Prediction of gravity anomalies for geophysical exploration

T.O Idowu

doi:10.4314/fje.v1i1.50776

Abstract

Interpretation of gravity anomalies (determined on the earth’s surface) reveals information on mineral resources beneath the earth. The density of gravity stations (where gravity anomalies are determined) is critical to the successful interpretation of these anomalies. Where the density of the available gravity anomalies is not enough, for a particular purpose of geophysical exploration, more gravity stations can be established within the surveyed area and the gravity anomalies observed for these stations. In some cases, where observations of gravity anomalies are not possible due, probably, to inaccessibility of the newly chosen gravity stations, the required gravity anomalies for such stations can be estimated (predicted). Currently, classical least squares technique is used to accomplish such task. However, the technique does not produce optimum results because its formulation assumes that the observed gravity anomalies, used for the prediction, are error free, whereas, all observed quantities are affected by random errors. Therefore, in this study, an attempt is made to carry out prediction of gravity anomalies for geophysical exploration using least squares collocation technique. This is considered to be a better alternative because its formulation takes the presence of random errors of observations in the observed quantities into consideration and makes provision for filtering out these errors while predicting the signals of interest at the required number of stations.

Highlights

The search for mineral resources represents the major geophysical exploration activity in the world today
Mineral resources can be described as beneficial subsurface features whose natural habitat is the earth
In the early years of twentieth century, the continued efforts by explorers to look for more effective, less risky and more economical technique of sub-surface exploration led to the advent of geophysical exploration

Summary

Introduction

The search for mineral resources represents the major geophysical exploration activity in the world today. This is because mineral resources are the concealed subsurface geological features of most economic interest to many countries of the world. Mineral resources can be described as beneficial subsurface features whose natural habitat is the earth. They include solid metallic minerals such as, iron ore, zinc etc, solid non-metallic minerals like limestone, marble etc., liquid minerals such as oil, water etc., and gaseous minerals like gasses in buried cavity. Its method had been only drilling using percussion bits This had posed a lot of risk as explorer could and ignorantly get exposed to dangerous materials underground. In the early years of twentieth century, the continued efforts by explorers to look for more effective, less risky and more economical technique of sub-surface exploration led to the advent of geophysical exploration

Methods

Results

Conclusion