Studying the theoretical basis and advantages and disadvantages of Logistic methods of the total horizontal Gradient

Abstract

Edge detection is one of the most important steps in interpretation of
magnetic and gravity data. In magnetic and gravity maps, it is difficult to
distinguish adjacent sources due to their field superposition. Many
different techniques have been used to determine the edges of sources.
These techniques are based on vertical or horizontal gradients of
magnetic and gravity data or combinations of them, and the edges of the
geological structures are determined by maximum, minimum, or zero
values in the output maps. One of the most popular techniques is the total
horizontal gradient which is based on horizontal gradients of magnetic
and gravity data. The capability of the total horizontal gradient technique
in mapping the boundaries of deep bodies is very limited when competing
with large-amplitude shallow bodies. Some enhanced modifications of the
total horizontal gradient technique have been introduced to improve the
boundary estimation results. These techniques are based on logistic
functions and derivatives of the total horizontal gradient. In this study, we
aim to estimate the effectiveness of the logistic filters of the total
horizontal gradient. To obtain optimum results, these filters were tested
on synthetic gravity and magnetic data and real magnetic data from the
Zhurihe region (China). The findings show that the logistic filters can
provide more accurate and sharper boundaries without false source edges
than the total horizontal gradient. These techniques can determine the
edges of shallow and deep structures at the same time. These results
demonstrate that the logistic filters are useful tools for the qualitative
interpretation of potential field data