  Shocks and blastwaves are expected to be driven driven into the intracluster
medium filling galaxy groups and clusters by powerful outbursts of active
galactic nuclei or quasars in the member galaxies; the first footprints of
shock fronts have been tentatively traced out with X-ray imaging. We show how
overpressures in the blasts behind the shock can prove the case and also
provide specific marks of the nuclear activity: its strength, its current
stage, and the nature of its prevailing output. We propose to detect these
marks with the aimed pressure probe constituted by the resolved
Sunyaev-Zel'dovich effect. We compute and discuss the outcomes to be expected
in nearby and distant sources at different stages of their activity.
