The application discloses a process and apparatus for characterising the evolution of a reservoir by co-analyzing the changes in the propagation times and seismic amplitudes of seismic reflections. The melt supplied enters the permanent mold at a speed whose relationship with respect to the strand withdrawal speed is:. , from an atmosphere having a temperature that is at least equal to 0\xb0 C. The method enables the speech server to conduct the call and transfer information therefrom to at least one other server.