Gravity and magnetic methods - Geophysics for the Mineral Exploration Geoscientist - page 111

a)

180°W
90°N

120°W 60°W 0° 60°E 120°E 180°E

60°N

30°N

30,000

00°

30°S

30,000

60°S

90°S

b)

180°W 120°W 60°W 0° 60°E 120°E 180°E

90°N

+80

60°N

30°N

0°

30°S

-80

-60

60°S

90°S

c)

180°W 120°W 60°W 0° 60°E 120°E 180°E

90°N

-60 -40

NP

40

MNP

GNP

60°N

30°N

0°

30°S

MSP +40

60°S

SP

GSP

90°S

Figure 3.21 The International Geomagnetic Reference Field (2004). (a) Intensity (nT), (b) inclination (degrees), and (c) declination (degrees).
GNP - geomagnetic north pole, GSP - geomagnetic south pole, ME - magnetic equator, MNP - magnetic north pole, MSP - magnetic

south pole, NP - north geographic pole, and SP - south geographic pole.