bruges.rockphysics.moduli module

moduli.py

Converts between various acoustic/eslatic parameters, and provides a way to calculate all the elastic moduli from Vp, Vs, and rho.

Created June 2014, Matt Hall

Using equations http://www.subsurfwiki.org/wiki/Elastic_modulus from Mavko, G, T Mukerji and J Dvorkin (2003), The Rock Physics Handbook, Cambridge University Press.

bruges.rockphysics.moduli.bulk(vp=None, vs=None, rho=None, mu=None, lam=None, youngs=None, pr=None, pmod=None)[source]

Computes bulk modulus given either Vp, Vs, and rho, or any two elastic moduli (e.g. lambda and mu, or Young’s and P moduli). SI units only.

Parameters:
  • vs, and rho (vp,) –
  • any 2 from lam, mu, youngs, pr, and pmod (or) –
Returns:

Bulk modulus in pascals, Pa

bruges.rockphysics.moduli.lam(vp=None, vs=None, rho=None, pr=None, mu=None, youngs=None, bulk=None, pmod=None)[source]

Computes lambda given either Vp, Vs, and rho, or any two elastic moduli (e.g. bulk and mu, or Young’s and P moduli). SI units only.

Parameters:
  • vs, and rho (vp,) –
  • any 2 from bulk, mu, youngs, pr, and pmod (or) –
Returns:

Lambda in pascals, Pa

bruges.rockphysics.moduli.moduli_dict(vp, vs, rho)[source]

Computes elastic moduli given Vp, Vs, and rho. SI units only.

Parameters:Vs, and rho (Vp,) –
Returns:A dict of elastic moduli, plus P-wave impedance.
bruges.rockphysics.moduli.mu(vp=None, vs=None, rho=None, pr=None, lam=None, youngs=None, bulk=None, pmod=None)[source]

Computes shear modulus given either Vp, Vs, and rho, or any two elastic moduli (e.g. lambda and bulk, or Young’s and P moduli). SI units only.

Parameters:
  • vs, and rho (vp,) –
  • any 2 from lam, bulk, youngs, pr, and pmod (or) –
Returns:

Shear modulus in pascals, Pa

bruges.rockphysics.moduli.pmod(vp=None, vs=None, rho=None, pr=None, mu=None, lam=None, youngs=None, bulk=None)[source]

Computes P-wave modulus given either Vp, Vs, and rho, or any two elastic moduli (e.g. lambda and mu, or Young’s and bulk moduli). SI units only.

Parameters:
  • vs, and rho (vp,) –
  • any 2 from lam, mu, youngs, pr, and bulk (or) –
Returns:

P-wave modulus in pascals, Pa

bruges.rockphysics.moduli.pr(vp=None, vs=None, rho=None, mu=None, lam=None, youngs=None, bulk=None, pmod=None)[source]

Computes Poisson ratio given either Vp, Vs, and rho, or any two elastic moduli (e.g. lambda and mu, or Young’s and P moduli). SI units only.

Parameters:
  • vs, and rho (vp,) –
  • any 2 from lam, mu, youngs, bulk, and pmod (or) –
Returns:

Poisson’s ratio, dimensionless

bruges.rockphysics.moduli.vp(youngs=None, vs=None, rho=None, mu=None, lam=None, bulk=None, pr=None, pmod=None)[source]

Computes Vp given bulk density and any two elastic moduli (e.g. lambda and mu, or Young’s and P moduli). SI units only.

Parameters:
  • 2 from lam, mu, youngs, pr, pmod, bulk (Any) –
  • Rho
Returns:

Vp in m/s

bruges.rockphysics.moduli.vs(youngs=None, vp=None, rho=None, mu=None, lam=None, bulk=None, pr=None, pmod=None)[source]

Computes Vs given bulk density and shear modulus. SI units only.

Parameters:
  • Mu
  • Rho
Returns:

Vs in m/s

bruges.rockphysics.moduli.youngs(vp=None, vs=None, rho=None, mu=None, lam=None, bulk=None, pr=None, pmod=None)[source]

Computes Young’s modulus given either Vp, Vs, and rho, or any two elastic moduli (e.g. lambda and mu, or bulk and P moduli). SI units only.

Parameters:
  • vs, and rho (vp,) –
  • any 2 from lam, mu, bulk, pr, and pmod (or) –
Returns:

Young’s modulus in pascals, Pa