## Magnetic Conversion Factors

To convert from SI units to cgs units for use in GM-SYS, use the conversion table below. For example, divide magnetization reported in A/m by 10³ for input into GM-SYS.

Conversion Factors
Quantity cgs unit SI Unit Conversion
Magnetic field (B) gauss (G) tesla (T) 1 gauss=0.0001 T
" gamma  nanotesla (nT)  1 gamma  = 1 nT 
Field intensity (H) oersted (Oe)A/m 1 oersted = 10³ / 4 A/m
Magnetization (M) gauss  (G) A/m 1 gauss  = 10³ A/m
Susceptibility ( or S) dimensionless dimensionless 1 (cgs) = 4 (SI)
Koenigsberger ratio (Q) dimensionless dimensionless 1 (cgs) = 1 (SI)
 1 gamma = 10-5 gauss
 1 nanotesla = 10-9 tesla
 Also called emu/cm³.
modified from Blakely (1995)

Notes:

• Although susceptibility is dimensionless, it differs by a factor of 4 between the two systems.
• The defining equations above require Earth magnetic field values to be given in oersted (cgs) or A/m (SI). However in the geophysical literature, Earth magnetic field values are commonly given in gammas (cgs) or nanotesla (SI) which is what GM-SYS expects.