The GEM collaboration is aimed at developing the computational capability(knowhow, software and access to hardware) to carry out large scale numerical simulations of the physics of  earthquakes in Southern California and elsewhere. These simulations would produce detailed temporal and spatial patterns of earthquakes, surface deformation and gravity change, seismicity, stress, as well as, in principle, other variables, including pore fluid and thermal ch anges, for comparison to

field and laboratory data. The recent advances in geophysical data gathering and the continued increase in high performance computing, are key enabling developments for GEM.

To aid construction of the simulations, a state-of-the-art problem solving environment must be developed that will facilitate:

• Construction of numerical and computational algorithms and specific environment(s) needed to carry out large scale simulations of these nonlinear physical processes over a  geographically distributed, heterogeneous computing network; and
• Development of a testbed for earthquake "forecasting" and "prediction" methodologies which uses modern Object Oriented techniques and scalable systems, so ftware and algorithms which are efficient for both people and computational execution time.