Analysis on electromagnetic field of coal or rock body fracture with taking a vertical electrical dipole as the emitter by the Counter-Propagation Deduction (CPD) method

A three-layer medium model set up according to the theory of electromagnetic emission of coal or rock body fracture with taking a vertical electrical dipole in the middle layer as the emitter is analyzed by the Counter-Propagation Deduction (CPD) method. The analytical expressions of Hertz vector and the magnetic field strength in the middle layer are obtained. The results may help to locate the area where coal or rock body fracture occurs.