Magnetic Conversion Factors

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

Magnetic Conversion Factors
Quantity	cgs	SI	Conversion
Magnetic Field (B)	gauss (G)	tesla (T)	1 gauss = 10⁴T
Magnetic Field (B)	gamma ^a	nanotesla ^b (nT)	1 gamma ^a = 1 nT ^b
Field Intensity (H)	oersted (Oe)	A/m	1 oersted = 10³/4π A/m
Magnetization (M)	emu/cc	A/m	1 gauss = 10³ A/m
Susceptibility (% or S)	dimensionless		1 (cgs) = (1/4π)*(SI)
Koenigsberger ratio (Q)	dimensionless		1 (cgs) = 1 (SI)

*modified from Blakely (1995)

^a 1 gamma = 10^-5 gauss
^b 1 nanotesla = 10^-9 tesla
^c Also called emu/cc

Although susceptibility is dimensionless, it differs by a factor of 4π 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). GM-SYS Profile Modelling expects gammas (cgs) or A/m (SI).