The GAM experiment includes four components:

1. solute-, particle and gas tracer tests in the GAM shear zone.
   
   
2. visualisation of the in-situ tracer experiments using high frequency, ground penetrating radar techniques.
   
   
3. laboratory experiments on core samples.
   
   
4. Integrated interpretation of laboratory and field results.

The rationale of using non-sorbing solute tracers (e.g. fluorescent dyes) in combination with particle tracers (microspheres, phages, nanospheres) and gas tracers (He, Xe, SF6, Ar, H2S) is given by their different migration behaviour, allowing for investigation of different domains of the multiple porosity shear zone structure.

• Particle tracers remain within the main flow channels and show no diffusion into the rock matrix or stagnant pores.
  
• Non sorbing solute tracers migrate by advection-diffusion processes and can access entire system of connected porosity.
  
• Gas tracers predominantly migrate along flow channels with large pore radii.

In addition, mass transfer rates of the gas tracer into the liquid phase are characteristic of the specific surface of the gas/water interface along the gas flowpaths.