Dictionary:Percent frequency effect (PFE)

{{#category_index:P|percent frequency effect (PFE)}} 1. The basic polarization parameter measured in frequency-domain resistivity surveys, being the percent difference in apparent resistivity measured at two frequencies:

$PFE=100{\tfrac {(\rho _{dc}-\rho _{ac})}{\rho _{ac}}}$

where $\rho _{dc}$ and $\rho _{ac}$ are the low- and high-frequency apparent resistivities.

2. Decade-normalized PFE is multiplied by the log of the frequency ratio:

$PFE=[100{\tfrac {(\rho _{dc}-\rho _{ac})}{\rho _{ac}}}]log_{10}({\frac {f_{ac}}{f_{dc}}})$

3. Keller suggests that PFE be defined as:

$PFE=100{\tfrac {(\rho _{2}-\rho _{1})}{\sqrt {\rho _{1}\rho _{2}}}}$

where ρ₁ and ρ₂ are apparent resistivities measured at two frequencies that are a factor of 10 apart.