Okada

Higher Edu - Research dev card
Development from the higher education and research community
  • Creation or important update: 04/03/11
  • Minor correction: 04/03/11
Keywords

Okada : surface deformation due to a finite rectangular source in elastic half-space [Okada, 1985]

This software was developed (or is under development) within the higher education and research community. Its stability can vary (see fields below) and its working state is not guaranteed.
  • Web site
  • System: UNIX-like, Windows, MacOS X
  • License(s): BSD
  • Status: stable release
  • Support: maintained, no ongoing development
  • Designer(s): François Beauducel
  • Contact designer(s): beauducel_@_ipgp.fr
  • Laboratory, service: IPGP

 

General software features

The Okada [1985] model calculates analytical solution for surface deformation due to shear and tensile faults in an elastic half-space. Given rectangular fault geometry (length, width, depth, strike, dip) and 3-component dislocation amplitude (shear and tensile), it computes the displacements, tilt and horizontal strain at the free-surface.

The proposed Matlab script is a literal transcription of the Okada's equations, except that it proposes a strike angle of the fault. Dislocation parameters are given by: rake, slip and opening (instead of U1, U2, U3), following Aki & Richards [1980] definition, and (x,y) coordinates are relative to fault centroid. Lamé's constants λ and μ are also replaced by Poisson's ratio ν, since the equations are independent of other elastic parameters.

All the equations have been vectorized relative to coordinates (x,y) which can be for instance a meshgrid output.

See help for syntax, and script comments for details.

Context in which the software is used

This model is widely used in Earth Sciences to simulate ground deformation produced by local perturbation like tectonic faults (for earthquakes deformation or tsunami source) or volcanic dykes (magmatic intrusion at depth).

Publications related to the software

Okada Y., Surface deformation due to shear and tensile faults in a half-space, Bull. Seismol. Soc. Am., 75:4, 1135-1154, 1985.

Aki K., and P. G. Richards, Quantitative seismology, Freemann & Co, New York, 1980.