Page 12 - Marine Magnetometer Processing

Figure 6: Time-series plots showing a number of anomalies caused by different objects We can see the effect of a magnetic object on the Earth’s magnetic field in figure 7. With no magnetic objects in the area the magnetic field would be the same value everywhere and the magnetometer reports the same value for magnetic field strength. The red flux lines in figure 7 represent the magnetic field and the strength of that field at a point is shown by the distance between each line; the closer the lines are together the stronger the magnetic field is reported by the magnetometer passing through it. Placing a magnetic object within the area distorts or bends the field making some lines move further apart while others go closer together. As the magnetometer is towed over the site it passes through areas where the flux lines are different distances apart and hence it records Marine Magnetometer Processing \[11\] © 3H Consulting Ltd Figure 7: Distortion of the Earth's magnetic field along the yellow line, shown as a TS plot (above) and red magnetic flux lines (below)