Underground monitoring system of electromagnetic emissions

In the last few years systematic investigations concerning electromagnetic precursors of earthquakes have been carried out by many authors. The studies regarding the electric component of electromagnetic emissions are made with surface or underground equipments. An electromagnetic-emission monitoring system suitable for underground deployment has been made at the Physic Departement of the ''La Sapienza'' University of Rome. The system is able to detect electric signals with an amplitude up to about 100 mV and a frequency band that lies between 0.3 and 300 Hz