Understanding how Earth’s moving tectonic plates can dive or subduct beneath another to create earthquake-generating faults is critical for risk assessment in subduction zones. Fluids released by devolatilization reactions (e.g. H2O, CO2) are generally invoked to explain a wide range of petrological and mechanical processes documented by both experimental and geophysical observations such as arc magmatism, mantle wedge serpentinization and metasomatic reactions or seismic activity and episodic transient slip events. In the 30-60 km depth region in the Blueschist facies, seismological evidence point to high pore fluid pressures (as shown by high Vp/Vs or Poisson’s ratios) and low stresses on the interface that are spatially associated with the breakdown of water-bearing minerals. In detail, relationships between fluid extraction, channelization processes and stress distribution are the main scope of this thesis and discussions with possible relations with the earthquake cycle will likely improve our knowledge of such phenomena.