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Assessing the effect of upward continuation height on noise suppression and edge delineation in potential field data: Application to the Tarija basin, South America.

PrasadKND,OliveiraSP,GhomsiFEK,PhamLT.

EARTH SCIENCE INFORMATICS

https://doi.org/10.1007/s12145-026-02163-1 

In this study, we investigated the effect of the upward continuation height on the noise reduction and edge enhancement using the ETAHG filter. Synthetic examples show that very low continuation heights retain significant noise, whereas excessive continuation heights suppress short-wavelength anomalies, leaving only broad regional features and making individual source boundaries difficult to distinguish. The findings showed that the continuation height for gravity data is recommended not to exceed five grid intervals, while for magnetic data, which commonly exhibit higher anomaly resolution, the limit should remain under ten grid intervals. Our analysis also showed that the optimal continuation height can be identified at the point where the rate of spectral decay becomes significantly slower. The effectiveness of the upward continuation approach under realistic geological conditions is evaluated using the gravity data over Tarija basin, South America.

Choosing the right upward continuation height for gravity and magnetic data was largely empirical, often causing either excessive noise or loss of critical geological details. It is established scientifically validated continuation-height limits and identified a spectral-decay criterion to determine the optimal height for reliable edge enhancement. The findings improve the accuracy of geophysical interpretation, supporting better mineral exploration, groundwater investigations, and subsurface mapping for national resource management.

Fig: Natural logarithm of power spectra versus wavenumber of the Bouguer gravity data and its upward continuation fields, (b) ETAHG map and lineaments (red lines) inferred from the gravity anomaly continued at 3.6 km height overlaid by the major tectonic features of Tarija basin. The black color solid lines are the major thrust faults, solid green line is the P-Tr erosive limit and solid blue line is the Carboniferous erosive limit.

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