High-Resolution AeroMagnetic (HRAM) data 

Example 1 – The effect of increased flight line density on magnetic data quality for interpretation

The example shows four separate images of the total magnetic field over the same area of the Canadian shield, near La Ronge, Saskatchewan (data courtesy of Fugro Airborne). Each image is created by first decimating the line spacing in the data to 200m, 400m, 800m, and 1600m, respectively. In every case the flight height and sample spacing along-line remain constant.

[click to enlarge]

The dramatic increase in resolution of geologic features with decreasing flight line separation shows how important the sampling interval (i.e. flight line separation) is to the interpretability of aeromagnetic data. If the sampling interval is significantly larger than the magnetic feature under investigation then much of the higher frequency information is lost. Likewise, if the sampling interval along line (station interval or sampling rate) is much higher frequency than the line spacing, then the data acquires a strong ‘aliasing’ quality to it. Anomalies measured along a single flight line are extrapolated perpendicular to the flight line direction. In this example, note the occurrence in the 1600m line spacing image of anomalies elongated NW-SE, perpendicular to the flight line direction which is NE-SW.

If surveys are designed to image sedimentary anomalies such as faults, stratigraphy, and channels, then the flight line spacing should be significantly smaller than the scale of the feature under investigation.

Example 2 – The power of HRAM data vs. non-HRAM for mapping in sedimentary rocks.

Example 3 – The causes of magnetic anomalies within the sedimentary section

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