From a physical and mechanical point of view, it is not plausible to
explain these fast changes with mechanical transport of large masses
or strong variations of the temperature in the crust. We propose that
the observed changes of seismic parameters are related to variations
of the stress and deformation fields and fast fluid transport through
the rocks of the crust. To explain the features recovered in the 4D
seismic model, we propose the qualitative scenario illustrated in Fig. 8.