotted more properly and determined by means of the automated detections of the proper maximal locations. The modeling test proves good results based on the method we have discussed. Using this method, we determine the location of main fault distribution in a carbonate rock area in South China.