  The effect of a "pore-size" length-scale parameter l on compaction of grounds
with fluid inclusions is studied. They are modelled as continua endowed with
micro-structure by means of the macro-modelling procedure proposed in [2]. We
show the dependence of field evolution equations on the micro-structure
parameter l and compare our model with the homogenized asymptotic ones. The
consideration of the pore size 1 allows us to forecast the onset of
micro-displacement waves as a consequence of a ground settling and to suggest a
possible description of the genesis of certain microearthquakes [5] [6].
