Geotools Corporation
Geophysical Software for Magnetotellurics (MT) and Gravity.

ORFEUS Seismological Software
Maintains a Seismological Software Library (SSL) with web- and ftp-site links..

GeoTrace
Provides high technology seismic data processing services and software to the oil and gas industry worldwide.

Rayfract
Geophysical data interpretation software provides subsurface seismic velocity models.

EiKon Technologies/Petros EiKon
Offers electromagnetic and magnetic 3D modelling and inversion software (EMIGMA) for sale and lease.

Sandmeier Scientific Software
Ground-Penetrating-Radar ( GPR ) and reflection/refraction-seismic data processing software as well as solutions for various other near-surface geophysical applications like ultrasound and geoelectric.

SeisScape
Seismic visualization software Birch Tree Software.

GX Technology
Seismic exploration software tools available (seismic modeling and imaging). Also papers on their application.

Reflection Exploration
Windows-based software for seismic processing and velocity analysis.

Green Mountain Geophysics
Geophysical software for use in the petroleum industry.

GprMax - Numerical Simulator for GPR
GprMax 2D and 3D numerical simulator for Ground Penetrating Radar. Free to use for research and teaching purposes and can be used to create synthetic GPR responses from complex targets.