GEM is a program to construct physically realistic simulations of earthquake processes.

Simulations are critical to understanding the behavior of fault systems because earthquakes occur at irregular intervals on timescales of hundreds to thousands of years. Simulations generate arbitrarily long seismicity catalogs and provide a numerical laboratory in which the physics of earthquakes can be investigated from a systems viewpoint.

The great wealth of earth science data being collected today provides the means to validate the simulations.

Information technology provides the tools for developing clearly defined accessible data formats and code protocols under a three-tiered user web server program model.