- len (data for packages FORMS, MODEL, CRT, NET)
**Model with a lenticular inclusion.**

*Examples:*

VRML view of velocities, interfaces, rays and wavefronts.

2-D colour plots of velocities.

Velocity isolines in 2-D sections.

3-D two-point ray tracing for point source, plane wave incident at the bottom of the model and for exploding reflector.

3-D interpolation of travel times within ray cells.

First-arrival travel times by network ray tracing.

Fitting discrete values of interface positions, velocities and density.- prem (data for packages FORMS, MODEL, CRT)
**Preliminary Reference Earth Model (PREM) by Dziewonski and Anderson (1981), specified in geographical spherical coordinates.**

*Examples:*

2-D two-point ray tracing in spherical coordinates.- elf1 (data for packages FORMS, MODEL, CRT)
**Homogeneous layers separated by dipping plane interfaces (model MI).**

*Examples:*

VRML view of complex blocks and interfaces.

3-D two-point ray tracing for moving source and receiver profile.- sd (data for packages FORMS, MODEL)
**Salt dome model and dislocated salt dome model.**

*Examples:*

VRML view of interfaces.- slit (data for packages FORMS, MODEL)
**Slit model.**- wb (data for packages FORMS, MODEL)
**Western Bohemia a priori model.**

*Examples:*

VRML view of velocities and 2-D velocity sections.

Nonlinear location of hypocentre.- l7 (data for packages FORMS, MODEL)
**Model L7.**

*Examples:*

VRML view of interfaces.- mar (data for packages FORMS, MODEL, CRT)
**Gridded 2-D Marmousi model and INRIA bench-mark versions of the 2-D Marmousi model.**

*Examples:*

2-D colour plots of velocities.

Smoothing the Marmousi model for Gaussian-packet migrations.- u2d (data for packages FORMS, MODEL, CRT, FD)
**Unconformity 2-D model by Cormier and Mellen (1984).**

*Examples:*

2-D two-point ray tracing.

Comparison of ray-theory and finite-difference synthetic seismograms.

Example of calculating the derivatives with respect to travel times.- rm (data for packages FORMS, MODEL, CRT, RM, FD)
**Model RM to test ray-matrix synthetic seismograms against 2-D finite differences.**

*Examples:*

Ray-matrix synthetic seismograms.

Finite-difference synthetic seismograms.- qi (data for packages FORMS, MODEL, CRT)
**Anisotropic model QI for comparison of synthetic seismograms with package ANRAY.**

*Examples:*

Coupling ray theory synthetic seismograms in an anisotropic model.- 98 (data for packages FORMS, MODEL, CRT)
**A sample synthetic model created during the technical session of the SW3D consortium meeting in June 1998.**

*Examples:*

VRML view of velocities, interfaces and rays.

3-D two-point ray tracing.

3-D interpolation of travel times within ray cells.

Ray-theory synthetic seismograms.- tc (one-purpose Fortran codes, data for packages FORMS, MODEL, CRT and the one-purpose codes)
**Analytical plane-wave solutions in 1-D anisotropic "twisted crystal" model. Comparison with the results of package CRT and and with the exact solution.**

*Examples:*

Exact analytic solution for a plane wave in a 1-D anisotropic model.

Coupling ray theory synthetic seismograms for a plane wave.- n2 (data for packages MODEL, NET)
**Simple smooth 3-D model to demonstrate network ray tracing in the paper by Klimes and Kvasnicka (1994).**

*Examples:*

Velocity isolines in 2-D sections.

Rays and travel times by network ray tracing.- ran (data for packages FORMS, NET)
**Smooth 2-D random model.**

*Examples:*

Generation of 2-D random model.

First-arrival travel times by 2-D grid travel-time tracing.

2-D colour plots of velocities, travel times and slowness vectors- hess (data for packages FORMS, MODEL)
**2-D model with a salt body by Scott Morton.**

*Examples:*

Smoothing the model for Kirchhoff migrations.- vgr (data for packages FORMS, CRT, NET)
**1-D constant velocity gradient model by Pascal Podvin.**

*Examples:*

Iterative network ray tracing within Fresnel volumes.

Numerical calculation of geometrical spreading from gridded slowness vectors.