avvisatore of seismic event is imminent based on detection of local variations of the direction of the geomagnetic field.

摘要

The high state of stress of rock masses from 1 to 10 days before the moment of fracture causing an earthquake produces in the focal zone an alteration in the electromagnetic conditions of the affected rocks with a resultant variation of terrestrial magnetic field (tmf) detectable on the surface. The invention described here, already implemented and tested in a prototype is capable of: 1) continuously detecting local variations of the direction of the tmf by means of two detectors consisting respectively of a declination compass and an inclination compass; 2) representing them with electrical signals through optoelectronic pickups that detect movements of the magnetic needles; 3) communicating an alarm when the variations exceed a specified threshold detectable with a discriminator with a window. The invention has the purpose of furnishing useful prediction of earthquakes with the possibility of functioning in a domestic setting, offering for the first time an opportunity for individual citizens to find out in time the probable occurrence of an earthquake. Thus far no detectors of variations of direction (much more significant for prediction than intensity) have offered the possibility of continuous monitoring and no variometer or magnetometer has ever been used with an apparatus having the specific purpose of giving a seismic alarm.