# 1st Lamé parameter

Gabriel Lamé

The 1st Lamé parameter, sometimes called Lamé's first parameter, or lambda λ, is an elastic modulus. It is used extensively in quantitative seismic interpretation and rock physics. It was first described by the French mathematician, Gabriel Lamé (right).

## Other expressions

λ can also be expressed in terms of Young's modulus, E, and Poisson's ratio, ν:

${\displaystyle \lambda ={\frac {E\nu }{(1+\nu )(1-2\nu )}}}$

The simplest expression casts λ in terms of bulk modulus and shear modulus μ:

${\displaystyle \lambda =K-{\frac {2}{3}}\mu }$