The permanent operation of a 3 axes
SQUID magnetometer in the LSBB below 550 m of calcite rock is a unique system
of magnetic observation: a rejection rate better than 3 fT/$\surd $Hz over
40 Hz. The observation of magneto-ionosphere responses to P wave emissions
both at the epicentre and at their arrival at LSBB for earthquakes of
magnitude larger than 3 is reported. A simple model predicts the starting
time of these events. These results are compared with those provided by
Doppler sounders for ionosphere responses to Rayleigh waves.