Name of program: GNStress

Type of program (eg quake model, mesh generator, strain calculator, visualizer, etc):

Model stresses induced by faulting, for studying fault interactions.

Author: Russell Robinson; uses some code of Okada (1992) -- "Russell Robinson" <.R.Robinson@gns.cri.nz>.

Institution: Institute of Geological & Nuclear Sciences

Program's heritage (ie name and author of predecessor code if any):

Actively being further developed (y/n): Yes

Language: Visual Basic, Fortran

2d (y/n): N

3d (y/n): Y

Elastic full space (y/n): N

Elastic half space (y/n): Y

Layered elastic (y/n): N

Viscoelastic half space (y/n): N

Layered viscoelastic (y/n): N

Maximum number of faults: No limit

Forward model (y/n):Y

Inversion capability (y/n): N

Type of inversion:

Finite element ability (y/n): N

Boundary constraints:

Automatic mesh generation:

Includes self gravitation (y/n): N

Quasi-static failure criteria (y/n): N

User defined failure criteria (y/n): N

Hardwired failure criteria (eg Coulomb): Coulomb

Dynamic solution (y/n): N

Includes waves (y/n): N

Highest resolved frequency:

Includes inertia (y/n): N

Are there accompanying utilities (y/n): N

Is it one main program or several programs that communicate via scripts, files, and pipes? Main program plus 2 dynamic link libraries; Multi-threaded.

If it is several programs, please give a 1 line description of the major players.

Input format description: Fill in interactive text boxes

Output format description: Bitmap files and/or ascii data files (output format described in an included text file)

Is this code available to interested researchers (y/n): Y

Executable available (y/n): Y, via ftp: ftp.gns.cri.nz, directory pub/robinson, file GNSetup.exe.

Type of machine: Windows PC

Source available (y/n): N

Please describe what you consider to be the important features of this code in a paragraph or two.

GNStress uses an interactive user interface to input data, and provides a colorful output display of whatever stress field is selected (saved as a bitmap file). Output can also be written to a disk file for processing by other programs. The user specifies the number of faults, their geometric properties and slip distributions, and a regional stress field. Output is the induced stress plus the regional stress expressed as the "Coulomb failure stress", either on faults of the same orientation, on optimally oriented faults, or on faults of any specified orientation. Results can be map view, cross- section, or projected onto a specified fault plane.

References describing the algorithms or results from use:

Robinson, R. and P. McGinty, submitted 1999. The Enigma of the Arthur's Pass, New Zealand Earthquakes,2: The Aftershock Distribution and Its Relation to Regional and Induced Stress Fields. Jl. Geophys. Res.