Electrical resistivity changes, ground potentials, electromagnetic (EM), and luminous signals preceding or accompanying earthquakes have been reported many times, in addition to ground uplift and tilt and other parameters. ...
A high conductivity zone (HCZ) exists in many places worldwide in the stable mid- to lower continental crust, at the depth of about 20–30 km, but its origin is enigmatic. At this depth range, the temperatures are constrained ...