Dear Matteo,

Please read equations 3 & 4 depicted in the text:

Another way to do the MT static shift correction is by converting TDEM data to an apparent resistivity curve then compare it with MT curve that shifted. The next step is to shift the TE curve and TM curve to match the TDEM curve.

This method is based on the relationship between TDEM diffusion depth and MT skin depth as shown below:

TDEM diffusion :  ∂ = 36 (ρ t)1/2 (3)

MT skin depth :  ∂’ = 603 (ρ T)1/2 (4)

Here T is the period (second) of MT and t is delay time of TDEM (millisecond). At the same depth of penetration we assume that TDEM delay time (t) will be equivalent with MT period (T). Then from the above equation we get the conversion factor: k = (t/T) = 195.

For more details, please see attached file.

Hoping this will be helpful,

Rafik

thank you so much Rafik, 

Matteo

Addition to previous answer, If you are interested in equivalence of MT and TEM recordings Pellerin and Hohmann (1990), Meju (2005) and references therein may help you.  

Emin

ibrary.seg.org/doi/abs/10.1190/1.1442716