LMR

The equations that underlie the so-called LMR method, popularized by Bill Goodway, convert P-impedance and S-impedance into ${\displaystyle \lambda \rho }$ and ${\displaystyle \mu \rho }$.
${\displaystyle \lambda \rho =I_{P}^{2}-2I_{S}^{2}}$
${\displaystyle \mu \rho =I_{S}^{2}}$
where ${\displaystyle \lambda }$ is the first Lame parameter, ${\displaystyle \mu }$ is the second Lame parameter, and ${\displaystyle \rho }$ is bulk density. ${\displaystyle I_{P}}$ and ${\displaystyle I_{S}}$ are P- and S-impedance, respectively.