A heuristic method of removing micro-pulsations from airborne magnetic data

Abstract

An automatic, heuristic method has been developed for the removal of micro-pulsations from airborne magnetic data to improve the geological integrity of data. This method was applied to data collected in a high-sensitivity survey flown off the coast of Nova Scotia, Canada from September to October 2000. This method permitted the diurnal datameasured on land to be used to subtract micropulsation variations from the airborne data. Small differences in the variations are allowed between the data acquired at the base station and on the airborne platform. This is because conductivity contrasts between the land and sea water will change the amplitude and phase of the micropulsation. The new method adjusted the land based diurnal data to match the phase and amplitude of the micropulsation measured in the airborne data. This adjusted micropulsation was then removed from the data. This improved the final leveled data so that obvious micropulsations are not evident in the data. This noise reduction is critical, as any filtering which may be applied, cannot remove diurnal events from the airborne data without possibly removing geologic signal. The procedure will produce higher quality data that better show weaker features and patterns than the standard processing produces, such as subtraction of the base station data.